Release v1.7.3

Since those values are not stored on Hex, we should not
expect them to be available on Mix.Dep.cached. Instead
we traverse the deps in `mix.exs` to lift this information.

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

.appveyor.yml

@@ -0,0 +1,18 @@
+version: 1-{branch}+{build}
+
+build_script:
+  - cmd: C:\MinGW\msys\1.0\bin\make
+  - cmd: rmdir /s /q .git
+before_test:
+  - cmd: set PATH=%PATH%;C:\Program Files\erl8.3\erts-8.3\bin
+test_script:
+  - cmd: C:\MinGW\msys\1.0\bin\make --keep-going test_windows
+
+environment:
+  ELIXIR_ASSERT_TIMEOUT: 2000
+
+matrix:
+  allow_failures:
+    - platform: x86
+    - platform: x64
+    - platform: Any CPU

.cirrus.yml

@@ -1,50 +0,0 @@
-env:
-  CIRRUS_CLONE_DEPTH: 50
-  ELIXIR_ASSERT_TIMEOUT: 2000
-  ELIXIRC_OPTS: "--warnings-as-errors"
-  ERLC_OPTS: "warnings_as_errors"
-  LANG: C.UTF-8
-
-test_template: &DEFAULT_TEST_SETTINGS
-  # don't cancel the task execution if it's master or a release branch
-  auto_cancellation: $CIRRUS_BRANCH != 'master' && $CIRRUS_BRANCH !=~ 'v\d+\.\d+.*'
-
-test_freebsd_task:
-  <<: *DEFAULT_TEST_SETTINGS
-
-  name: FreeBSD 13.0
-  alias: FreeBSD Stable
-
-  freebsd_instance:
-    image_family: freebsd-13-0
-    cpu: 8
-    memory: 7424Mi
-
-  env:
-    CHECK_REPRODUCIBLE: true
-    LC_ALL: en_US.UTF-8
-    PATH: $PATH:/usr/local/lib/erlang24/bin
-
-  install_script:
-    - pkg install -y erlang-runtime24 git gmake
-    - rm -rf .git
-    - gmake compile
-
-  build_info_script: bin/elixir --version
-
-  test_formatted_script:
-    - gmake test_formatted &&
-      echo "All Elixir source code files are properly formatted."
-
-  dialyzer_script: dialyzer -pa lib/elixir/ebin --build_plt --output_plt elixir.plt --apps lib/elixir/ebin/elixir.beam lib/elixir/ebin/Elixir.Kernel.beam
-
-  test_erlang_script: gmake test_erlang
-
-  test_elixir_script: gmake test_elixir
-
-  check_reproducible_script: |
-    if [ -n "$CHECK_REPRODUCIBLE" ]; then
-      gmake check_reproducible
-    else
-      echo "The reproducibility of the build is only checked in the last stable Erlang/OTP version."
-    fi

.formatter.exs

@@ -1,10 +1,9 @@
 [
   inputs: [
     "lib/*/{lib,unicode,test}/**/*.{ex,exs}",
-    "lib/*/*.exs",
-    "lib/ex_unit/examples/*.exs",
-    ".formatter.exs"
+    "lib/*/mix.exs"
   ],
+
   locals_without_parens: [
     # Formatter tests
     assert_format: 2,
@@ -14,6 +13,5 @@
 
     # Errors tests
     assert_eval_raise: 3
-  ],
-  normalize_bitstring_modifiers: false
+  ]
 ]

.gitattributes

@@ -1,3 +1 @@
 lib/elixir/test/elixir/fixtures/*.txt text eol=lf
-*.ex diff=elixir
-*.exs diff=elixir

.github/ISSUE_TEMPLATE/config.yml

@@ -1,11 +0,0 @@
----
-blank_issues_enabled: true
-
-contact_links:
-  - name: Discuss proposals
-    url: https://groups.google.com/g/elixir-lang-core
-    about: Send proposals for new ideas to our mailing list
-
-  - name: Ask questions and support
-    url: https://elixirforum.com/
-    about: Ask questions, provide support and more on Elixir Forum

.github/ISSUE_TEMPLATE/issue.yml

@@ -1,53 +0,0 @@
----
-name: Report an issue
-description:
-  Tell us about something that is not working the way we (probably) intend
-body:
-  - type: markdown
-    attributes:
-      value: >
-        Thank you for contributing to Elixir! :heart:
-
-
-        Please, do not use this form for guidance, questions or support.
-        Try instead in [Elixir Forum](https://elixirforum.com),
-        the [IRC Chat](https://web.libera.chat/#elixir),
-        [Stack Overflow](https://stackoverflow.com/questions/tagged/elixir),
-        [Slack](https://elixir-slackin.herokuapp.com),
-        [Discord](https://discord.gg/elixir) or in other online communities.
-
-  - type: textarea
-    id: elixir-and-otp-version
-    attributes:
-      label: Elixir and Erlang/OTP versions
-      description: Paste the output of `elixir --version` here.
-    validations:
-      required: true
-
-  - type: input
-    id: os
-    attributes:
-      label: Operating system
-      description: The operating system that this issue is happening on.
-    validations:
-      required: true
-
-  - type: textarea
-    id: current-behavior
-    attributes:
-      label: Current behavior
-      description: >
-        Include code samples, errors, and stacktraces if appropriate.
-
-
-        If reporting a bug, please include the reproducing steps.
-    validations:
-      required: true
-
-  - type: textarea
-    id: expected-behavior
-    attributes:
-      label: Expected behavior
-      description: A short description on how you expect the code to behave.
-    validations:
-      required: true

.github/dependabot.yml

@@ -1,6 +0,0 @@
-version: 2
-updates:
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "weekly"

.github/workflows/ci.yml

@@ -1,129 +0,0 @@
-name: CI
-
-on: [pull_request, push]
-
-env:
-  ELIXIR_ASSERT_TIMEOUT: 2000
-  ELIXIRC_OPTS: "--warnings-as-errors"
-  ERLC_OPTS: "warnings_as_errors"
-  LANG: C.UTF-8
-
-permissions:
-  contents: read
-
-jobs:
-  test_linux:
-    name: Linux, ${{ matrix.otp_release }}, Ubuntu 18.04
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - otp_release: OTP-25.0
-            otp_latest: true
-          - otp_release: OTP-24.3
-          - otp_release: OTP-24.0
-          - otp_release: OTP-23.3
-          - otp_release: OTP-23.0
-          - otp_release: master
-            development: true
-          - otp_release: maint
-            development: true
-    runs-on: ubuntu-18.04
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 50
-      - name: Install Erlang/OTP
-        run: |
-          cd $RUNNER_TEMP
-          wget -O otp.tar.gz https://repo.hex.pm/builds/otp/ubuntu-18.04/${{ matrix.otp_release }}.tar.gz
-          mkdir -p otp
-          tar zxf otp.tar.gz -C otp --strip-components=1
-          otp/Install -minimal $(pwd)/otp
-          echo "$(pwd)/otp/bin" >> $GITHUB_PATH
-      - name: Compile Elixir
-        run: |
-          rm -rf .git
-          make compile
-          echo "$PWD/bin" >> $GITHUB_PATH
-      - name: Build info
-        run: bin/elixir --version
-      - name: Check format
-        run: make test_formatted && echo "All Elixir source code files are properly formatted."
-      - name: Run Dialyzer
-        run: dialyzer -pa lib/elixir/ebin --build_plt --output_plt elixir.plt --apps lib/elixir/ebin/elixir.beam lib/elixir/ebin/Elixir.Kernel.beam
-      - name: Erlang test suite
-        run: make test_erlang
-        continue-on-error: ${{ matrix.development }}
-      - name: Elixir test suite
-        run: make test_elixir
-        continue-on-error: ${{ matrix.development }}
-      - name: Check reproducible builds
-        run: taskset 1 make check_reproducible
-        if: ${{ matrix.otp_latest }}
-      - name: Build docs
-        if: ${{ matrix.otp_latest }}
-        run: |
-          git config --global advice.detachedHead false
-          EX_DOC_LATEST_STABLE_VERSION=$(curl -s https://hex.pm/api/packages/ex_doc | jq --raw-output '.latest_stable_version')
-          for branch in main v${EX_DOC_LATEST_STABLE_VERSION}; do
-            echo "Building docs with ExDoc ${branch}"
-            cd ..
-            git clone https://github.com/elixir-lang/ex_doc.git --branch ${branch} --depth 1
-            cd ex_doc
-            ../elixir/bin/mix do local.rebar --force + local.hex --force + deps.get + compile
-            cd ../elixir/
-            make docs
-            rm -rf ../ex_doc/
-          done
-
-  test_windows:
-    name: Windows, OTP-${{ matrix.otp_release }}, Windows Server 2019
-    strategy:
-      matrix:
-        otp_release: ['23.3']
-    runs-on: windows-2019
-    steps:
-      - name: Configure Git
-        run: git config --global core.autocrlf input
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 50
-      - name: Cache Erlang/OTP package
-        uses: actions/cache@v3
-        with:
-          path: C:\Users\runneradmin\AppData\Local\Temp\chocolatey\erlang
-          key: OTP-${{ matrix.otp_release }}-windows-2019
-      - name: Install Erlang/OTP
-        run: choco install -y erlang --version ${{ matrix.otp_release }}
-      - name: Compile Elixir
-        run: |
-          remove-item '.git' -recurse -force
-          make compile
-      - name: Build info
-        run: bin/elixir --version
-      - name: Check format
-        run: make test_formatted && echo "All Elixir source code files are properly formatted."
-      - name: Erlang test suite
-        run: make --keep-going test_erlang
-      - name: Elixir test suite
-        run: |
-          del c:/Windows/System32/drivers/etc/hosts
-          make --keep-going test_elixir
-
-  check_posix_compliant:
-    name: Check POSIX-compliant
-    runs-on: ubuntu-18.04
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 50
-      - name: Install Shellcheck
-        run: |
-          sudo apt update
-          sudo apt install -y shellcheck
-      - name: Check POSIX-compliant
-        run: |
-          shellcheck -e SC2039,2086 bin/elixir && echo "bin/elixir is POSIX compliant"
-          shellcheck bin/elixirc && echo "bin/elixirc is POSIX compliant"
-          shellcheck bin/iex && echo "bin/iex is POSIX compliant"

.github/workflows/notify.exs

@@ -1,72 +0,0 @@
-# #!/usr/bin/env elixir
-[tag] = System.argv()
-
-Mix.install([
-  {:req, "~> 0.2.1"},
-  {:jason, "~> 1.0"}
-])
-
-%{status: 200, body: release} =
-  Req.get!("https://api.github.com/repos/elixir-lang/elixir/releases/tags/#{tag}")
-
-if release["draft"] do
-  raise "cannot notify a draft release"
-end
-
-## Notify on elixir-lang-ann
-
-names_and_checksums =
-  for asset <- release["assets"],
-      name = asset["name"],
-      name =~ ~r/.sha\d+sum$/,
-      do: {name, Req.get!(asset["browser_download_url"]).body}
-
-line_items =
-  for {name, checksum_and_name} <- Enum.sort(names_and_checksums) do
-    [checksum | _] = String.split(checksum_and_name, " ")
-    root = Path.rootname(name)
-    "." <> type = Path.extname(name)
-    "  * #{root} - #{type} - #{checksum}\n"
-  end
-
-mail = %{
-  "From" => "jose.valim@dashbit.co",
-  "To" => "elixir-lang-ann@googlegroups.com",
-  "Subject" => "Elixir #{tag} released",
-  "HtmlBody" => "https://github.com/elixir-lang/elixir/releases/tag/#{tag}\n\n#{line_items}",
-  "MessageStream" => "outbound"
-}
-
-if System.get_env("DRYRUN") do
-  IO.puts("MAIL")
-  IO.inspect(mail)
-else
-  headers = %{
-    "X-Postmark-Server-Token" => System.fetch_env!("ELIXIR_LANG_ANN_TOKEN")
-  }
-
-  resp = Req.post!("https://api.postmarkapp.com/email", {:json, mail}, headers: headers)
-  IO.puts("#{resp.status} elixir-lang-ann\n#{inspect(resp.body)}")
-end
-
-## Notify on Elixir Forum
-
-post = %{
-  "title" => "Elixir #{tag} released",
-  "raw" => "https://github.com/elixir-lang/elixir/releases/tag/#{tag}\n\n#{release["body"]}",
-  # Elixir News
-  "category" => 28
-}
-
-if System.get_env("DRYRUN") do
-  IO.puts("POST")
-  IO.inspect(post)
-else
-  headers = %{
-    "api-key" => System.fetch_env!("ELIXIR_FORUM_TOKEN"),
-    "api-username" => "Elixir"
-  }
-
-  resp = Req.post!("https://elixirforum.com/posts.json", {:json, post}, headers: headers)
-  IO.puts("#{resp.status} Elixir Forum\n#{inspect(resp.body)}")
-end

.github/workflows/notify.yml

@@ -1,28 +0,0 @@
-name: Notify
-
-on:
-  release:
-    types:
-      - published
-
-permissions:
-  contents: read
-
-jobs:
-  notify:
-    runs-on: ubuntu-18.04
-    name: Notify
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 50
-      - uses: erlef/setup-beam@v1
-        with:
-          otp-version: 24.3
-          elixir-version: 1.13.4
-      - name: Run Elixir script
-        env:
-          ELIXIR_FORUM_TOKEN: ${{ secrets.ELIXIR_FORUM_TOKEN }}
-          ELIXIR_LANG_ANN_TOKEN: ${{ secrets.ELIXIR_LANG_ANN_TOKEN }}
-        run: |
-          elixir .github/workflows/notify.exs ${{ github.ref_name }}

.github/workflows/release.yml

@@ -1,96 +0,0 @@
-name: Release
-
-on:
-  push:
-    tags:
-      - v*
-
-env:
-  ELIXIR_OPTS: "--warnings-as-errors"
-  ERLC_OPTS: "warnings_as_errors"
-  LANG: C.UTF-8
-
-jobs:
-  create_draft_release:
-    permissions:
-      contents: write
-    runs-on: ubuntu-18.04
-    env:
-      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    steps:
-      - name: Create draft release
-        run: |
-          gh release create \
-            --repo ${{ github.repository }} \
-            --title ${{ github.ref_name }} \
-            --notes '' \
-            --draft \
-            ${{ github.ref_name }}
-  release_pre_built:
-    needs: create_draft_release
-    strategy:
-      fail-fast: true
-      matrix:
-        include:
-          - otp: 23
-            otp_version: 23.3
-          - otp: 24
-            otp_version: 24.3
-          - otp: 25
-            otp_version: 25.0
-            build_docs: build_docs
-    runs-on: ubuntu-18.04
-    steps:
-      - uses: actions/checkout@v3
-        with:
-          fetch-depth: 50
-      - uses: erlef/setup-beam@v1
-        with:
-          otp-version: ${{ matrix.otp_version }}
-          version-type: strict
-      - name: Build Elixir Release
-        run: |
-          make Precompiled.zip
-          mv Precompiled.zip elixir-otp-${{ matrix.otp }}.zip
-          shasum -a 1 elixir-otp-${{ matrix.otp }}.zip > elixir-otp-${{ matrix.otp }}.zip.sha1sum
-          shasum -a 256 elixir-otp-${{ matrix.otp }}.zip > elixir-otp-${{ matrix.otp }}.zip.sha256sum
-          echo "$PWD/bin" >> $GITHUB_PATH
-      - name: Upload Pre-built
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: |
-          gh release upload --clobber "${{ github.ref_name }}" \
-            elixir-otp-${{ matrix.otp }}.zip \
-            elixir-otp-${{ matrix.otp }}.zip.sha{1,256}sum
-      - name: Get latest stable ExDoc version
-        if: ${{ matrix.build_docs }}
-        run: |
-          EX_DOC_LATEST_STABLE_VERSION=$(curl -s https://hex.pm/api/packages/ex_doc | jq --raw-output '.latest_stable_version')
-          echo "EX_DOC_LATEST_STABLE_VERSION=${EX_DOC_LATEST_STABLE_VERSION}" >> $GITHUB_ENV
-      - uses: actions/checkout@v3
-        if: ${{ matrix.build_docs }}
-        with:
-          repository: elixir-lang/ex_doc
-          ref: v${{ env.EX_DOC_LATEST_STABLE_VERSION }}
-          path: ex_doc
-      - name: Build ex_doc
-        if: ${{ matrix.build_docs }}
-        run: |
-          mv ex_doc ../ex_doc
-          cd ../ex_doc
-          ../elixir/bin/mix do local.rebar --force + local.hex --force + deps.get + compile
-          cd ../elixir
-      - name: Build Docs
-        if: ${{ matrix.build_docs }}
-        run: |
-          make Docs.zip
-          shasum -a 1 Docs.zip > Docs.zip.sha1sum
-          shasum -a 256 Docs.zip > Docs.zip.sha256sum
-      - name: Upload Docs
-        if: ${{ matrix.build_docs }}
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: |
-          gh release upload --clobber "${{ github.ref_name }}" \
-            Docs.zip \
-            Docs.zip.sha{1,256}sum

.travis.yml

@@ -0,0 +1,44 @@
+language: bash
+sudo: false
+
+env:
+  global:
+    - ELIXIR_ASSERT_TIMEOUT=2000
+  matrix:
+    - OTP_RELEASE=OTP-19.0
+    - OTP_RELEASE=OTP-19.1
+    - OTP_RELEASE=OTP-19.2
+    - OTP_RELEASE=OTP-19.3
+    - OTP_RELEASE=OTP-20.0
+    - OTP_RELEASE=OTP-20.1
+    - OTP_RELEASE=OTP-20.2
+    - OTP_RELEASE=OTP-20.3
+    - OTP_RELEASE=OTP-21.0
+    - OTP_RELEASE=maint
+    - OTP_RELEASE=master
+
+matrix:
+  fast_finish: true
+  allow_failures:
+    - env: OTP_RELEASE=maint
+    - env: OTP_RELEASE=master
+
+install:
+  - wget -O otp.tar.gz https://repo.hex.pm/builds/otp/ubuntu-14.04/${OTP_RELEASE}.tar.gz
+  - mkdir -p otp
+  - tar zxf otp.tar.gz -C otp --strip-components=1
+  - otp/Install -minimal $(pwd)/otp
+  - PATH=$(pwd)/otp/bin:$PATH
+
+script:
+  - make compile
+  - rm -rf .git
+  - make test
+  - dialyzer -pa lib/elixir/ebin --build_plt --output_plt elixir.plt --apps lib/elixir/ebin/elixir.beam lib/elixir/ebin/Elixir.Kernel.beam
+
+notifications:
+  recipients:
+    - jose.valim@gmail.com
+    - eric.meadows.jonsson@gmail.com
+    - lexmag@me.com
+    - an.leopardi@gmail.com

CHANGELOG.md

@@ -1,479 +1,284 @@
-# Changelog for Elixir v1.14
+# Changelog for Elixir v1.7
 
-Elixir v1.14 brings many improvements to the debugging experience in Elixir
-and data-type inspection. It also includes a new abstraction for easy
-partitioning of processes called `PartitionSupervisor`, as well as improved
-compilation times and error messages.
+Elixir v1.7 is the last release to support Erlang/OTP 19. We recommend everyone to migrate to Erlang/OTP 20+.
 
-Elixir v1.14 is the last version to support Erlang/OTP 23. Consider updating
-to Erlang/OTP 24 or Erlang/OTP 25.
+## Documentation metadata
 
-## `dbg`
-
-`Kernel.dbg/2` is a new macro that's somewhat similar to `IO.inspect/2`, but
-specifically tailored for **debugging**.
-
-When called, it prints the value of whatever you pass to it, plus the debugged
-code itself as well as its location. This code:
+Elixir v1.7 implements [EEP 48](http://erlang.org/eep/eeps/eep-0048.html). EEP 48 aims to bring documentation interoperability across all languages running on the Erlang VM. The documentation format proposed by EEP 48 also supports metadata, which is now fully exposed to Elixir developers:
 
 ```elixir
-# In my_file.exs
-feature = %{name: :dbg, inspiration: "Rust"}
-dbg(feature)
-dbg(Map.put(feature, :in_version, "1.14.0"))
+@moduledoc "A brand new module"
+@moduledoc authors: ["Jane", "Mary"], since: "1.4.0"
 ```
 
-Prints this:
+Passing metadata is supported on `@doc`, `@moduledoc` and `@typedoc`.
 
-```shell
-$ elixir my_file.exs
-[my_file.exs:2: (file)]
-feature #=> %{inspiration: "Rust", name: :dbg}
+To access the new documentation format, developers should use `Code.fetch_docs/1`. The old documentation format is no longer available and the old `Code.get_docs/2` function will return `nil` accordingly.
 
-[my_file.exs:3: (file)]
-Map.put(feature, :in_version, "1.14.0") #=> %{in_version: "1.14.0", inspiration: "Rust", name: :dbg}
-```
+Tools like IEx and ExDoc have been updated to leverage the new format and show relevant metadata to users. While Elixir allows any metadata to be given, those tools currently exhibit only `:deprecated` and `:since`. Other keys may be shown in the future.
 
-`dbg/2` can do more. It's a macro, so it *understands Elixir code*. You can see
-that when you pass a series of `|>` pipes to it. `dbg/2` will print the value
-for every step of the pipeline. This code:
+## The `__STACKTRACE__` construct
+
+Erlang/OTP 21.0 introduces a new way to retrieve the stacktrace that is lexically scoped and no longer relies on side-effects like `System.stacktrace/0` does. Before one would write:
 
 ```elixir
-# In dbg_pipes.exs
-__ENV__.file
-|> String.split("/", trim: true)
-|> List.last()
-|> File.exists?()
-|> dbg()
+try do
+  ... something that may fail ...
+rescue
+  e ->
+    log(e, System.stacktrace())
+    reraise(e, System.stacktrace())
+end
 ```
 
-Prints this:
-
-```shell
-$ elixir dbg_pipes.exs
-[dbg_pipes.exs:5: (file)]
-__ENV__.file #=> "/home/myuser/dbg_pipes.exs"
-|> String.split("/", trim: true) #=> ["home", "myuser", "dbg_pipes.exs"]
-|> List.last() #=> "dbg_pipes.exs"
-|> File.exists?() #=> true
-```
-
-### IEx and Prying
-
-`dbg/2` supports configurable backends. IEx automatically replaces the default
-backend by one that halts the code execution with `IEx.Pry`, giving developers
-the option to access local variables, imports, and more. This also works with
-pipelines: if you pass a series of `|>` pipe calls to `dbg` (or pipe into it at the
-end, like `|> dbg()`), you'll be able to step through every line in the pipeline.
-
-You can keep the default behaviour by passing the `--no-pry` option to IEx.
-
-## PartitionSupervisor
-
-`PartitionSupervisor` is a new module that implements a new supervisor type. The
-partition supervisor is designed to help with situations where you have a single
-supervised process that becomes a bottleneck. If that process's state can be
-easily partitioned, then you can use `PartitionSupervisor` to supervise multiple
-isolated copies of that process running concurrently, each assigned its own
-partition.
-
-For example, imagine you have an `ErrorReporter` process that you use to report
-errors to a monitoring service.
+In Elixir v1.7, this can be written as:
 
 ```elixir
-# Application supervisor:
-children = [
-  # ...,
-  ErrorReporter
-]
-
-Supervisor.start_link(children, strategy: :one_for_one)
+try do
+  ... something that may fail ...
+rescue
+  e ->
+    log(e, __STACKTRACE__)
+    reraise(e, __STACKTRACE__)
+end
 ```
 
-As the concurrency of your application goes up, the `ErrorReporter` process
-might receive requests from many other processes and eventually become a
-bottleneck. In a case like this, it could help to spin up multiple copies of the
-`ErrorReporter` process under a `PartitionSupervisor`.
+This change may also yield performance improvements in the future, since the lexical scope allows us to track precisely when a stacktrace is used and we no longer need to keep references to stacktrace entries after the `try` construct finishes.
+
+Other parts of the exception system have been improved. For example, more information is provided in certain occurrences of `ArgumentError`, `ArithmeticError` and `KeyError` messages.
+
+## Erlang/OTP logger integration
+
+Erlang/OTP 21 includes a new `:logger` module. Elixir v1.7 fully integrates with the new `:logger` and leverages its metadata system. The `Logger.Translator` mechanism has also been improved to export metadata, allowing custom Logger backends to leverage information such as:
+
+  * `:crash_reason` - a two-element tuple with the throw/error/exit reason as first argument and the stacktrace as second
+
+  * `:initial_call` - the initial call that started the process
+
+  * `:registered_name` - the process registered name as an atom
+
+We recommend Elixir libraries that previously hooked into Erlang's `:error_logger` to hook into `Logger` instead, in order to support all current and future Erlang/OTP versions.
+
+## Other Logger improvements
+
+Previously, Logger macros such as `debug`, `info`, and so on would always evaluate their arguments, even when nothing would be logged. From Elixir v1.7, the arguments are only evaluated when the message is logged.
+
+The Logger configuration system also accepts a new option called `:compile_time_purge_matching` that allows you to remove log calls with specific compile-time metadata. For example, to remove all logger calls from application `:foo` with level lower than `:info`, as well as remove all logger calls from `Bar.foo/3`, you can use the following configuration:
 
 ```elixir
-# Application supervisor
-children = [
-  {PartitionSupervisor, child_spec: ErrorReporter, name: Reporters}
-]
+config :logger,
+  compile_time_purge_matching: [
+    [application: :foo, level_lower_than: :info],
+    [module: Bar, function: "foo/3"]
+  ]
 ```
 
-The `PartitionSupervisor` will spin up a number of processes equal to
-`System.schedulers_online()` by default (most often one per core). Now, when
-routing requests to `ErrorReporter` processes we can use a `:via` tuple and
-route the requests through the partition supervisor.
+## ExUnit improvements
 
-```elixir
-partitioning_key = self()
-ErrorReporter.report({:via, PartitionSupervisor, {Reporters, partitioning_key}}, error)
+ExUnit has also seen its own share of improvements. Assertions such as `assert some_fun(arg1, arg2, arg3)` will now include the value of each argument in the failure report:
+
+```
+  1) test function call arguments (TestOneOfEach)
+     lib/ex_unit/examples/one_of_each.exs:157
+     Expected truthy, got false
+     code: assert some_vars(1 + 2, 3 + 4)
+     arguments:
+
+         # 1
+         3
+
+         # 2
+         7
+
+     stacktrace:
+       lib/ex_unit/examples/one_of_each.exs:158: (test)
 ```
 
-Using `self()` as the partitioning key here means that the same process will
-always report errors to the same `ErrorReporter` process, ensuring a form of
-back-pressure. You can use any term as the partitioning key.
+Furthermore, failures in doctests are now colored and diffed.
 
-### A Common Example
+On the `mix test` side of things, there is a new `--failed` flag that runs all tests that failed the last time they ran. Finally, coverage reports generated with `mix test --cover` include a summary out of the box:
 
-A common and practical example of a good use case for `PartitionSupervisor` is
-partitioning something like a `DynamicSupervisor`. When starting many processes
-under it, a dynamic supervisor can be a bottleneck, especially if said processes
-take a long time to initialize. Instead of starting a single `DynamicSupervisor`,
-you can start multiple:
+```
+Generating cover results ...
 
-```elixir
-children = [
-  {PartitionSupervisor, child_spec: DynamicSupervisor, name: MyApp.DynamicSupervisors}
-]
-
-Supervisor.start_link(children, strategy: :one_for_one)
+Percentage | Module
+-----------|--------------------------
+   100.00% | Plug.Exception.Any
+   100.00% | Plug.Adapters.Cowboy2.Stream
+   100.00% | Collectable.Plug.Conn
+   100.00% | Plug.Crypto.KeyGenerator
+   100.00% | Plug.Parsers
+   100.00% | Plug.Head
+   100.00% | Plug.Router.Utils
+   100.00% | Plug.RequestId
+       ... | ...
+-----------|--------------------------
+    77.19% | Total
 ```
 
-Now you start processes on the dynamic supervisor for the right partition.
-For instance, you can partition by PID, like in the previous example:
+## v1.7.3 (2018-08-24)
 
-```elixir
-DynamicSupervisor.start_child(
-  {:via, PartitionSupervisor, {MyApp.DynamicSupervisors, self()}},
-  my_child_specification
-)
-```
+### 1. Bug fixes
 
-## Improved errors on binaries and evaluation
+#### ExUnit
 
-Erlang/OTP 25 improved errors on binary construction and evaluation. These improvements
-apply to Elixir as well. Before v1.14, errors when constructing binaries would
-often be hard-to-debug generic "argument errors". With Erlang/OTP 25 and Elixir v1.14,
-more detail is provided for easier debugging. This work is part of [EEP
-54](https://www.erlang.org/eeps/eep-0054).
+  * [ExUnit.Assertions] Do not attempt to expand `try/1` as it is a special form
 
-Before:
+#### Mix
 
-```elixir
-int = 1
-bin = "foo"
-int <> bin
-#=> ** (ArgumentError) argument error
-```
+  * [mix compile.app] Do not include applications with `runtime: false` as a runtime dependency for applications coming from Hex
 
-Now:
+## v1.7.2 (2018-08-05)
 
-```elixir
-int = 1
-bin = "foo"
-int <> bin
-#=> ** (ArgumentError) construction of binary failed:
-#=>    segment 1 of type 'binary':
-#=>    expected a binary but got: 1
-```
+### 1. Bug fixes
 
-## Slicing with steps
+#### Elixir
 
-Elixir v1.12 introduced **stepped ranges**, which are ranges where you can
-specify the "step":
+  * [DateTime] Take negative years into account in `DateTime.from_iso8601/1`
+  * [Kernel] Do not emit warnings for repeated docs over different clauses due to false positives
 
-```elixir
-Enum.to_list(1..10//3)
-#=> [1, 4, 7, 10]
-```
+#### Mix
 
-Stepped ranges are particularly useful for numerical operations involving
-vectors and matrices (see [Nx](https://github.com/elixir-nx/nx), for example).
-However, the Elixir standard library was not making use of stepped ranges in its
-APIs. Elixir v1.14 starts to take advantage of steps with support for stepped
-ranges in a couple of functions. One of them is `Enum.slice/2`:
+  * [mix compile] Properly mark top-level dependencies as optional and as runtime. This fixes a bug where Mix attempted to start optional dependencies of a package when those optional dependencies were not available
+  * [mix compile] Avoid deadlock when a config has a timestamp later than current time
+  * [mix help] Show task and alias help when both are available
+  * [mix test] Do not fail suite if there are no test files
 
-```elixir
-letters = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j"]
-Enum.slice(letters, 0..5//2)
-#=> ["a", "c", "e"]
-```
+## v1.7.1 (2018-07-26)
 
-`binary_slice/2` (and `binary_slice/3` for completeness) has been added to the
-`Kernel` module, that works with bytes and also support stepped ranges:
+### 1. Bug fixes
 
-```elixir
-binary_slice("Elixir", 1..5//2)
-#=> "lxr"
-```
+#### Elixir
 
-## Expression-based inspection and `Inspect` improvements
+  * [Calendar] Work-around a Dialyzer bug that causes it to loop for a long time, potentially indefinitely
 
-In Elixir, it's conventional to implement the `Inspect` protocol for opaque
-structs so that they're inspected with a special notation, resembling this:
-
-```elixir
-MapSet.new([:apple, :banana])
-#MapSet<[:apple, :banana]>
-```
-
-This is generally done when the struct content or part of it is private and the
-`%name{...}` representation would reveal fields that are not part of the public
-API.
-
-The downside of the `#name<...>` convention is that *the inspected output is not
-valid Elixir code*. For example, you cannot copy the inspected output and paste
-it into an IEx session.
-
-Elixir v1.14 changes the convention for some of the standard-library structs.
-The `Inspect` implementation for those structs now returns a string with a valid
-Elixir expression that recreates the struct when evaluated. In the `MapSet`
-example above, this is what we have now:
-
-```elixir
-fruits = MapSet.new([:apple, :banana])
-MapSet.put(fruits, :pear)
-#=> MapSet.new([:apple, :banana, :pear])
-```
-
-The `MapSet.new/1` expression evaluates to exactly the struct that we're
-inspecting. This allows us to hide the internals of `MapSet`, while keeping
-it as valid Elixir code. This expression-based inspection has been
-implemented for `Version.Requirement`, `MapSet`, and `Date.Range`.
-
-Finally, we have improved the `Inspect` protocol for structs so that
-fields are inspected in the order they are declared in `defstruct`.
-The option `:optional` has also been added when deriving the `Inspect`
-protocol, giving developers more control over the struct representation.
-See the updated documentation for `Inspect` for a general rundown on
-the approaches and options available.
-
-## v1.14.1 (2022-10-10)
+## v1.7.0 (2018-07-25)
 
 ### 1. Enhancements
 
 #### Elixir
 
-  * [Kernel] Perform partial expansion of literals in module attributes
-  * [Kernel] Do not add compile-time dependencies for literals as defaults in `Application.compile_env/3` inside module attributes
-  * [Macro] Add `Macro.expand_literals/2` and `Macro.expand_literals/3`
-  * [System] Add `:close_stdin` to `System.shell/2`
-
-#### Mix
-
-  * [mix test] Accept `--all-warnings` option
-
-## 2. Bug fixes
-
-#### Elixir
-
-  * [Kernel] Fix misleading warning when `:uniq` is given in `for` comprehensions and the result is unused
-  * [Kernel] Improve error message for when there is a conflicting struct and ignoring module conflict
-  * [Kernel] Do not delete `@enforce_keys` attribute after `defstruct` declaration
-  * [Kernel] Do not crash the checker on modules with missing `:debug_info` chunk
-  * [Macro] Fix error in `Macro.to_string/2` when converting an AST with `:erlang.binary_to_atom/2`
-  * [String] Fix `String.split/3` and `String.next_grapheme/1` returning invalid results on invalid UTF-8 encoding
-  * [System] Do not close stdin by default in `System.shell/2`
-  * [URI] Do not return `uri.port` as `:undefined` in certain cases in `URI.new/1`
+  * [Calendar.ISO] Support negative dates in `Calendar.ISO`
+  * [Calendar] Add `Calendar.months_in_year/1` callback
+  * [Code] Add `Code.compile_file/2` that compiles files without leaving footprints on the system
+  * [Code] Add `Code.purge_compiler_modules/0` that purges any compiler module left behind. This is useful for live systems dynamically compiling code
+  * [Code] Add `Code.fetch_docs/1` that returns docs in the [EEP 48](http://erlang.org/eep/eeps/eep-0048.html) format
+  * [Date] Add `Date.months_in_year/1` function
+  * [DynamicSupervisor] Use the name of the `DynamicSupervisor` as the ID whenever possible
+  * [Exception] Provide "did you mean" suggestions on KeyError
+  * [Exception] Provide more information on ArithmeticError on Erlang/OTP 21+
+  * [Function] Add `Function` module with `capture/3`, `info/1` and `info/2` functions
+  * [GenServer] Support the new `handle_continue/2` callback on Erlang/OTP 21+
+  * [IO.ANSI] Add cursor movement to `IO.ANSI`
+  * [Kernel] Support adding arbitrary documentation metadata by passing a keyword list to `@doc`, `@moduledoc` and `@typedoc`
+  * [Kernel] Introduce `__STACKTRACE__` to retrieve the current stacktrace inside `catch`/`rescue` (this will be a requirement for Erlang/OTP 21+)
+  * [Kernel] Raise on unsafe variables in order to allow us to better track unused variables
+  * [Kernel] Warn when using `length` to check if a list is not empty on guards
+  * [Kernel] Add hints on mismatched `do`/`end` and others pairs
+  * [Kernel] Warn when comparing structs using the `>`, `<`, `>=` and `<=` operators
+  * [Kernel] Warn on unsupported nested comparisons such as `x < y < z`
+  * [Kernel] Warn if redefining documentation across clauses of the same definition
+  * [Kernel] Warn on unnecessary quotes around atoms, keywords and calls
+  * [Macro] Add `Macro.special_form?/2` and `Macro.operator?/2` that returns `true` if the given name/arity is a special form or operator respectively
+  * [Macro.Env] Add `Macro.Env.vars/1` and `Macro.Env.has_var?/2` that gives access to environment data without accessing private fields
+  * [Regex] Include endianness in the regex version. This allows regexes to be recompiled when an archive is installed in a system with a different endianness
+  * [Registry] Add `Registry.count/1` and `Registry.count_match/4`
+  * [String] Update to Unicode 11
+  * [StringIO] Add `StringIO.open/3`
+  * [System] Use ISO 8601 in `System.build_info/0`
 
 #### ExUnit
 
-  * [ExUnit.DocTest] Do not crash when both `:moduledoc` and functions are specified in `:only`
+  * [ExUnit.Assertion] Print the arguments in error reports when asserting on a function call. For example, if `assert is_list(arg)` fails, the argument will be shown in the report
+  * [ExUnit.Diff] Improve diffing of lists when one list is a subset of the other
+  * [ExUnit.DocTest] Show colored diffs on failed doctests
+  * [ExUnit.Formatter] Excluded tests, via the `--exclude` and `--only` flags, are now shown as "Excluded" in reports. Tests skipped via `@tag :skip` are now exclusively shown as "Skipped" and in yellow
 
 #### IEx
 
-  * [CLI] Fix invalid argument handling when `--no-pry` is given
-
-#### Mix
-
-  * [mix format] Do not cache inputs from `.formatter.exs` so they are properly re-evaluted on every call
-
-## v1.14.0 (2022-09-01)
-
-### 1. Enhancements
-
-#### EEx
-
-  * [EEx] Support multi-line comments to EEx via `<%!-- --%>`
-  * [EEx] Add `EEx.tokenize/2`
-
-#### Elixir
-
-  * [Access] Add `Access.slice/1`
-  * [Application] Add `Application.compile_env/4` and `Application.compile_env!/3` to read the compile-time environment inside macros
-  * [Calendar] Support ISO8601 basic format parsing with `DateTime.from_iso8601/2`
-  * [Calendar] Add `day`/`hour`/`minute` on `add`/`diff` across different calendar modules
-  * [Code] Add `:normalize_bitstring_modifiers` to `Code.format_string!/2`
-  * [Code] Emit deprecation and type warnings for invalid options in on `Code.compile_string/2` and `Code.compile_quoted/2`
-  * [Code] Warn if an outdated lexical tracker is given on eval
-  * [Code] Add `Code.env_for_eval/1` and `Code.eval_quoted_with_env/3`
-  * [Code] Improve stacktraces from eval operations on Erlang/OTP 25+
-  * [Code.Fragment] Add support for `__MODULE__` in several functions
-  * [Code.Fragment] Support surround and context suggestions across multiple lines
-  * [Enum] Allow slicing with steps in `Enum.slice/2`
-  * [File] Support `dereference_symlinks: true` in `File.cp/3` and `File.cp_r/3`
-  * [Float] Do not show floats in scientific notation if below `1.0e16` and the fractional value is precisely zero
-  * [Float] Add `Float.min_finite/0` and `Float.max_finite/0`
-  * [Inspect] Improve error reporting when there is a faulty implementation of the `Inspect` protocol
-  * [Inspect] Allow `:optional` when deriving the Inspect protocol for hiding fields that match their default value
-  * [Inspect] Inspect struct fields in the order they are declared in `defstruct`
-  * [Inspect] Use expression-based inspection for `Date.Range`, `MapSet`, and `Version.Requirement`
-  * [IO] Support `Macro.Env` and keywords as stacktrace definitions in `IO.warn/2`
-  * [IO] Add `IO.ANSI.syntax_colors/0` and related configuration to be shared across IEx and `dbg`
-  * [Kernel] Add new `dbg/0-2` macro
-  * [Kernel] Allow any guard expression as the size of a bitstring in a pattern match
-  * [Kernel] Allow composite types with pins as the map key in a pattern match
-  * [Kernel] Print escaped version of control chars when they show up as unexpected tokens
-  * [Kernel] Warn on confusable non-ASCII identifiers
-  * [Kernel] Add `..` as a nullary operator that returns `0..-1//1`
-  * [Kernel] Implement Unicode Technical Standard #39 recommendations. In particular, we warn for confusable scripts and restrict identifiers to single-scripts or highly restrictive mixed-scripts
-  * [Kernel] Automatically perform NFC conversion of identifiers
-  * [Kernel] Add `binary_slice/2` and `binary_slice/3`
-  * [Kernel] Lazily expand module attributes to avoid compile-time deps
-  * [Kernel] Automatically cascade `generated: true` annotations on macro expansion
-  * [Keyword] Add `Keyword.from_keys/2` and `Keyword.replace_lazy/3`
-  * [List] Add `List.keysort/3` with support for a `sorter` function
-  * [Macro] Add `Macro.classify_atom/1` and `Macro.inspect_atom/2`
-  * [Macro] Add `Macro.path/2`
-  * [Macro.Env] Add `Macro.Env.prune_compile_info/1`
-  * [Map] Add `Map.from_keys/2` and `Map.replace_lazy/3`
-  * [MapSet] Add `MapSet.filter/2`, `MapSet.reject/2`, and `MapSet.symmetric_difference/2`
-  * [Node] Add `Node.spawn_monitor/2` and `Node.spawn_monitor/4`
-  * [Module] Support new `@after_verify` attribute for executing code whenever a module is verified
-  * [PartitionSupervisor] Add `PartitionSupervisor` that starts multiple isolated partitions of the same child for scalability
-  * [Path] Add `Path.safe_relative/1` and `Path.safe_relative_to/2`
-  * [Registry] Add `Registry.count_select/2`
-  * [Stream] Add `Stream.duplicate/2` and `Stream.transform/5`
-  * [String] Support empty lookup lists in `String.replace/3`, `String.split/3`, and `String.splitter/3`
-  * [String] Allow slicing with steps in `String.slice/2`
-  * [Task] Add `:zip_input_on_exit` option to `Task.async_stream/3`
-  * [Task] Store `:mfa` in the `Task` struct for reflection purposes
-  * [URI] Add `URI.append_query/2`
-  * [Version] Add `Version.to_string/1`
-  * [Version] Colorize `Version.Requirement` source in the `Inspect` protocol
-
-#### ExUnit
-
-  * [ExUnit] Add `ExUnit.Callbacks.start_link_supervised!/2`
-  * [ExUnit] Add `ExUnit.run/1` to rerun test modules
-  * [ExUnit] Colorize summary in yellow with message when all tests are excluded
-  * [ExUnit] Display friendly error when test name is too long
-
-#### IEx
-
-  * [IEx] Evaluate `--dot-iex` line by line
-  * [IEx] Add line-by-line evaluation of IEx breakpoints
-  * [IEx.Autocomplete] Autocomplete bitstrings modifiers (after `::` inside `<<...>>`)
-  * [IEx.Helpers] Allow an atom to be given to `pid/1`
-  * [IEx.Helpers] Support sigils in `h/1`
+  * [IEx.Helpers] Add `use_if_available/2`
+  * [IEx.Helpers] Allow `force: true` option in `recompile/1`
+  * [IEx.Helpers] Add `:allocators` pane to `runtime_info/1`
+  * [IEx.Helpers] Show documentation metadata in `h/1` helpers
 
 #### Logger
 
-  * [Logger] Add `Logger.put_process_level/2`
+  * [Logger] Ensure nil metadata is always pruned
+  * [Logger] Only evaluate Logger macro arguments when the message will be logged
+  * [Logger] Add `:compile_time_purge_matching` to purge logger calls that match certain compile time metadata, such as module names and application names
+  * [Logger] Log to `:stderr` if a backend fails and there are no other backends
+  * [Logger] Allow translators to return custom metadata
+  * [Logger] Return `:crash_reason`, `:initial_call` and `:registered_name` as metadata in crash reports coming from Erlang/OTP
 
 #### Mix
 
-  * [Mix] Add `:config_path` and `:lockfile` options to `Mix.install/2`
-  * [mix compile] Add `--no-optional-deps` to skip optional dependencies to test compilation works without optional dependencies
-  * [mix compile] Include column information on error diagnostics when possible
-  * [mix deps] `Mix.Dep.Converger` now tells which deps formed a cycle
-  * [mix do] Support `--app` option to restrict recursive tasks in umbrella projects
-  * [mix do] Allow using `+` as a task separator instead of comma
-  * [mix format] Support filename in `mix format -` when reading from stdin
-  * [mix format] Compile if `mix format` plugins are missing
-  * [mix new] Do not allow projects to be created with application names that conflict with multi-arg Erlang VM switches
-  * [mix profile] Return the return value of the profiled function
-  * [mix release] Make BEAM compression opt-in
-  * [mix release] Let `:runtime_config_path` accept `false` to skip the `config/runtime.exs`
-  * [mix test] Improve error message when suite fails due to coverage
-  * [mix test] Support `:test_elixirc_options` and default to not generating docs nor debug info chunk for tests
-  * [mix xref] Support `--group` flag in `mix xref graph`
+  * [mix archive.install] Add support for the Hex organization via `--organization`
+  * [mix archive.uninstall] Support `--force` flag
+  * [mix compile] Improve support for external build tools such as `rebar`
+  * [mix deps] Include `override: true` in rebar dependencies to make the behaviour closer to how rebar3 works (although diverged deps are still marked as diverged)
+  * [mix escript.install] Add support for the Hex organization via `--organization`
+  * [mix escript.uninstall] Support `--force` flag
+  * [mix help] Also list aliases
+  * [mix local] Use ipv6 with auto fallback to ipv4 when downloading data
+  * [mix profile] Allow all profiling tasks to run programatically
+  * [mix test] Add `--failed` option that only runs previously failed tests
+  * [mix test] Print coverage summary by default when the `--cover` flag is given
+  * [Mix.Project] Add `Mix.Project.clear_deps_cache/0`
+  * [Mix.Project] Add `Mix.Project.config_mtime/0` that caches the config mtime values to avoid filesystem access
 
 ### 2. Bug fixes
 
 #### Elixir
 
-  * [Calendar] Handle widths with "0" in them in `Calendar.strftime/3`
-  * [CLI] Improve errors on incorrect `--rpc-eval` usage
-  * [CLI] Return proper exit code on Windows
-  * [Code] Do not emit warnings when formatting code
-  * [Enum] Allow slices to overflow on both starting and ending positions
-  * [Kernel] Do not allow restricted characters in identifiers according to UTS39
-  * [Kernel] Define `__exception__` field as `true` when expanding exceptions in typespecs
-  * [Kernel] Warn if any of `True`, `False`, and `Nil` aliases are used
-  * [Kernel] Warn on underived `@derive` attributes
-  * [Kernel] Remove compile-time dependency from `defimpl :for`
-  * [Kernel] Track all arities on imported functions
-  * [Kernel] Fix equality in guards for dynamic ranges without steps
-  * [Module] Fix loop while unifying type variables
-  * [Protocol] Warn if a protocol has no definitions
-  * [Regex] Show list options when inspecting a Regex manually defined with `Regex.compile/2`
-  * [String] Allow slices to overflow on both starting and ending positions  
-  * [System] Raise non-generic exception on missing env in `System.fetch_env!/1` to mirror map operations
+  * [IO.ANSI.Docs] Fix table column alignment when converting docs to ANSI escapes
+  * [Code] Ensure `string_to_quoted` returns error tuples instead of raising in certain constructs
+  * [Code.Formatter] Consistently format keyword lists in function calls with and without parens
+  * [Code.Formatter] Do not break after `->` when there are only comments and one-line clauses
+  * [File] Allow the `:trim_bom` option to be used with `:encoding`
+  * [Kernel] Raise on unsafe variables as some of the code emitted with unsafe variables would not correctly propagate variables or would disable tail call optimization semantics
+  * [Kernel] Do not crash on dynamic sizes in binary generators with collectable into in comprehensions
+  * [Kernel] Do not crash on literals with non-unary size in binary generators with collectable into in comprehensions
+  * [Task] Improve error reports and exit reasons for failed tasks on Erlang/OTP 20+
 
 #### ExUnit
 
-  * [ExUnit] Do not crash when diffing unknown bindings in guards
-  * [ExUnit] Properly print diffs when comparing improper lists with strings at the tail position
-  * [ExUnit] Add short hash to `tmp_dir` in ExUnit to avoid test name collision
-  * [ExUnit] Do not store logs in the CLI formatter (this reduces memory usage for suites with `capture_log`)
-  * [ExUnit] Run `ExUnit.after_suite/1` callback even when no tests run
-  * [ExUnit] Fix scenario where `setup` with imported function from within `describe` failed to compile
-
-#### IEx
-
-  * [IEx] Disallow short-hand pipe after matches
-  * [IEx] Fix `exports/1` in IEx for long function names
+  * [ExUnit.Case] Raise proper error if `@tag` and `@moduletag` are used before `use ExUnit.Case`
+  * [ExUnit.Case] Raise proper error if `@describetag` is used outside of `describe/2` blocks
+  * [ExUnit.DocTest] Emit proper assertion error on doctests with invalid UTF-8
 
 #### Mix
 
-  * [mix compile.elixir] Fix `--warnings-as-errors` when used with `--all-warnings`
-  * [mix compile.elixir] Ensure semantic recompilation cascades to path dependencies
-  * [mix compile.elixir] Lock the compiler to avoid concurrent usage
-  * [mix format] Do not add new lines if the formatted file is empty
-  * [mix format] Properly compile dependencies on `mix format`
-  * [mix release] Only set `RELEASE_MODE` after `env.{sh,bat}` are executed
-  * [mix release] Allow application mode configuration to cascade to dependencies
-  * [mix xref] Do not emit already consolidated warnings during `mix xref trace`
-  * [Mix] Do not start apps with `runtime: false` on `Mix.install/2`
+  * [mix archive.install] Fetch optional dependencies when installing an archive from Git/Hex
+  * [mix compile] Properly track config files in umbrella projects and recompile when any relevant umbrella configuration changes
+  * [mix deps] Ensure the same dependency from different SCMs are tagged as diverged when those SCMs are remote and non-remote
+  * [mix deps] Ensure we re-run dependency resolution when overriding a skipped dep in umbrella
+  * [mix deps.compile] Perform clean builds for dependencies on outdated locks to avoid old modules from affecting future compilation
+  * [mix escript.install] Fetch optional dependencies when installing an escript from Git/Hex
 
-### 3. Soft deprecations (no warnings emitted)
+### 3. Soft-deprecations (no warnings emitted)
 
 #### Elixir
 
-  * [File] Passing a callback as third argument to `File.cp/3` and `File.cp_r/3` is deprecated.
-    Instead pass the callback the `:on_conflict` key of a keyword list
-
-#### EEx
-
-  * [EEx] Using `<%# ... %>` for comments is deprecated. Please use `<% # ... %>` or the new multi-line comments with `<%!-- ... --%>`
+  * [Code] Deprecate `Code.load_file/2` in favor of `Code.compile_file/2`
+  * [Code] Deprecate `Code.loaded_files/0` in favor of `Code.required_files/0`
+  * [Code] Deprecate `Code.unload_files/1` in favor of `Code.unrequire_files/1`
 
 #### Logger
 
-  * [Logger] Deprecate `Logger.enable/1` and `Logger.disable/1` in favor of `Logger.put_process_level/2`
+  * [Logger] `compile_time_purge_level` is deprecated in favor of `compile_time_purge_matching`
 
-#### Mix
-
-  * [mix cmd] The `--app` option in `mix cmd CMD` is deprecated in favor of the more efficient `mix do --app app cmd CMD`
-
-### 4. Hard deprecations
+### 4. Hard-deprecations
 
 #### Elixir
 
-  * [Application] Calling `Application.get_env/3` and friends in the module body is now discouraged, use `Application.compile_env/3` instead
-  * [Bitwise] `use Bitwise` is deprecated, use `import Bitwise` instead
-  * [Bitwise] `~~~` is deprecated in favor of `bnot` for clarity
-  * [Kernel.ParallelCompiler] Returning a list or two-element tuple from `:each_cycle` is deprecated, return a `{:compile | :runtime, modules, warnings}` tuple instead
-  * [Kernel] Deprecate the operator `<|>` to avoid ambiguity with upcoming extended numerical operators
-  * [String] Deprecate passing a binary compiled pattern to `String.starts_with?/2`
+  * [Code] `Code.get_docs/2` is deprecated in favor of `Code.fetch_docs/1`
+  * [Enum] `Enum.chunk/2/3/4` is deprecated in favor of `Enum.chunk_every/2/3/4` - notice `chunk_every` does not discard incomplete chunks by default
+  * [GenServer] Warn if `super` is used in any of the GenServer callbacks
+  * [Kernel] `not left in right` is ambiguous and is deprecated in favor of `left not in right`
+  * [Kernel] Warn on confusing operator sequences, such as `1+++1` meaning `1 ++ +1` or `........` meaning `... .. ...`
+  * [OptionParser] Deprecate dynamic option parser mode that depended on atoms to be previously loaded and therefore behaved inconsistently
+  * [Stream] `Stream.chunk/2/3/4` is deprecated in favor of `Stream.chunk_every/2/3/4` - notice `chunk_every` does not discard incomplete chunks by default
 
-#### Logger
+## v1.6
 
-  * [Logger] Deprecate `$levelpad` on message formatting
-
-#### Mix
-
-  * [Mix] `Mix.Tasks.Xref.calls/1` is deprecated in favor of compilation tracers
-
-### 5. Backwards incompatible changes
-
-#### Mix
-
-  * [mix local.rebar] Remove support for rebar2, which has not been updated in 5 years, and is no longer supported on recent Erlang/OTP versions
-
-## v1.13
-
-The CHANGELOG for v1.13 releases can be found [in the v1.13 branch](https://github.com/elixir-lang/elixir/blob/v1.13/CHANGELOG.md).
+The CHANGELOG for v1.6 releases can be found [in the v1.6 branch](https://github.com/elixir-lang/elixir/blob/v1.6/CHANGELOG.md).

CODE_OF_CONDUCT.md

@@ -13,23 +13,17 @@ The goal of the Code of Conduct is to specify a baseline standard of behavior so
 These are the values Elixir developers should aspire to:
 
   * Be friendly and welcoming
-  * Be kind
+  * Be patient
     * Remember that people have varying communication styles and that not everyone is using their native language. (Meaning and tone can be lost in translation.)
-    * Interpret the arguments of others in good faith, do not seek to disagree.
-    * When we do disagree, try to understand why.
   * Be thoughtful
     * Productive communication requires effort. Think about how your words will be interpreted.
     * Remember that sometimes it is best to refrain entirely from commenting.
   * Be respectful
     * In particular, respect differences of opinion. It is important that we resolve disagreements and differing views constructively.
-  * Be constructive
-    * Avoid derailing: stay on topic; if you want to talk about something else, start a new conversation.
-    * Avoid unconstructive criticism: don't merely decry the current state of affairs; offer — or at least solicit — suggestions as to how things may be improved.
-    * Avoid harsh words and stern tone: we are all aligned towards the well-being of the community and the progress of the ecosystem. Harsh words exclude, demotivate, and lead to unnecessary conflict.
-    * Avoid snarking (pithy, unproductive, sniping comments).
-    * Avoid microaggressions (brief and commonplace verbal, behavioral and environmental indignities that communicate hostile, derogatory or negative slights and insults towards a project, person or group).
-  * Be responsible
-    * What you say and do matters. Take responsibility for your words and actions, including their consequences, whether intended or otherwise.
+  * Avoid destructive behavior
+    * Derailing: stay on topic; if you want to talk about something else, start a new conversation.
+    * Unconstructive criticism: don't merely decry the current state of affairs; offer (or at least solicit) suggestions as to how things may be improved.
+    * Snarking (pithy, unproductive, sniping comments).
 
 The following actions are explicitly forbidden:
 
@@ -45,13 +39,13 @@ If you participate in or contribute to the Elixir ecosystem in any way, you are
 
 Explicit enforcement of the Code of Conduct applies to the official mediums operated by the Elixir project:
 
-* The [official GitHub projects][1] and code reviews.
+* The official GitHub projects and code reviews.
 * The official elixir-lang mailing lists.
-* The **[#elixir][2]** IRC channel on [Libera.Chat][3].
+* The #elixir-lang IRC channel on Freenode.
 
-Other Elixir activities (such as conferences, meetups, and unofficial forums) are encouraged to adopt this Code of Conduct. Such groups must provide their own contact information.
+Other Elixir activities (such as conferences, meetups, and other unofficial forums) are encouraged to adopt this Code of Conduct. Such groups must provide their own contact information.
 
-Project maintainers may block, remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct.
+Project maintainers may remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct.
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by emailing: elixir-lang-conduct@googlegroups.com. All complaints will be reviewed and investigated and will result in a response that is deemed necessary and appropriate to the circumstances. **All reports will be kept confidential**.
 
@@ -59,8 +53,4 @@ Instances of abusive, harassing, or otherwise unacceptable behavior may be repor
 
 ## Acknowledgements
 
-This document was based on the Code of Conduct from the Go project (dated Sep/2021) and the Contributor Covenant (v1.4).
-
-[1]: https://github.com/elixir-lang/
-[2]: https://web.libera.chat/#elixir
-[3]: https://libera.chat/
+This document was based on the Code of Conduct from the Go project with parts derived from Django's Code of Conduct, Rust's Code of Conduct and the Contributor Covenant.

ISSUE_TEMPLATE.md

@@ -0,0 +1,18 @@
+### Precheck
+
+* Do not use the issues tracker for help or support (try Elixir Forum, Stack Overflow, IRC, etc.)
+* For proposing a new feature, please start a discussion on the Elixir Core mailing list
+* For bugs, do a quick search and make sure the bug has not yet been reported
+* Finally, be nice and have fun!
+
+### Environment
+
+* Elixir & Erlang/OTP versions (elixir --version): 
+* Operating system: 
+
+### Current behavior
+
+Include code samples, errors and stacktraces if appropriate.
+
+### Expected behavior
+

LICENSE

@@ -174,3 +174,28 @@
       of your accepting any such warranty or additional liability.
 
    END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "{}"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright 2012 Plataformatec
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

Makefile

@@ -1,13 +1,8 @@
 PREFIX ?= /usr/local
-TEST_FILES ?= "*_test.exs"
 SHARE_PREFIX ?= $(PREFIX)/share
-MAN_PREFIX ?= $(SHARE_PREFIX)/man
-CANONICAL := 1.14/
-CANONICAL ?= main/
-DOCS_FORMAT ?= html
-ELIXIRC := bin/elixirc --ignore-module-conflict $(ELIXIRC_OPTS)
+CANONICAL := v1.7/
+ELIXIRC := bin/elixirc --verbose --ignore-module-conflict
 ERLC := erlc -I lib/elixir/include
-ERL_MAKE := if [ -n "$(ERLC_OPTS)" ]; then ERL_COMPILER_OPTIONS=$(ERLC_OPTS) erl -make; else erl -make; fi
 ERL := erl -I lib/elixir/include -noshell -pa lib/elixir/ebin
 GENERATE_APP := $(CURDIR)/lib/elixir/generate_app.escript
 VERSION := $(strip $(shell cat VERSION))
@@ -20,18 +15,16 @@ INSTALL_DATA = $(INSTALL) -m644
 INSTALL_PROGRAM = $(INSTALL) -m755
 GIT_REVISION = $(strip $(shell git rev-parse HEAD 2> /dev/null ))
 GIT_TAG = $(strip $(shell head="$(call GIT_REVISION)"; git tag --points-at $$head 2> /dev/null | tail -1) )
-SOURCE_DATE_EPOCH_PATH = lib/elixir/tmp/ebin_reproducible
-SOURCE_DATE_EPOCH_FILE = $(SOURCE_DATE_EPOCH_PATH)/SOURCE_DATE_EPOCH
 
-.PHONY: install compile erlang elixir unicode app build_plt clean_plt dialyze test check_reproducible clean clean_residual_files format install_man clean_man docs Docs.zip Precompiled.zip zips
+.PHONY: install compile erlang elixir unicode app build_plt clean_plt dialyze test clean clean_residual_files install_man clean_man docs Docs.zip Precompiled.zip zips
 .NOTPARALLEL: compile
 
 #==> Functions
 
 define CHECK_ERLANG_RELEASE
-	erl -noshell -eval '{V,_} = string:to_integer(erlang:system_info(otp_release)), io:fwrite("~s", [is_integer(V) and (V >= 23)])' -s erlang halt | grep -q '^true'; \
+	erl -noshell -eval '{V,_} = string:to_integer(erlang:system_info(otp_release)), io:fwrite("~s", [is_integer(V) and (V >= 19)])' -s erlang halt | grep -q '^true'; \
 		if [ $$? != 0 ]; then \
-		  echo "At least Erlang/OTP 23.0 is required to build Elixir"; \
+		  echo "At least Erlang/OTP 19.0 is required to build Elixir"; \
 		  exit 1; \
 		fi
 endef
@@ -40,7 +33,11 @@ define APP_TEMPLATE
 $(1): lib/$(1)/ebin/Elixir.$(2).beam lib/$(1)/ebin/$(1).app
 
 lib/$(1)/ebin/$(1).app: lib/$(1)/mix.exs
-	$(Q) cd lib/$(1) && ../../bin/elixir -e 'Mix.start(:permanent, [])' -r mix.exs -e 'Mix.Task.run("compile.app", ~w[--compile-path ebin])'
+	$(Q) mkdir -p lib/$(1)/_build/shared/lib/$(1)
+	$(Q) cp -R lib/$(1)/ebin lib/$(1)/_build/shared/lib/$(1)/
+	$(Q) cd lib/$(1) && ../../bin/elixir -e 'Mix.start(:permanent, [])' -r mix.exs -e 'Mix.Task.run("compile.app")'
+	$(Q) cp lib/$(1)/_build/shared/lib/$(1)/ebin/$(1).app lib/$(1)/ebin/$(1).app
+	$(Q) rm -rf lib/$(1)/_build
 
 lib/$(1)/ebin/Elixir.$(2).beam: $(wildcard lib/$(1)/lib/*.ex) $(wildcard lib/$(1)/lib/*/*.ex) $(wildcard lib/$(1)/lib/*/*/*.ex)
 	@ echo "==> $(1) (compile)"
@@ -48,20 +45,8 @@ lib/$(1)/ebin/Elixir.$(2).beam: $(wildcard lib/$(1)/lib/*.ex) $(wildcard lib/$(1
 	$(Q) cd lib/$(1) && ../../$$(ELIXIRC) "lib/**/*.ex" -o ebin
 
 test_$(1): compile $(1)
-	@ echo "==> $(1) (ex_unit)"
-	$(Q) cd lib/$(1) && ../../bin/elixir -r "test/test_helper.exs" -pr "test/**/$(TEST_FILES)";
-endef
-
-define WRITE_SOURCE_DATE_EPOCH
-$(shell mkdir -p $(SOURCE_DATE_EPOCH_PATH) && bin/elixir -e \
-  'IO.puts System.build_info()[:date] \
-   |> DateTime.from_iso8601() \
-   |> elem(1) \
-   |> DateTime.to_unix()' > $(SOURCE_DATE_EPOCH_FILE))
-endef
-
-define READ_SOURCE_DATE_EPOCH
-$(strip $(shell cat $(SOURCE_DATE_EPOCH_FILE)))
+	@ echo "==> $(1) (exunit)"
+	$(Q) cd lib/$(1) && ../../bin/elixir -r "test/test_helper.exs" -pr "test/**/*_test.exs";
 endef
 
 #==> Compilation tasks
@@ -77,14 +62,14 @@ compile: erlang $(APP) elixir
 
 erlang: $(PARSER)
 	$(Q) if [ ! -f $(APP) ]; then $(call CHECK_ERLANG_RELEASE); fi
-	$(Q) cd lib/elixir && mkdir -p ebin && $(ERL_MAKE)
+	$(Q) cd lib/elixir && mkdir -p ebin && erl -make
 
 $(PARSER): lib/elixir/src/elixir_parser.yrl
 	$(Q) erlc -o $@ +'{verbose,true}' +'{report,true}' $<
 
 # Since Mix depends on EEx and EEx depends on Mix,
 # we first compile EEx without the .app file,
-# then Mix, and then compile EEx fully
+# then Mix and then compile EEx fully
 elixir: stdlib lib/eex/ebin/Elixir.EEx.beam mix ex_unit logger eex iex
 
 stdlib: $(KERNEL) VERSION
@@ -93,10 +78,11 @@ $(KERNEL): lib/elixir/lib/*.ex lib/elixir/lib/*/*.ex lib/elixir/lib/*/*/*.ex
 		echo "==> bootstrap (compile)"; \
 		$(ERL) -s elixir_compiler bootstrap -s erlang halt; \
 	fi
-	$(Q) "$(MAKE)" unicode
 	@ echo "==> elixir (compile)";
+	$(Q) cd lib/elixir && ../../$(ELIXIRC) "lib/kernel.ex" -o ebin;
 	$(Q) cd lib/elixir && ../../$(ELIXIRC) "lib/**/*.ex" -o ebin;
-	$(Q) "$(MAKE)" app
+	$(Q) $(MAKE) unicode
+	$(Q) $(MAKE) app
 
 app: $(APP)
 $(APP): lib/elixir/src/elixir.app.src lib/elixir/ebin VERSION $(GENERATE_APP)
@@ -106,7 +92,7 @@ unicode: $(UNICODE)
 $(UNICODE): lib/elixir/unicode/*
 	@ echo "==> unicode (compile)";
 	$(Q) $(ELIXIRC) lib/elixir/unicode/unicode.ex -o lib/elixir/ebin;
-	$(Q) $(ELIXIRC) lib/elixir/unicode/security.ex -o lib/elixir/ebin;
+	$(Q) $(ELIXIRC) lib/elixir/unicode/properties.ex -o lib/elixir/ebin;
 	$(Q) $(ELIXIRC) lib/elixir/unicode/tokenizer.ex -o lib/elixir/ebin;
 
 $(eval $(call APP_TEMPLATE,ex_unit,ExUnit))
@@ -128,39 +114,13 @@ install: compile
 	$(Q) for file in "$(DESTDIR)$(PREFIX)"/$(LIBDIR)/elixir/bin/*; do \
 		ln -sf "../$(LIBDIR)/elixir/bin/$${file##*/}" "$(DESTDIR)$(PREFIX)/$(BINDIR)/"; \
 	done
-	"$(MAKE)" install_man
-
-check_reproducible: compile
-	$(Q) echo "==> Checking for reproducible builds..."
-	$(Q) rm -rf lib/*/tmp/ebin_reproducible/
-	$(call WRITE_SOURCE_DATE_EPOCH)
-	$(Q) mkdir -p lib/elixir/tmp/ebin_reproducible/ \
-	              lib/eex/tmp/ebin_reproducible/ \
-	              lib/ex_unit/tmp/ebin_reproducible/ \
-	              lib/iex/tmp/ebin_reproducible/ \
-	              lib/logger/tmp/ebin_reproducible/ \
-	              lib/mix/tmp/ebin_reproducible/
-	$(Q) mv lib/elixir/ebin/* lib/elixir/tmp/ebin_reproducible/
-	$(Q) mv lib/eex/ebin/* lib/eex/tmp/ebin_reproducible/
-	$(Q) mv lib/ex_unit/ebin/* lib/ex_unit/tmp/ebin_reproducible/
-	$(Q) mv lib/iex/ebin/* lib/iex/tmp/ebin_reproducible/
-	$(Q) mv lib/logger/ebin/* lib/logger/tmp/ebin_reproducible/
-	$(Q) mv lib/mix/ebin/* lib/mix/tmp/ebin_reproducible/
-	SOURCE_DATE_EPOCH=$(call READ_SOURCE_DATE_EPOCH) "$(MAKE)" compile
-	$(Q) echo "Diffing..."
-	$(Q) bin/elixir lib/elixir/diff.exs lib/elixir/ebin/ lib/elixir/tmp/ebin_reproducible/
-	$(Q) bin/elixir lib/elixir/diff.exs lib/eex/ebin/ lib/eex/tmp/ebin_reproducible/
-	$(Q) bin/elixir lib/elixir/diff.exs lib/ex_unit/ebin/ lib/ex_unit/tmp/ebin_reproducible/
-	$(Q) bin/elixir lib/elixir/diff.exs lib/iex/ebin/ lib/iex/tmp/ebin_reproducible/
-	$(Q) bin/elixir lib/elixir/diff.exs lib/logger/ebin/ lib/logger/tmp/ebin_reproducible/
-	$(Q) bin/elixir lib/elixir/diff.exs lib/mix/ebin/ lib/mix/tmp/ebin_reproducible/
-	$(Q) echo "Builds are reproducible"
+	$(MAKE) install_man
 
 clean:
 	rm -rf ebin
 	rm -rf lib/*/ebin
 	rm -rf $(PARSER)
-	$(Q) "$(MAKE)" clean_residual_files
+	$(Q) $(MAKE) clean_residual_files
 
 clean_elixir:
 	$(Q) rm -f lib/*/ebin/Elixir.*.beam
@@ -173,47 +133,47 @@ clean_residual_files:
 	rm -rf lib/mix/test/fixtures/git_rebar/
 	rm -rf lib/mix/test/fixtures/git_repo/
 	rm -rf lib/mix/test/fixtures/git_sparse_repo/
-	rm -rf lib/mix/test/fixtures/archive/ebin/
 	rm -f erl_crash.dump
-	$(Q) "$(MAKE)" clean_man
+	$(Q) $(MAKE) clean_man
 
 #==> Documentation tasks
 
 LOGO_PATH = $(shell test -f ../docs/logo.png && echo "--logo ../docs/logo.png")
-SOURCE_REF = $(shell tag="$(call GIT_TAG)" revision="$(call GIT_REVISION)"; echo "$${tag:-$$revision}")
-COMPILE_DOCS = CANONICAL=$(CANONICAL) bin/elixir ../ex_doc/bin/ex_doc "$(1)" "$(VERSION)" "lib/$(2)/ebin" --main "$(3)" --source-url "https://github.com/elixir-lang/elixir" --source-ref "$(call SOURCE_REF)" $(call LOGO_PATH) --output doc/$(2) --canonical "https://hexdocs.pm/$(2)/$(CANONICAL)" --homepage-url "https://elixir-lang.org/docs.html" --formatter "$(DOCS_FORMAT)" $(4)
+SOURCE_REF = $(shell tag="$(call GIT_TAG)" revision="$(call GIT_REVISION)"; echo "$${tag:-$$revision}\c")
+DOCS_FORMAT = html
+COMPILE_DOCS = bin/elixir ../ex_doc/bin/ex_doc "$(1)" "$(VERSION)" "lib/$(2)/ebin" -m "$(3)" -u "https://github.com/elixir-lang/elixir" --source-ref "$(call SOURCE_REF)" $(call LOGO_PATH) -o doc/$(2) -n https://hexdocs.pm/$(2)/$(CANONICAL) -p http://elixir-lang.org/docs.html -f "$(DOCS_FORMAT)" $(4)
 
 docs: compile ../ex_doc/bin/ex_doc docs_elixir docs_eex docs_mix docs_iex docs_ex_unit docs_logger
 
 docs_elixir: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (elixir)"
 	$(Q) rm -rf doc/elixir
-	$(call COMPILE_DOCS,Elixir,elixir,Kernel,--config "lib/elixir/docs.exs")
+	$(call COMPILE_DOCS,Elixir,elixir,Kernel,-c lib/elixir/docs.exs)
 
 docs_eex: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (eex)"
 	$(Q) rm -rf doc/eex
-	$(call COMPILE_DOCS,EEx,eex,EEx,--config "lib/mix/docs.exs")
+	$(call COMPILE_DOCS,EEx,eex,EEx)
 
 docs_mix: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (mix)"
 	$(Q) rm -rf doc/mix
-	$(call COMPILE_DOCS,Mix,mix,Mix,--config "lib/mix/docs.exs")
+	$(call COMPILE_DOCS,Mix,mix,Mix)
 
 docs_iex: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (iex)"
 	$(Q) rm -rf doc/iex
-	$(call COMPILE_DOCS,IEx,iex,IEx,--config "lib/mix/docs.exs")
+	$(call COMPILE_DOCS,IEx,iex,IEx)
 
 docs_ex_unit: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (ex_unit)"
 	$(Q) rm -rf doc/ex_unit
-	$(call COMPILE_DOCS,ExUnit,ex_unit,ExUnit,--config "lib/mix/docs.exs")
+	$(call COMPILE_DOCS,ExUnit,ex_unit,ExUnit)
 
 docs_logger: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (logger)"
 	$(Q) rm -rf doc/logger
-	$(call COMPILE_DOCS,Logger,logger,Logger,--config "lib/mix/docs.exs")
+	$(call COMPILE_DOCS,Logger,logger,Logger)
 
 ../ex_doc/bin/ex_doc:
 	@ echo "ex_doc is not found in ../ex_doc as expected. See README for more information."
@@ -222,18 +182,27 @@ docs_logger: compile ../ex_doc/bin/ex_doc
 #==> Zip tasks
 
 Docs.zip: docs
-	rm -f Docs.zip
-	zip -9 -r Docs.zip CHANGELOG.md doc NOTICE LICENSE README.md
-	@ echo "Docs file created $(CURDIR)/Docs.zip"
+	rm -f Docs-v$(VERSION).zip
+	zip -9 -r Docs-v$(VERSION).zip CHANGELOG.md doc NOTICE LICENSE README.md
+	@ echo "Docs file created $(CURDIR)/Docs-v$(VERSION).zip"
 
 Precompiled.zip: build_man compile
-	rm -f Precompiled.zip
-	zip -9 -r Precompiled.zip bin CHANGELOG.md lib/*/ebin lib/*/lib LICENSE man NOTICE README.md VERSION
-	@ echo "Precompiled file created $(CURDIR)/Precompiled.zip"
+	rm -f Precompiled-v$(VERSION).zip
+	zip -9 -r Precompiled-v$(VERSION).zip bin CHANGELOG.md lib/*/ebin lib/*/lib LICENSE man NOTICE README.md VERSION
+	@ echo "Precompiled file created $(CURDIR)/Precompiled-v$(VERSION).zip"
+
+zips: Precompiled.zip Docs.zip
+	@ echo ""
+	@ echo "## Checksums"
+	@ echo ""
+	@ shasum -a 1 < Precompiled-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Precompiled.zip SHA1:"
+	@ shasum -a 512 < Precompiled-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Precompiled.zip SHA512:"
+	@ shasum -a 1 < Docs-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Docs.zip SHA1:"
+	@ shasum -a 512 < Docs-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Docs.zip SHA512:"
+	@ echo ""
 
 #==> Test tasks
 
-# If you modify this task, please update .cirrus.yml accordingly
 test: test_formatted test_erlang test_elixir
 
 test_windows: test test_taskkill
@@ -246,19 +215,8 @@ TEST_ERL = lib/elixir/test/erlang
 TEST_EBIN = lib/elixir/test/ebin
 TEST_ERLS = $(addprefix $(TEST_EBIN)/, $(addsuffix .beam, $(basename $(notdir $(wildcard $(TEST_ERL)/*.erl)))))
 
-define FORMAT
-	$(Q) if [ "$(OS)" = "Windows_NT" ]; then \
-		cmd //C call ./bin/mix.bat format $(1); \
-	else \
-		bin/elixir bin/mix format $(1); \
-	fi
-endef
-
-format: compile
-	$(call FORMAT)
-
 test_formatted: compile
-	$(call FORMAT,--check-formatted)
+	bin/elixir bin/mix format --check-formatted
 
 test_erlang: compile $(TEST_ERLS)
 	@ echo "==> elixir (eunit)"
@@ -269,15 +227,15 @@ $(TEST_EBIN)/%.beam: $(TEST_ERL)/%.erl
 	$(Q) mkdir -p $(TEST_EBIN)
 	$(Q) $(ERLC) -o $(TEST_EBIN) $<
 
-test_elixir: test_stdlib test_ex_unit test_logger test_eex test_iex test_mix
+test_elixir: test_stdlib test_ex_unit test_logger test_mix test_eex test_iex
 
 test_stdlib: compile
-	@ echo "==> elixir (ex_unit)"
+	@ echo "==> elixir (exunit)"
 	$(Q) exec epmd & exit
 	$(Q) if [ "$(OS)" = "Windows_NT" ]; then \
-		cd lib/elixir && cmd //C call ../../bin/elixir.bat -r "test/elixir/test_helper.exs" -pr "test/elixir/**/$(TEST_FILES)"; \
+		cd lib/elixir && cmd //C call ../../bin/elixir.bat -r "test/elixir/test_helper.exs" -pr "test/elixir/**/*_test.exs"; \
 	else \
-		cd lib/elixir && ../../bin/elixir -r "test/elixir/test_helper.exs" -pr "test/elixir/**/$(TEST_FILES)"; \
+		cd lib/elixir && ../../bin/elixir -r "test/elixir/test_helper.exs" -pr "test/elixir/**/*_test.exs"; \
 	fi
 
 #==> Dialyzer tasks
@@ -287,7 +245,7 @@ PLT = .elixir.plt
 
 $(PLT):
 	@ echo "==> Building PLT with Elixir's dependencies..."
-	$(Q) dialyzer --output_plt $(PLT) --build_plt --apps erts kernel stdlib compiler syntax_tools parsetools tools ssl inets crypto runtime_tools ftp tftp mnesia public_key asn1 sasl
+	$(Q) dialyzer --output_plt $(PLT) --build_plt --apps erts kernel stdlib compiler syntax_tools parsetools tools ssl inets
 
 clean_plt:
 	$(Q) rm -f $(PLT)
@@ -296,7 +254,7 @@ build_plt: clean_plt $(PLT)
 
 dialyze: compile $(PLT)
 	@ echo "==> Dialyzing Elixir..."
-	$(Q) dialyzer -pa lib/elixir/ebin --plt $(PLT) $(DIALYZER_OPTS) lib/*/ebin
+	$(Q) dialyzer --plt $(PLT) $(DIALYZER_OPTS) lib/*/ebin
 
 #==> Man page tasks
 
@@ -321,9 +279,9 @@ clean_man:
 	rm -f man/iex.1.bak
 
 install_man: build_man
-	$(Q) mkdir -p $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/elixir.1  $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/elixirc.1 $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/iex.1     $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/mix.1     $(DESTDIR)$(MAN_PREFIX)/man1
-	"$(MAKE)" clean_man
+	$(Q) mkdir -p $(DESTDIR)$(SHARE_PREFIX)/man/man1
+	$(Q) $(INSTALL_DATA) man/elixir.1  $(DESTDIR)$(SHARE_PREFIX)/man/man1
+	$(Q) $(INSTALL_DATA) man/elixirc.1 $(DESTDIR)$(SHARE_PREFIX)/man/man1
+	$(Q) $(INSTALL_DATA) man/iex.1     $(DESTDIR)$(SHARE_PREFIX)/man/man1
+	$(Q) $(INSTALL_DATA) man/mix.1     $(DESTDIR)$(SHARE_PREFIX)/man/man1
+	$(MAKE) clean_man

NOTICE

@@ -1,7 +1,9 @@
 LEGAL NOTICE INFORMATION
 ------------------------
 
-All the files in this distribution are copyright to the terms below.
+All the files in this distribution are copyright (c) 2012 Plataformatec
+covered under Elixir's license (see the file LICENSE) except the cases
+below.
 
 == lib/elixir/src/elixir_parser.erl (generated by build scripts)
 
@@ -11,24 +13,7 @@ Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
-    https://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-
-== All other files
-
-Copyright 2012 Plataformatec
-Copyright 2021 The Elixir Team
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-   https://www.apache.org/licenses/LICENSE-2.0
+    http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,

README.md

@@ -1,82 +1,16 @@
-<img src="https://github.com/elixir-lang/elixir-lang.github.com/raw/main/images/logo/logo.png#gh-light-mode-only" width="200" alt="Elixir">
-<img src="https://github.com/elixir-lang/elixir-lang.github.com/raw/main/images/logo/logo-dark.png#gh-dark-mode-only" width="200" alt="Elixir">
+![Elixir](https://github.com/elixir-lang/elixir-lang.github.com/raw/master/images/logo/logo.png)
+=========
+[![Travis build](https://secure.travis-ci.org/elixir-lang/elixir.svg?branch=master
+"Build Status")](https://travis-ci.org/elixir-lang/elixir)
 
-[![CI](https://github.com/elixir-lang/elixir/workflows/CI/badge.svg?branch=main)](https://github.com/elixir-lang/elixir/actions?query=branch%3Amain+workflow%3ACI) [![Build status](https://api.cirrus-ci.com/github/elixir-lang/elixir.svg?branch=main)](https://cirrus-ci.com/github/elixir-lang/elixir)
-
-Elixir is a dynamic, functional language designed for building scalable
-and maintainable applications.
+Elixir is a dynamic, functional language designed for building scalable and maintainable applications.
 
 For more about Elixir, installation and documentation,
-[check Elixir's website](https://elixir-lang.org/).
-
-## Policies
-
-New releases are announced in the [announcement mailing list][8].
-You can subscribe by sending an email to elixir-lang-ann+subscribe@googlegroups.com
-and replying to the confirmation email.
-
-All security releases [will be tagged with `[security]`][10]. For more
-information, please read our [Security Policy][9].
-
-All interactions in our official communication channels follow our
-[Code of Conduct][1].
-
-## Bug reports
-
-For reporting bugs, [visit our issue tracker][2] and follow the steps
-for reporting a new issue. **Please disclose security vulnerabilities
-privately at elixir-security@googlegroups.com**.
-
-## Issues tracker management
-
-All currently open bugs related to the Elixir repository are listed
-in the issues tracker. The Elixir team uses the issues tracker to focus
-on *actionable items*, including planned enhancements in the short- and
-medium-term. We also do our best to label entries for clarity and to ease
-collaboration.
-
-Our *actionable item policy* has some important consequences, such as:
-
-  * Proposing new features as well as request for support, help, and
-    guidance must be done in their own spaces, detailed next.
-
-  * Issues where we have identified to be outside of Elixir scope,
-    such as a bug upstream, will be closed (and requested to be moved
-    elsewhere if appropriate).
-
-  * We actively close unrelated and non-actionable issues to keep the
-    issues tracker tidy. However, we may get things wrong from time to
-    time, so we are glad to revisit issues and reopen if necessary.
-
-Keep the tone positive and be kind! For more information, see the
-[Code of Conduct][1].
-
-### Proposing new features
-
-For proposing new features, please start a discussion in the
-[Elixir Core mailing list][3]. Keep in mind that it is your responsibility
-to argue and explain why a feature is useful and how it will impact the
-codebase and the community.
-
-Once a proposal is accepted, it will be added to [the issue tracker][2].
-Features and bug fixes that have already been merged and will be included
-in the next release are then "closed" and added to the [changelog][7].
-
-### Discussions, support, and help
-
-For general discussions, support, and help, please use many of the community
-spaces [listed on the sidebar of the Elixir website](https://elixir-lang.org/),
-such as forums, chat platforms, etc, where the wider community will be available
-to help you.
+[check Elixir's website](http://elixir-lang.org/).
 
 ## Compiling from source
 
-For the many different ways to install Elixir,
-[see our installation instructions on the website](https://elixir-lang.org/install.html).
-However, if you want to contribute to Elixir, you will need to compile from source.
-
-First, [install Erlang](https://elixir-lang.org/install.html#installing-erlang).
-After that, clone this repository to your machine, compile and test it:
+To run Elixir from source, clone this repository to your machine, compile and test it:
 
 ```sh
 git clone https://github.com/elixir-lang/elixir.git
@@ -88,34 +22,68 @@ make clean test
 [this article includes important notes for compiling Elixir from source
 on Windows](https://github.com/elixir-lang/elixir/wiki/Windows).
 
-In case you want to use this Elixir version as your system version,
-you need to add the `bin` directory to [your PATH environment variable](https://elixir-lang.org/install.html#setting-path-environment-variable).
-
 If Elixir fails to build (specifically when pulling in a new version via
 `git`), be sure to remove any previous build artifacts by running
 `make clean`, then `make test`.
 
+If tests pass, you are ready to move on to the [Getting Started guide][1]
+or to try Interactive Elixir by running `bin/iex` in your terminal.
+
+However, if tests fail, it is likely you have an outdated Erlang/OTP version
+(Elixir requires Erlang/OTP 19.0 or later). You can check your Erlang/OTP version
+by calling `erl` in the command line. You will see some information as follows:
+
+    Erlang/OTP 19 [erts-8.0] [smp:2:2] [async-threads:10] [kernel-poll:false]
+
+If you have properly set up your dependencies and tests still fail,
+you may want to open up a bug report, as explained next.
+
+## Bug reports
+
+For reporting bugs, [visit our issues tracker][2] and follow the steps
+for reporting a new issue. Please disclose security vulnerabilities
+privately at elixir-security@googlegroups.com.
+
+## Proposing new features
+
+For proposing new features, please start a discussion in the
+[Elixir Core mailing list][3]. Keep in mind that it is your responsibility
+to argue and explain why a feature is useful and how it will impact the
+codebase and the community.
+
+Once a proposal is accepted, it will be added to [the issues tracker][2].
+The issues tracker focuses on *actionable items* and it holds a list of
+upcoming enhancements and pending bugs. All entries in the tracker are
+tagged for clarity and to ease collaboration.
+
+Features and bug fixes that have already been merged and will be included
+in the next release are marked as "closed" in the issues tracker and are
+added to the [CHANGELOG](CHANGELOG.md).
+
+Finally, remember all interactions in our official spaces follow our
+[Code of Conduct][7].
+
 ## Contributing
 
 We welcome everyone to contribute to Elixir. To do so, there are a few
 things you need to know about the code. First, Elixir code is divided
 in applications inside the `lib` folder:
 
-* `elixir` - Elixir's kernel and standard library
+* `elixir` - Contains Elixir's kernel and stdlib
 
-* `eex` - EEx is the template engine that allows you to embed Elixir
+* `eex` - Template engine that allows you to embed Elixir
 
-* `ex_unit` - ExUnit is a simple test framework that ships with Elixir
+* `ex_unit` - Simple test framework that ships with Elixir
 
-* `iex` - IEx stands for Interactive Elixir: Elixir's interactive shell
+* `iex` - IEx, Elixir's interactive shell
 
-* `logger` - Logger is the built-in logger
+* `logger` - The built-in logger
 
-* `mix` - Mix is Elixir's build tool
+* `mix` - Elixir's build tool
 
 You can run all tests in the root directory with `make test` and you can
-also run tests for a specific framework `make test_#{APPLICATION}`, for example,
-`make test_ex_unit`. If you just changed something in Elixir's standard
+also run tests for a specific framework `make test_#{NAME}`, for example,
+`make test_ex_unit`. If you just changed something in the Elixir's standard
 library, you can run only that portion through `make test_stdlib`.
 
 If you are changing just one file, you can choose to compile and run tests only
@@ -127,21 +95,15 @@ bin/elixirc lib/elixir/lib/string.ex -o lib/elixir/ebin
 bin/elixir lib/elixir/test/elixir/string_test.exs
 ```
 
-You can also use the `LINE` env var to run a single test:
-
-```sh
-LINE=123 bin/elixir lib/elixir/test/elixir/string_test.exs
-````
-
 To recompile (including Erlang modules):
 
 ```sh
 make compile
 ```
 
-After your changes are done, please remember to run `make format` to guarantee
-all files are properly formatted and then run the full suite with
-`make test`.
+After your changes are done, please remember to run the full suite with
+`make test` and then `mix format` to guarantee all files are properly
+formatted.
 
 If your contribution fails during the bootstrapping of the language,
 you can rebuild the language from scratch with:
@@ -152,17 +114,17 @@ make clean_elixir compile
 
 Similarly, if you can't get Elixir to compile or the tests to pass after
 updating an existing checkout, run `make clean compile`. You can check
-[the official build status](https://github.com/elixir-lang/elixir/actions/workflows/ci.yml).
-More tasks can be found by reading the [Makefile](Makefile).
+[the official build status on Travis-CI](https://travis-ci.org/elixir-lang/elixir).
+More tasks can be found by reading the [Makefile](./Makefile).
 
 With tests running and passing, you are ready to contribute to Elixir and
 [send a pull request](https://help.github.com/articles/using-pull-requests/).
 We have saved some excellent pull requests we have received in the past in
 case you are looking for some examples:
 
-* [Implement Enum.member? - Pull request](https://github.com/elixir-lang/elixir/pull/992)
-* [Add String.valid? - Pull request](https://github.com/elixir-lang/elixir/pull/1058)
-* [Implement capture_io for ExUnit - Pull request](https://github.com/elixir-lang/elixir/pull/1059)
+* [Implement Enum.member? – Pull Request](https://github.com/elixir-lang/elixir/pull/992)
+* [Add String.valid? – Pull Request](https://github.com/elixir-lang/elixir/pull/1058)
+* [Implement capture_io for ExUnit – Pull Request](https://github.com/elixir-lang/elixir/pull/1059)
 
 ### Reviewing changes
 
@@ -171,12 +133,12 @@ We outline our process below to clarify the roles of everyone involved.
 
 All pull requests must be approved by two committers before being merged into
 the repository. If any changes are necessary, the team will leave appropriate
-comments requesting changes to the code. Unfortunately, we cannot guarantee a
+comments requesting changes to the code. Unfortunately we cannot guarantee a
 pull request will be merged, even when modifications are requested, as the Elixir
 team will re-evaluate the contribution as it changes.
 
 Committers may also push style changes directly to your branch. If you would
-rather manage all changes yourself, you can disable the "Allow edits from maintainers"
+rather manage all changes yourself, you can disable "Allow edits from maintainers"
 feature when submitting your pull request.
 
 The Elixir team may optionally assign someone to review a pull request.
@@ -185,8 +147,7 @@ another team member can merge it.
 
 When the review finishes, your pull request will be squashed and merged
 into the repository. If you have carefully organized your commits and
-believe they should be merged without squashing, please mention it in
-a comment.
+believe they should be merged without squashing, leave a comment.
 
 ## Building documentation
 
@@ -195,47 +156,37 @@ to be installed and built alongside Elixir:
 
 ```sh
 # After cloning and compiling Elixir, in its parent directory:
-git clone https://github.com/elixir-lang/ex_doc.git
-cd ex_doc && ../elixir/bin/mix do deps.get + compile
+git clone git://github.com/elixir-lang/ex_doc.git
+cd ex_doc && ../elixir/bin/mix do deps.get, compile
+cd ../elixir && make docs
 ```
 
-Now go back to Elixir's root directory and run:
-
-```sh
-make docs                  # to generate HTML pages
-make docs DOCS_FORMAT=epub # to generate EPUB documents
-```
-
-This will produce documentation sets for `elixir`, `eex`, `ex_unit`, `iex`, `logger`,
-and `mix` under the `doc` directory. If you are planning to contribute documentation,
+This will produce documentation sets for `elixir`, `mix`, etc. under
+the `doc` directory. If you are planning to contribute documentation,
 [please check our best practices for writing documentation](https://hexdocs.pm/elixir/writing-documentation.html).
 
 ## Development links
 
+  * [Elixir Getting Started guide][1]
   * [Elixir Documentation][6]
   * [Elixir Core Mailing list (development)][3]
-  * [Announcement mailing list][8]
-  * [Code of Conduct][1]
-  * [Issue tracker][2]
-  * [Changelog][7]
-  * [Security Policy][9]
-  * **[#elixir][4]** on [Libera.Chat][5] IRC
+  * [Issues tracker][2]
+  * [Code of Conduct][7]
+  * **[#elixir-lang][4]** on [Freenode][5] IRC
 
-  [1]: CODE_OF_CONDUCT.md
+  [1]: https://elixir-lang.org/getting-started/introduction.html
   [2]: https://github.com/elixir-lang/elixir/issues
   [3]: https://groups.google.com/group/elixir-lang-core
-  [4]: https://web.libera.chat/#elixir
-  [5]: https://libera.chat
-  [6]: https://elixir-lang.org/docs.html
-  [7]: CHANGELOG.md
-  [8]: https://groups.google.com/group/elixir-lang-ann
-  [9]: SECURITY.md
-  [10]: https://groups.google.com/forum/#!searchin/elixir-lang-ann/%5Bsecurity%5D%7Csort:date
+  [4]: https://webchat.freenode.net/?channels=#elixir-lang
+  [5]: http://www.freenode.net
+  [6]: http://elixir-lang.org/docs.html
+  [7]: CODE_OF_CONDUCT.md
 
 ## License
 
-"Elixir" and the Elixir logo are registered trademarks of The Elixir Team.
+"Elixir" and the Elixir logo are copyright (c) 2012 Plataformatec.
 
-Elixir source code is released under Apache License 2.0.
+Elixir source code is released under Apache 2 License.
 
-Check [NOTICE](NOTICE) and [LICENSE](LICENSE) files for more information.
+Check [NOTICE](NOTICE) and [LICENSE](LICENSE) files for more
+information.

RELEASE.md

@@ -4,19 +4,23 @@
 
 1. Ensure you are running on the oldest supported Erlang version
 
-2. Update version in /VERSION, bin/elixir and bin/elixir.bat
+2. Update version in /VERSION
 
 3. Ensure /CHANGELOG.md is updated, versioned and add the current date
 
 4. Update "Compatibility and Deprecations" if a new OTP version is supported
 
-5. Commit changes above with title "Release vVERSION", generate a new tag, and push it
+5. Commit changes above with title "Release vVERSION" and generate a new tag
 
-6. Wait until GitHub Actions publish artifacts to the draft release and the CI is green
+6. Run `make clean test` to ensure all tests pass from scratch and the CI is green
 
-7. Copy the relevant bits from /CHANGELOG.md to the GitHub release and publish it
+7. Recompile an existing project (for example, Ecto) to ensure manifests can be upgraded
 
-8. Add the release to `elixir.csv` with the minimum supported OTP version (all releases), update `erlang.csv` to the latest supported OTP version, and `_data/elixir-versions.yml` (except for RCs) files in `elixir-lang/elixir-lang.github.com`
+8. Push branch and the new tag
+
+9. Publish new zips with `make zips`, upload `Precompiled.zip` and `Docs.zip` to GitHub Releases, and include SHAs+CHANGELOG
+
+10. Add the release to `elixir.csv` and `_data/elixir-versions.yml` files in `elixir-lang/elixir-lang.github.com`
 
 ## Creating a new vMAJOR.MINOR branch
 
@@ -24,26 +28,14 @@
 
 1. Set `CANONICAL=` in /Makefile
 
-2. Update tables in /SECURITY.md and "Compatibility and Deprecations"
+2. Update **all** tables in "Compatibility and Deprecations"
 
-3. Commit "Branch out vMAJOR.MINOR"
+3. Commit "Prepare vMAJOR.MINOR for release"
 
-### Back in main
+### Back in master
 
-1. Bump /VERSION file, bin/elixir and bin/elixir.bat
+1. Bump /VERSION file
 
 2. Start new /CHANGELOG.md
 
-3. Update tables in /SECURITY.md and in "Compatibility and Deprecations"
-
-4. Commit "Start vMAJOR.MINOR+1"
-
-## Changing supported Erlang/OTP versions
-
-1. Update the table in Compatibility and Deprecations
-
-2. Update `otp_release` checks in /Makefile and `/lib/elixir/src/elixir.erl`
-
-3. Update CI workflows in `/.cirrus.yml`, `/.github/workflows/ci.yml`, and `/.github/workflows/releases.yml`
-
-4. Remove `otp_release` version checks that are no longer needed
+3. Commit "Start vMAJOR.MINOR+1"

SECURITY.md

@@ -1,23 +0,0 @@
-# Security Policy
-
-## Supported versions
-
-Elixir applies bug fixes only to the latest minor branch. Security patches are available for the last 5 minor branches:
-
-Elixir version | Support
-:------------- | :-----------------------------
-1.14           | Bug fixes and security patches
-1.13           | Security patches only
-1.12           | Security patches only
-1.11           | Security patches only
-1.10           | Security patches only
-
-## Announcements
-
-New releases are announced in the read-only [announcements mailing list](https://groups.google.com/group/elixir-lang-ann). You can subscribe by sending an email to elixir-lang-ann+subscribe@googlegroups.com and replying to the confirmation email.
-
-Security notifications [will be tagged with `[security]`](https://groups.google.com/forum/#!searchin/elixir-lang-ann/%5Bsecurity%5D%7Csort:date).
-
-## Reporting a vulnerability
-
-Please disclose security vulnerabilities privately at elixir-security@googlegroups.com

VERSION

@@ -1 +1 @@
-1.14.1
+1.7.3

bin/elixir

@@ -1,62 +1,31 @@
 #!/bin/sh
-set -e
+if [ $# -eq 0 ] || [ "$1" = "--help" ] || [ "$1" = "-h" ]; then
+  echo "Usage: `basename $0` [options] [.exs file] [data]
 
-ELIXIR_VERSION=1.14.1
+  -e COMMAND                  Evaluates the given command (*)
+  -r FILE                     Requires the given files/patterns (*)
+  -S SCRIPT                   Finds and executes the given script in PATH
+  -pr FILE                    Requires the given files/patterns in parallel (*)
+  -pa PATH                    Prepends the given path to Erlang code path (*)
+  -pz PATH                    Appends the given path to Erlang code path (*)
 
-if [ $# -eq 0 ] || { [ $# -eq 1 ] && { [ "$1" = "--help" ] || [ "$1" = "-h" ]; }; }; then
-  cat <<USAGE >&2
-Usage: $(basename "$0") [options] [.exs file] [data]
+  --app APP                   Starts the given app and its dependencies (*)
+  --cookie COOKIE             Sets a cookie for this distributed node
+  --detached                  Starts the Erlang VM detached from console
+  --erl SWITCHES              Switches to be passed down to Erlang (*)
+  --help, -h                  Prints this message and exits
+  --hidden                    Makes a hidden node
+  --logger-otp-reports BOOL   Enables or disables OTP reporting
+  --logger-sasl-reports BOOL  Enables or disables SASL reporting
+  --name NAME                 Makes and assigns a name to the distributed node
+  --no-halt                   Does not halt the Erlang VM after execution
+  --sname NAME                Makes and assigns a short name to the distributed node
+  --version, -v               Prints Elixir version and exits
+  --werl                      Uses Erlang's Windows shell GUI (Windows only)
 
-## General options
-
-  -e "COMMAND"                 Evaluates the given command (*)
-  -h, --help                   Prints this message (standalone)
-  -r "FILE"                    Requires the given files/patterns (*)
-  -S SCRIPT                    Finds and executes the given script in \$PATH
-  -pr "FILE"                   Requires the given files/patterns in parallel (*)
-  -pa "PATH"                   Prepends the given path to Erlang code path (*)
-  -pz "PATH"                   Appends the given path to Erlang code path (*)
-  -v, --version                Prints Erlang/OTP and Elixir versions (standalone)
-
-  --app APP                    Starts the given app and its dependencies (*)
-  --erl "SWITCHES"             Switches to be passed down to Erlang (*)
-  --eval "COMMAND"             Evaluates the given command, same as -e (*)
-  --logger-otp-reports BOOL    Enables or disables OTP reporting
-  --logger-sasl-reports BOOL   Enables or disables SASL reporting
-  --no-halt                    Does not halt the Erlang VM after execution
-  --short-version              Prints Elixir version (standalone)
-  --werl                       Uses Erlang's Windows shell GUI (Windows only)
-
-Options given after the .exs file or -- are passed down to the executed code.
-Options can be passed to the Erlang runtime using \$ELIXIR_ERL_OPTIONS or --erl.
-
-## Distribution options
-
-The following options are related to node distribution.
-
-  --cookie COOKIE              Sets a cookie for this distributed node
-  --hidden                     Makes a hidden node
-  --name NAME                  Makes and assigns a name to the distributed node
-  --rpc-eval NODE "COMMAND"    Evaluates the given command on the given remote node (*)
-  --sname NAME                 Makes and assigns a short name to the distributed node
-
-## Release options
-
-The following options are generally used under releases.
-
-  --boot "FILE"                Uses the given FILE.boot to start the system
-  --boot-var VAR "VALUE"       Makes \$VAR available as VALUE to FILE.boot (*)
-  --erl-config "FILE"          Loads configuration in FILE.config written in Erlang (*)
-  --pipe-to "PIPEDIR" "LOGDIR" Starts the Erlang VM as a named PIPEDIR and LOGDIR
-  --vm-args "FILE"             Passes the contents in file as arguments to the VM
-
---pipe-to starts Elixir detached from console (Unix-like only).
-It will attempt to create PIPEDIR and LOGDIR if they don't exist.
-See run_erl to learn more. To reattach, run: to_erl PIPEDIR.
-
-** Options marked with (*) can be given more than once.
-** Standalone options can't be combined with other options.
-USAGE
+** Options marked with (*) can be given more than once
+** Options given after the .exs file or -- are passed down to the executed code
+** Options can be passed to the Erlang runtime using ELIXIR_ERL_OPTIONS or --erl" >&2
   exit 1
 fi
 
@@ -66,152 +35,70 @@ readlink_f () {
   if [ -h "$filename" ]; then
     readlink_f "$(readlink "$filename")"
   else
-    echo "$(pwd -P)/$filename"
+    echo "`pwd -P`/$filename"
   fi
 }
 
-if [ $# -eq 1 ] && [ "$1" = "--short-version" ]; then
-  echo "$ELIXIR_VERSION"
-  exit 0
-fi
-
-# Stores static Erlang arguments and --erl (which is passed as is)
-ERL=""
-
-# Stores erl arguments preserving spaces/quotes (mimics an array)
-erl_set () {
-  eval "E${E}=\$1"
-  E=$((E + 1))
-}
-
-# Checks if a string starts with prefix. Usage: starts_with "$STRING" "$PREFIX"
-starts_with () {
-  case $1 in
-    "$2"*) true;;
-    *) false;;
-  esac
-}
-
-ERL_EXEC="erl"
 MODE="elixir"
+ERL_EXEC="erl"
+ERL=""
 I=1
-E=0
-LENGTH=$#
-set -- "$@" -extra
 
-while [ $I -le $LENGTH ]; do
-  # S counts to be shifted, C counts to be copied
-  S=0
-  C=0
-  case "$1" in
+while [ $I -le $# ]; do
+  S=1
+  eval "PEEK=\${$I}"
+  case "$PEEK" in
     +iex)
-        C=1
         MODE="iex"
         ;;
     +elixirc)
-        C=1
         MODE="elixirc"
         ;;
-    -v|--no-halt|--no-pry)
-        C=1
+    -v|--compile|--no-halt)
         ;;
-    -e|-r|-pr|-pa|-pz|--app|--eval|--remsh|--dot-iex)
-        C=2
+    -e|-r|-pr|-pa|-pz|--remsh|--app)
+        S=2
         ;;
-    --rpc-eval)
-        C=3
+    --detached|--hidden)
+        ERL="$ERL `echo $PEEK | cut -c 2-`"
         ;;
-    --hidden)
-        S=1
-        ERL="$ERL -hidden"
+    --cookie)
+        I=$(expr $I + 1)
+        eval "VAL=\${$I}"
+        ERL="$ERL -setcookie "$VAL""
+        ;;
+    --sname|--name)
+        I=$(expr $I + 1)
+        eval "VAL=\${$I}"
+        ERL="$ERL `echo $PEEK | cut -c 2-` "$VAL""
         ;;
     --logger-otp-reports)
-        S=2
-        if [ "$2" = 'true' ] || [ "$2" = 'false' ]; then
-          ERL="$ERL -logger handle_otp_reports $2"
+        I=$(expr $I + 1)
+        eval "VAL=\${$I}"
+        if [ "$VAL" = 'true' ] || [ "$VAL" = 'false' ]; then
+            ERL="$ERL -logger handle_otp_reports "$VAL""
         fi
         ;;
     --logger-sasl-reports)
-        S=2
-        if [ "$2" = 'true' ] || [ "$2" = 'false' ]; then
-          ERL="$ERL -logger handle_sasl_reports $2"
+        I=$(expr $I + 1)
+        eval "VAL=\${$I}"
+        if [ "$VAL" = 'true' ] || [ "$VAL" = 'false' ]; then
+            ERL="$ERL -logger handle_sasl_reports "$VAL""
         fi
         ;;
     --erl)
-        S=2
-        ERL="$ERL $2"
-        ;;
-    --cookie)
-        S=2
-        erl_set "-setcookie"
-        erl_set "$2"
-        ;;
-    --sname|--name)
-        S=2
-        erl_set "$(echo "$1" | cut -c 2-)"
-        erl_set "$2"
-        ;;
-    --erl-config)
-        S=2
-        erl_set "-config"
-        erl_set "$2"
-        ;;
-    --vm-args)
-        S=2
-        erl_set "-args_file"
-        erl_set "$2"
-        ;;
-    --boot)
-        S=2
-        erl_set "-boot"
-        erl_set "$2"
-        ;;
-    --boot-var)
-        S=3
-        erl_set "-boot_var"
-        erl_set "$2"
-        erl_set "$3"
-        ;;
-    --pipe-to)
-        S=3
-        RUN_ERL_PIPE="$2"
-        RUN_ERL_LOG="$3"
-        if [ "$(starts_with "$RUN_ERL_PIPE" "-")" ]; then
-          echo "--pipe-to : PIPEDIR cannot be a switch" >&2 && exit 1
-        elif [ "$(starts_with "$RUN_ERL_LOG" "-")" ]; then
-          echo "--pipe-to : LOGDIR cannot be a switch" >&2 && exit 1
-        fi
+        I=$(expr $I + 1)
+        eval "VAL=\${$I}"
+        ERL="$ERL "$VAL""
         ;;
     --werl)
-        S=1
-        if [ "$OS" = "Windows_NT" ]; then ERL_EXEC="werl"; fi
+        USE_WERL=true
         ;;
     *)
-        while [ $I -le $LENGTH ]; do
-          I=$((I + 1))
-          set -- "$@" "$1"
-          shift
-        done
         break
         ;;
   esac
-
-  while [ $I -le $LENGTH ] && [ $C -gt 0 ]; do
-    C=$((C - 1))
-    I=$((I + 1))
-    set -- "$@" "$1"
-    shift
-  done
-
-  I=$((I + S))
-  shift $S
-done
-
-I=$((E - 1))
-while [ $I -ge 0 ]; do
-  eval "VAL=\$E$I"
-  set -- "$VAL" "$@"
-  I=$((I - 1))
+  I=$(expr $I + $S)
 done
 
 SELF=$(readlink_f "$0")
@@ -220,30 +107,17 @@ SCRIPT_PATH=$(dirname "$SELF")
 if [ "$OSTYPE" = "cygwin" ]; then SCRIPT_PATH=$(cygpath -m "$SCRIPT_PATH"); fi
 if [ "$MODE" != "iex" ]; then ERL="-noshell -s elixir start_cli $ERL"; fi
 
-if [ "$OS" != "Windows_NT" ] && [ -z "$NO_COLOR" ]; then
+# Check for terminal support
+if [ "$OS" != "Windows_NT" ]; then
   if test -t 1 -a -t 2; then ERL="-elixir ansi_enabled true $ERL"; fi
 fi
 
-# One MAY change ERTS_BIN= but you MUST NOT change
-# ERTS_BIN=$ERTS_BIN as it is handled by Elixir releases.
-ERTS_BIN=
-ERTS_BIN="$ERTS_BIN"
-
-set -- "$ERTS_BIN$ERL_EXEC" -pa "$SCRIPT_PATH"/../lib/*/ebin $ELIXIR_ERL_OPTIONS $ERL "$@"
-
-if [ -n "$RUN_ERL_PIPE" ]; then
-  ESCAPED=""
-  for PART in "$@"; do
-    ESCAPED="$ESCAPED $(echo "$PART" | sed 's/[^a-zA-Z0-9_\-\/]/\\&/g')"
-  done
-  mkdir -p "$RUN_ERL_PIPE"
-  mkdir -p "$RUN_ERL_LOG"
-  ERL_EXEC="run_erl"
-  set -- "$ERTS_BIN$ERL_EXEC" -daemon "$RUN_ERL_PIPE/" "$RUN_ERL_LOG/" "$ESCAPED"
+if [ "$OS" = "Windows_NT" ] && [ $USE_WERL ]; then
+    ERL_EXEC="werl"
 fi
 
-if [ -n "$ELIXIR_CLI_DRY_RUN" ]; then
-  echo "$@"
-else
-  exec "$@"
+if [ -z "$ERL_PATH" ]; then
+  ERL_PATH="$ERL_EXEC"
 fi
+
+exec "$ERL_PATH" -pa "$SCRIPT_PATH"/../lib/*/ebin $ELIXIR_ERL_OPTIONS $ERL -extra "$@"

bin/elixir.bat

@@ -1,193 +1,114 @@
 @if defined ELIXIR_CLI_ECHO (@echo on) else (@echo off)
-
-set ELIXIR_VERSION=1.14.1
-
-setlocal enabledelayedexpansion
-if    ""%1""==""""                if ""%2""=="""" goto documentation
-if /I ""%1""==""--help""          if ""%2""=="""" goto documentation
-if /I ""%1""==""-h""              if ""%2""=="""" goto documentation
-if /I ""%1""==""/h""              if ""%2""=="""" goto documentation
-if    ""%1""==""/?""              if ""%2""=="""" goto documentation
-if /I ""%1""==""--short-version"" if ""%2""=="""" goto shortversion
+setlocal
+if    ""%1""==""""       goto documentation
+if /I ""%1""==""--help"" goto documentation
+if /I ""%1""==""-h""     goto documentation
+if /I ""%1""==""/h""     goto documentation
+if    ""%1""==""/?""     goto documentation
 goto parseopts
 
 :documentation
 echo Usage: %~nx0 [options] [.exs file] [data]
 echo.
-echo ## General options
+echo   -e COMMAND                  Evaluates the given command (*)
+echo   -r FILE                     Requires the given files/patterns (*)
+echo   -S SCRIPT                   Finds and executes the given script in PATH
+echo   -pr FILE                    Requires the given files/patterns in parallel (*)
+echo   -pa PATH                    Prepends the given path to Erlang code path (*)
+echo   -pz PATH                    Appends the given path to Erlang code path (*)
 echo.
-echo   -e "COMMAND"                 Evaluates the given command (*)
-echo   -h, --help                   Prints this message (standalone)
-echo   -r "FILE"                    Requires the given files/patterns (*)
-echo   -S SCRIPT                    Finds and executes the given script in $PATH
-echo   -pr "FILE"                   Requires the given files/patterns in parallel (*)
-echo   -pa "PATH"                   Prepends the given path to Erlang code path (*)
-echo   -pz "PATH"                   Appends the given path to Erlang code path (*)
-echo   -v, --version                Prints Erlang/OTP and Elixir versions (standalone)
+echo   --app APP                   Starts the given app and its dependencies (*)
+echo   --cookie COOKIE             Sets a cookie for this distributed node
+echo   --detached                  Starts the Erlang VM detached from console
+echo   --erl SWITCHES              Switches to be passed down to Erlang (*)
+echo   --help, -h                  Prints this message and exits
+echo   --hidden                    Makes a hidden node
+echo   --logger-otp-reports BOOL   Enables or disables OTP reporting
+echo   --logger-sasl-reports BOOL  Enables or disables SASL reporting
+echo   --name NAME                 Makes and assigns a name to the distributed node
+echo   --no-halt                   Does not halt the Erlang VM after execution
+echo   --sname NAME                Makes and assigns a short name to the distributed node
+echo   --version, -v               Prints Elixir version and exits
+echo   --werl                      Uses Erlang's Windows shell GUI
 echo.
-echo   --app APP                    Starts the given app and its dependencies (*)
-echo   --erl "SWITCHES"             Switches to be passed down to Erlang (*)
-echo   --eval "COMMAND"             Evaluates the given command, same as -e (*)
-echo   --logger-otp-reports BOOL    Enables or disables OTP reporting
-echo   --logger-sasl-reports BOOL   Enables or disables SASL reporting
-echo   --no-halt                    Does not halt the Erlang VM after execution
-echo   --short-version              Prints Elixir version (standalone)
-echo   --werl                       Uses Erlang's Windows shell GUI (Windows only)
-echo.
-echo Options given after the .exs file or -- are passed down to the executed code.
-echo Options can be passed to the Erlang runtime using $ELIXIR_ERL_OPTIONS or --erl.
-echo.
-echo ## Distribution options
-echo.
-echo The following options are related to node distribution.
-echo.
-echo   --cookie COOKIE              Sets a cookie for this distributed node
-echo   --hidden                     Makes a hidden node
-echo   --name NAME                  Makes and assigns a name to the distributed node
-echo   --rpc-eval NODE "COMMAND"    Evaluates the given command on the given remote node (*)
-echo   --sname NAME                 Makes and assigns a short name to the distributed node
-echo.
-echo ## Release options
-echo.
-echo The following options are generally used under releases.
-echo.
-echo   --boot "FILE"                Uses the given FILE.boot to start the system
-echo   --boot-var VAR "VALUE"       Makes $VAR available as VALUE to FILE.boot (*)
-echo   --erl-config "FILE"          Loads configuration in FILE.config written in Erlang (*)
-echo   --vm-args "FILE"             Passes the contents in file as arguments to the VM
-echo.
-echo --pipe-to is not supported on Windows. If set, Elixir won't boot.
-echo.
-echo ** Options marked with (*) can be given more than once.
-echo ** Standalone options can't be combined with other options.
-goto end
-
-:shortversion
-echo !ELIXIR_VERSION!
+echo ** Options marked with (*) can be given more than once
+echo ** Options given after the .exs file or -- are passed down to the executed code
+echo ** Options can be passed to the Erlang runtime using ELIXIR_ERL_OPTIONS or --erl
 goto end
 
 :parseopts
 
-rem Parameters for Elixir
-set parsElixir=
-
 rem Parameters for Erlang
 set parsErlang=
 
+rem Make sure we keep a copy of all parameters
+set allPars=%*
+
+rem Get the original path name from the batch file
+set originPath=%~dp0
+
 rem Optional parameters before the "-extra" parameter
 set beforeExtra=
 
-rem Option which determines whether the loop is over
-set endLoop=0
+rem Flag which determines whether or not to use werl vs erl
+set useWerl=0
 
 rem Designates which mode / Elixir component to run as
 set runMode="elixir"
 
-rem Designates the path to the current script
-set SCRIPT_PATH=%~dp0
-
-rem Designates the path to the ERTS system
-set ERTS_BIN=
-set ERTS_BIN=!ERTS_BIN!
-
 rem Recursive loop called for each parameter that parses the cmd line parameters
 :startloop
-set "par=%~1"
-if "!par!"=="" (
-  rem skip if no parameter
+set par="%1"
+shift
+if "%par%"=="" (
+  rem if no parameters defined
   goto expand_erl_libs
 )
-shift
-set par="!par:"=\"!"
-if !endLoop! == 1 (
-  set parsElixir=!parsElixir! !par!
-  goto startloop
+if "%par%"=="""" (
+  rem if no parameters defined - special case for parameter that is already quoted
+  goto expand_erl_libs
 )
 rem ******* EXECUTION OPTIONS **********************
-if !par!=="--werl"   (set useWerl=1 && goto startloop)
-if !par!=="+iex"     (set parsElixir=!parsElixir! +iex && set runMode="iex" && goto startloop)
-if !par!=="+elixirc" (set parsElixir=!parsElixir! +elixirc && set runMode="elixirc" && goto startloop)
-rem ******* EVAL PARAMETERS ************************
-if ""==!par:-e=! (
-  set "VAR=%~1"
-  if not defined VAR (set VAR= )
-  set parsElixir=!parsElixir! -e "!VAR:"=\"!"
-  shift
-  goto startloop
-)
-if ""==!par:--eval=! (
-  set "VAR=%~1"
-  if not defined VAR (set VAR= )
-  set parsElixir=!parsElixir! --eval "!VAR:"=\"!"
-  shift
-  goto startloop
-)
-if ""==!par:--rpc-eval=! (
-  set "VAR=%~2"
-  if not defined VAR (set VAR= )
-  set parsElixir=!parsElixir! --rpc-eval %1 "!VAR:"=\"!"
-  shift
-  shift
-  goto startloop
-)
+if "%par%"==""--werl"" (set useWerl=1)
+if "%par%"==""+iex"" (set runMode="iex")
 rem ******* ELIXIR PARAMETERS **********************
-if ""==!par:-r=!          (set "parsElixir=!parsElixir! -r %1" && shift && goto startloop)
-if ""==!par:-pr=!         (set "parsElixir=!parsElixir! -pr %1" && shift && goto startloop)
-if ""==!par:-pa=!         (set "parsElixir=!parsElixir! -pa %1" && shift && goto startloop)
-if ""==!par:-pz=!         (set "parsElixir=!parsElixir! -pz %1" && shift && goto startloop)
-if ""==!par:-v=!          (set "parsElixir=!parsElixir! -v" && goto startloop)
-if ""==!par:--version=!   (set "parsElixir=!parsElixir! --version" && goto startloop)
-if ""==!par:--app=!       (set "parsElixir=!parsElixir! --app %1" && shift && goto startloop)
-if ""==!par:--no-halt=!   (set "parsElixir=!parsElixir! --no-halt" && goto startloop)
-if ""==!par:--remsh=!     (set "parsElixir=!parsElixir! --remsh %1" && shift && goto startloop)
-if ""==!par:--dot-iex=!   (set "parsElixir=!parsElixir! --dot-iex %1" && shift && goto startloop)
-if ""==!par:--no-pry=!    (set "parsElixir=!parsElixir! --no-pry" && goto startloop)
+rem Note: we don't have to do anything with options that don't take an argument
+if """"=="%par:-e=%"      (shift)
+if """"=="%par:-r=%"      (shift)
+if """"=="%par:-pr=%"     (shift)
+if """"=="%par:-pa=%"     (shift)
+if """"=="%par:-pz=%"     (shift)
+if """"=="%par:--app=%"   (shift)
+if """"=="%par:--remsh=%" (shift)
 rem ******* ERLANG PARAMETERS **********************
-if ""==!par:--boot=!                (set "parsErlang=!parsErlang! -boot %1" && shift && goto startloop)
-if ""==!par:--boot-var=!            (set "parsErlang=!parsErlang! -boot_var %1 %2" && shift && shift && goto startloop)
-if ""==!par:--cookie=!              (set "parsErlang=!parsErlang! -setcookie %1" && shift && goto startloop)
-if ""==!par:--hidden=!              (set "parsErlang=!parsErlang! -hidden" && goto startloop)
-if ""==!par:--detached=!            (set "parsErlang=!parsErlang! -detached" && echo warning: the --detached option is deprecated && goto startloop)
-if ""==!par:--erl-config=!          (set "parsErlang=!parsErlang! -config %1" && shift && goto startloop)
-if ""==!par:--logger-otp-reports=!  (set "parsErlang=!parsErlang! -logger handle_otp_reports %1" && shift && goto startloop)
-if ""==!par:--logger-sasl-reports=! (set "parsErlang=!parsErlang! -logger handle_sasl_reports %1" && shift && goto startloop)
-if ""==!par:--name=!                (set "parsErlang=!parsErlang! -name %1" && shift && goto startloop)
-if ""==!par:--sname=!               (set "parsErlang=!parsErlang! -sname %1" && shift && goto startloop)
-if ""==!par:--vm-args=!             (set "parsErlang=!parsErlang! -args_file %1" && shift && goto startloop)
-if ""==!par:--erl=!                 (set "beforeExtra=!beforeExtra! %~1" && shift && goto startloop)
-if ""==!par:--pipe-to=!             (echo --pipe-to : Option is not supported on Windows && goto end)
-set endLoop=1
-set parsElixir=!parsElixir! !par!
-goto startloop
+if """"=="%par:--detached=%"            (set parsErlang=%parsErlang% -detached)
+if """"=="%par:--hidden=%"              (set parsErlang=%parsErlang% -hidden)
+if """"=="%par:--cookie=%"              (set parsErlang=%parsErlang% -setcookie %1 && shift)
+if """"=="%par:--sname=%"               (set parsErlang=%parsErlang% -sname %1 && shift)
+if """"=="%par:--name=%"                (set parsErlang=%parsErlang% -name %1 && shift)
+if """"=="%par:--logger-otp-reports=%"  (set parsErlang=%parsErlang% -logger handle_otp_reports %1 && shift)
+if """"=="%par:--logger-sasl-reports=%" (set parsErlang=%parsErlang% -logger handle_sasl_reports %1 && shift)
+if """"=="%par:--erl=%"                 (set "beforeExtra=%beforeExtra% %~1" && shift)
+goto:startloop
 
+rem ******* assume all pre-params are parsed ********************
 :expand_erl_libs
-rem expand all ebin paths as Windows does not support the ..\*\ebin wildcard
+rem ******* expand all ebin paths as Windows does not support the ..\*\ebin wildcard ********************
+setlocal enabledelayedexpansion
 set ext_libs=
-for  /d %%d in ("!SCRIPT_PATH!..\lib\*.") do (
+for  /d %%d in ("%originPath%..\lib\*.") do (
   set ext_libs=!ext_libs! -pa "%%~fd\ebin"
 )
+setlocal disabledelayedexpansion
 
 :run
-reg query HKCU\Console /v VirtualTerminalLevel 2>nul | findstr /e "0x1" >nul 2>nul
-if %errorlevel% == 0 (
-  set beforeExtra=-elixir ansi_enabled true !beforeExtra!
+if not %runMode% == "iex" (
+  set beforeExtra=-noshell -s elixir start_cli %beforeExtra%
 )
-if not !runMode! == "iex" (
-  set beforeExtra=-noshell -s elixir start_cli !beforeExtra!
-)
-if defined ELIXIR_CLI_DRY_RUN (
-   if defined useWerl (
-     echo start "" "!ERTS_BIN!werl.exe" !ext_libs! !ELIXIR_ERL_OPTIONS! !parsErlang! !beforeExtra! -extra !parsElixir!
-   ) else (
-     echo "!ERTS_BIN!erl.exe" !ext_libs! !ELIXIR_ERL_OPTIONS! !parsErlang! !beforeExtra! -extra !parsElixir!
-   )
+if %useWerl% equ 1 (
+  start werl.exe %ext_libs% %ELIXIR_ERL_OPTIONS% %parsErlang% %beforeExtra% -extra %*
 ) else (
-  if defined useWerl (
-    start "" "!ERTS_BIN!werl.exe" !ext_libs! !ELIXIR_ERL_OPTIONS! !parsErlang! !beforeExtra! -extra !parsElixir!
-  ) else (
-    "!ERTS_BIN!erl.exe" !ext_libs! !ELIXIR_ERL_OPTIONS! !parsErlang! !beforeExtra! -extra !parsElixir!
-  )
+  erl.exe %ext_libs% %ELIXIR_ERL_OPTIONS% %parsErlang% %beforeExtra% -extra %*
 )
-exit /B %ERRORLEVEL%
 :end
 endlocal

bin/elixirc

@@ -1,25 +1,20 @@
 #!/bin/sh
-set -e
-
 if [ $# -eq 0 ] || [ "$1" = "--help" ] || [ "$1" = "-h" ]; then
-  cat <<USAGE >&2
-Usage: $(basename "$0") [elixir switches] [compiler switches] [.ex files]
+  echo "Usage: `basename $0` [elixir switches] [compiler switches] [.ex files]
 
-  -h, --help                Prints this message and exits
   -o                        The directory to output compiled files
-  -v, --version             Prints Elixir version and exits (standalone)
 
+  --help, -h                Prints this message and exits
   --ignore-module-conflict  Does not emit warnings if a module was previously defined
   --no-debug-info           Does not attach debug info to compiled modules
   --no-docs                 Does not attach documentation to compiled modules
-  --profile time            Profile the time to compile modules
   --verbose                 Prints compilation status
-  --warnings-as-errors      Treats warnings as errors and return non-zero exit status
+  --version, -v             Prints Elixir version and exits
+  --warnings-as-errors      Treats warnings as errors and return non-zero exit code
 
-Options given after -- are passed down to the executed code.
-Options can be passed to the Erlang runtime using \$ELIXIR_ERL_OPTIONS.
-Options can be passed to the Erlang compiler using \$ERL_COMPILER_OPTIONS.
-USAGE
+** Options given after -- are passed down to the executed code
+** Options can be passed to the Erlang runtime using ELIXIR_ERL_OPTIONS
+** Options can be passed to the Erlang compiler using ERL_COMPILER_OPTIONS" >&2
   exit 1
 fi
 
@@ -29,7 +24,7 @@ readlink_f () {
   if [ -h "$filename" ]; then
     readlink_f "$(readlink "$filename")"
   else
-    echo "$(pwd -P)/$filename"
+    echo "`pwd -P`/$filename"
   fi
 }
 

bin/elixirc.bat

@@ -14,16 +14,15 @@ goto run
 :documentation
 echo Usage: %~nx0 [elixir switches] [compiler switches] [.ex files]
 echo.
-echo   -h, --help                Prints this message and exits
 echo   -o                        The directory to output compiled files
-echo   -v, --version             Prints Elixir version and exits (standalone)
 echo.
+echo   --help, -h                Prints this message and exits
 echo   --ignore-module-conflict  Does not emit warnings if a module was previously defined
 echo   --no-debug-info           Does not attach debug info to compiled modules
 echo   --no-docs                 Does not attach documentation to compiled modules
-echo   --profile time            Profile the time to compile modules
 echo   --verbose                 Prints compilation status
-echo   --warnings-as-errors      Treats warnings as errors and returns non-zero exit status
+echo   --version, -v             Prints Elixir version and exits
+echo   --warnings-as-errors      Treats warnings as errors and returns non-zero exit code
 echo.
 echo ** Options given after -- are passed down to the executed code
 echo ** Options can be passed to the Erlang runtime using ELIXIR_ERL_OPTIONS

bin/iex

@@ -1,20 +1,35 @@
 #!/bin/sh
-set -e
+if [ $# -gt 0 ] && ([ "$1" = "--help" ] || [ "$1" = "-h" ]); then
+  echo "Usage: `basename $0` [options] [.exs file] [data]
 
-if [ "$1" = "--help" ] || [ "$1" = "-h" ]; then
-  cat <<USAGE >&2
-Usage: $(basename "$0") [options] [.exs file] [data]
+  -e COMMAND                  Evaluates the given command (*)
+  -r FILE                     Requires the given files/patterns (*)
+  -S SCRIPT                   Finds and executes the given script in PATH
+  -pr FILE                    Requires the given files/patterns in parallel (*)
+  -pa PATH                    Prepends the given path to Erlang code path (*)
+  -pz PATH                    Appends the given path to Erlang code path (*)
 
-The following options are exclusive to IEx:
+  --app APP                   Starts the given app and its dependencies (*)
+  --cookie COOKIE             Sets a cookie for this distributed node
+  --detached                  Starts the Erlang VM detached from console
+  --erl SWITCHES              Switches to be passed down to Erlang (*)
+  --help, -h                  Prints this message and exits
+  --hidden                    Makes a hidden node
+  --logger-otp-reports BOOL   Enables or disables OTP reporting
+  --logger-sasl-reports BOOL  Enables or disables SASL reporting
+  --name NAME                 Makes and assigns a name to the distributed node
+  --no-halt                   Does not halt the Erlang VM after execution
+  --sname NAME                Makes and assigns a short name to the distributed node
+  --version, -v               Prints IEx version and exits
+  --werl                      Uses Erlang's Windows shell GUI (Windows only)
 
-  --dot-iex "FILE"    Evaluates FILE, line by line, to set up IEx' environment.
-                      Defaults to evaluating .iex.exs or ~/.iex.exs, if any exists.
-                      If FILE is empty, then no file will be loaded.
-  --remsh NAME        Connects to a node using a remote shell.
-  --no-pry            Doesn't start pry sessions when dbg/2 is called.
+  --dot-iex PATH              Overrides default .iex.exs file and uses path instead;
+                              path can be empty, then no file will be loaded
+  --remsh NAME                Connects to a node using a remote shell
 
-It accepts all other options listed by "elixir --help".
-USAGE
+** Options marked with (*) can be given more than once
+** Options given after the .exs file or -- are passed down to the executed code
+** Options can be passed to the VM using ELIXIR_ERL_OPTIONS or --erl" >&2
   exit 1
 fi
 
@@ -24,7 +39,7 @@ readlink_f () {
   if [ -h "$filename" ]; then
     readlink_f "$(readlink "$filename")"
   else
-    echo "$(pwd -P)/$filename"
+    echo "`pwd -P`/$filename"
   fi
 }
 

bin/iex.bat

@@ -1,4 +1,4 @@
-@if defined ELIXIR_CLI_ECHO (@echo on) else (@echo off)
+@if defined ELIXIR_CLI_ECHO (@echo on) else  (@echo off)
 setlocal
 if /I ""%1""==""--help"" goto documentation
 if /I ""%1""==""-h""     goto documentation
@@ -9,21 +9,38 @@ goto run
 :documentation
 echo Usage: %~nx0 [options] [.exs file] [data]
 echo.
-echo The following options are exclusive to IEx:
+echo   -e COMMAND                  Evaluates the given command (*)
+echo   -r FILE                     Requires the given files/patterns (*)
+echo   -S SCRIPT                   Finds and executes the given script in PATH
+echo   -pr FILE                    Requires the given files/patterns in parallel (*)
+echo   -pa PATH                    Prepends the given path to Erlang code path (*)
+echo   -pz PATH                    Appends the given path to Erlang code path (*)
 echo.
-echo   --dot-iex "FILE"    Evaluates FILE, line by line, to set up IEx' environment.
-echo                       Defaults to evaluating .iex.exs or ~/.iex.exs, if any exists.
-echo                       If FILE is empty, then no file will be loaded.
-echo   --remsh NAME        Connects to a node using a remote shell
-echo   --werl              Uses Erlang's Windows shell GUI (Windows only)
-echo   --no-pry            Doesn't start pry sessions when dbg/2 is called.
+echo   --app APP                   Starts the given app and its dependencies (*)
+echo   --cookie COOKIE             Sets a cookie for this distributed node
+echo   --detached                  Starts the Erlang VM detached from console
+echo   --erl SWITCHES              Switches to be passed down to Erlang (*)
+echo   --help, -h                  Prints this message and exits
+echo   --hidden                    Makes a hidden node
+echo   --logger-otp-reports BOOL   Enables or disables OTP reporting
+echo   --logger-sasl-reports BOOL  Enables or disables SASL reporting
+echo   --name NAME                 Makes and assigns a name to the distributed node
+echo   --no-halt                   Does not halt the Erlang VM after execution
+echo   --sname NAME                Makes and assigns a short name to the distributed node
+echo   --version, -v               Prints IEx version and exits
+echo   --werl                      Uses Erlang's Windows shell GUI (Windows only)
 echo.
-echo Set the IEX_WITH_WERL environment variable to always use werl.
-echo It accepts all other options listed by "elixir --help".
+echo   --dot-iex PATH              Overrides default .iex.exs file and uses path instead;
+echo                               path can be empty, then no file will be loaded
+echo   --remsh NAME                Connects to a node using a remote shell
+echo.
+echo ** Options marked with (*) can be given more than once
+echo ** Options given after the .exs file or -- are passed down to the executed code
+echo ** Options can be passed to the Erlang VM using ELIXIR_ERL_OPTIONS or --erl
 goto end
 
 :run
-if defined IEX_WITH_WERL (set __ELIXIR_IEX_FLAGS=--werl) else (set __ELIXIR_IEX_FLAGS=)
+@if defined IEX_WITH_WERL (@set __ELIXIR_IEX_FLAGS=--werl) else (set __ELIXIR_IEX_FLAGS=)
 call "%~dp0\elixir.bat" --no-halt --erl "-noshell -user Elixir.IEx.CLI" +iex %__ELIXIR_IEX_FLAGS% %*
 :end
 endlocal

bin/mix

@@ -1,3 +1,3 @@
 #!/usr/bin/env elixir
-Mix.start()
-Mix.CLI.main()
+Mix.start
+Mix.CLI.main

lib/eex/lib/eex.ex

@@ -1,81 +1,49 @@
 defmodule EEx.SyntaxError do
-  defexception [:message, :file, :line, :column]
+  defexception [:message, :file, :line]
 
   @impl true
   def message(exception) do
-    "#{exception.file}:#{exception.line}:#{exception.column}: #{exception.message}"
+    "#{exception.file}:#{exception.line}: #{exception.message}"
   end
 end
 
 defmodule EEx do
   @moduledoc ~S"""
-  EEx stands for Embedded Elixir.
-
-  Embedded Elixir allows you to embed Elixir code inside a string
-  in a robust way.
+  EEx stands for Embedded Elixir. It allows you to embed
+  Elixir code inside a string in a robust way.
 
       iex> EEx.eval_string("foo <%= bar %>", bar: "baz")
       "foo baz"
 
-  This module provides three main APIs for you to use:
+  ## API
 
-    1. Evaluate a string (`eval_string/3`) or a file (`eval_file/3`)
+  This module provides 3 main APIs for you to use:
+
+    1. Evaluate a string (`eval_string`) or a file (`eval_file`)
        directly. This is the simplest API to use but also the
-       slowest, since the code is evaluated at runtime and not precompiled.
+       slowest, since the code is evaluated and not compiled before.
 
-    2. Define a function from a string (`function_from_string/5`)
-       or a file (`function_from_file/5`). This allows you to embed
+    2. Define a function from a string (`function_from_string`)
+       or a file (`function_from_file`). This allows you to embed
        the template as a function inside a module which will then
        be compiled. This is the preferred API if you have access
        to the template at compilation time.
 
-    3. Compile a string (`compile_string/2`) or a file (`compile_file/2`)
+    3. Compile a string (`compile_string`) or a file (`compile_file`)
        into Elixir syntax tree. This is the API used by both functions
        above and is available to you if you want to provide your own
        ways of handling the compiled template.
 
-  The APIs above support several options, documented below. You may
-  also pass an engine which customizes how the EEx code is compiled.
-
   ## Options
 
-  All functions in this module, unless otherwise noted, accept EEx-related
-  options. They are:
+  All functions in this module accept EEx-related options.
+  They are:
 
+    * `:line` - the line to be used as the template start. Defaults to 1.
     * `:file` - the file to be used in the template. Defaults to the given
-      file the template is read from or to `"nofile"` when compiling from a string.
-
-    * `:line` - the line to be used as the template start. Defaults to `1`.
-
-    * `:indentation` - (since v1.11.0) an integer added to the column after every
-      new line. Defaults to `0`.
-
+      file the template is read from or to "nofile" when compiling from a string.
     * `:engine` - the EEx engine to be used for compilation.
-
-    * `:trim` - if `true`, trims whitespace left and right of quotation as
-      long as at least one newline is present. All subsequent newlines and
-      spaces are removed but one newline is retained. Defaults to `false`.
-
-    * `:parser_options` - (since: 1.13.0) allow customizing the parsed code
-      that is generated. See `Code.string_to_quoted/2` for available options.
-      Note that the options `:file`, `:line` and `:column` are ignored if
-      passed in. Defaults to `Code.get_compiler_option(:parser_options)`
-      (which defaults to `[]` if not set).
-
-  ## Tags
-
-  EEx supports multiple tags, declared below:
-
-      <% Elixir expression: executes code but discards output %>
-      <%= Elixir expression: executes code and prints result %>
-      <%% EEx quotation: returns the contents inside the tag as is %>
-      <%!-- Comments: they are discarded from source --%>
-
-  EEx supports additional tags, that may be used by some engines,
-  but they do not have a meaning by default:
-
-      <%| ... %>
-      <%/ ... %>
+    * `:trim` - trims whitespace left/right of quotation tags
 
   ## Engine
 
@@ -85,10 +53,36 @@ defmodule EEx do
   By default, `EEx` uses the `EEx.SmartEngine` that provides some
   conveniences on top of the simple `EEx.Engine`.
 
-  ### `EEx.SmartEngine`
+  ### Tags
 
-  The smart engine uses EEx default rules and adds the `@` construct
-  for reading template assigns:
+  `EEx.SmartEngine` supports the following tags:
+
+      <% Elixir expression - inline with output %>
+      <%= Elixir expression - replace with result %>
+      <%% EEx quotation - returns the contents inside %>
+      <%# Comments - they are discarded from source %>
+
+  All expressions that output something to the template
+  **must** use the equals sign (`=`). Since everything in
+  Elixir is an expression, there are no exceptions for this rule.
+  For example, while some template languages would special-case
+  `if/2` clauses, they are treated the same in EEx and
+  also require `=` in order to have their result printed:
+
+      <%= if true do %>
+        It is obviously true
+      <% else %>
+        This will never appear
+      <% end %>
+
+  Notice that different engines may have different rules
+  for each tag. Other tags may be added in future versions.
+
+  ### Macros
+
+  `EEx.SmartEngine` also adds some macros to your template.
+  An example is the `@` macro which allows easy data access
+  in a template:
 
       iex> EEx.eval_string("<%= @foo %>", assigns: [foo: 1])
       "1"
@@ -101,42 +95,27 @@ defmodule EEx do
   required by the template is not specified at compilation time.
   """
 
-  @type line :: non_neg_integer
-  @type column :: non_neg_integer
-  @type marker :: '=' | '/' | '|' | ''
-  @type metadata :: %{column: column, line: line}
-  @type token ::
-          {:comment, charlist, metadata}
-          | {:text, charlist, metadata}
-          | {:expr | :start_expr | :middle_expr | :end_expr, marker, charlist, metadata}
-          | {:eof, metadata}
-
   @doc """
-  Generates a function definition from the given string.
+  Generates a function definition from the string.
 
-  The first argument is the kind of the generated function (`:def` or `:defp`).
-  The `name` argument is the name that the generated function will have.
-  `template` is the string containing the EEx template. `args` is a list of arguments
-  that the generated function will accept. They will be available inside the EEx
-  template.
-
-  The supported `options` are described [in the module docs](#module-options).
+  The kind (`:def` or `:defp`) must be given, the
+  function name, its arguments and the compilation options.
 
   ## Examples
 
       iex> defmodule Sample do
       ...>   require EEx
-      ...>   EEx.function_from_string(:def, :sample, "<%= a + b %>", [:a, :b])
+      ...>   EEx.function_from_string :def, :sample, "<%= a + b %>", [:a, :b]
       ...> end
       iex> Sample.sample(1, 2)
       "3"
 
   """
-  defmacro function_from_string(kind, name, template, args \\ [], options \\ []) do
+  defmacro function_from_string(kind, name, source, args \\ [], options \\ []) do
     quote bind_quoted: binding() do
       info = Keyword.merge([file: __ENV__.file, line: __ENV__.line], options)
       args = Enum.map(args, fn arg -> {arg, [line: info[:line]], nil} end)
-      compiled = EEx.compile_string(template, info)
+      compiled = EEx.compile_string(source, info)
 
       case kind do
         :def -> def unquote(name)(unquote_splicing(args)), do: unquote(compiled)
@@ -148,17 +127,12 @@ defmodule EEx do
   @doc """
   Generates a function definition from the file contents.
 
-  The first argument is the kind of the generated function (`:def` or `:defp`).
-  The `name` argument is the name that the generated function will have.
-  `file` is the path to the EEx template file. `args` is a list of arguments
-  that the generated function will accept. They will be available inside the EEx
-  template.
+  The kind (`:def` or `:defp`) must be given, the
+  function name, its arguments and the compilation options.
 
   This function is useful in case you have templates but
   you want to precompile inside a module for speed.
 
-  The supported `options` are described [in the module docs](#module-options).
-
   ## Examples
 
       # sample.eex
@@ -167,17 +141,16 @@ defmodule EEx do
       # sample.ex
       defmodule Sample do
         require EEx
-        EEx.function_from_file(:def, :sample, "sample.eex", [:a, :b])
+        EEx.function_from_file :def, :sample, "sample.eex", [:a, :b]
       end
 
       # iex
-      Sample.sample(1, 2)
-      #=> "3"
+      Sample.sample(1, 2) #=> "3"
 
   """
   defmacro function_from_file(kind, name, file, args \\ [], options \\ []) do
     quote bind_quoted: binding() do
-      info = Keyword.merge([file: IO.chardata_to_string(file), line: 1], options)
+      info = Keyword.merge(options, file: file, line: 1)
       args = Enum.map(args, fn arg -> {arg, [line: 1], nil} end)
       compiled = EEx.compile_file(file, info)
 
@@ -191,86 +164,34 @@ defmodule EEx do
   end
 
   @doc """
-  Gets a string `source` and generates a quoted expression
+  Gets a string `source` and generate a quoted expression
   that can be evaluated by Elixir or compiled to a function.
-
-  This is useful if you want to compile a EEx template into code and inject
-  that code somewhere or evaluate it at runtime.
-
-  The generated quoted code will use variables defined in the template that
-  will be taken from the context where the code is evaluated. If you
-  have a template such as `<%= a + b %>`, then the returned quoted code
-  will use the `a` and `b` variables in the context where it's evaluated. See
-  examples below.
-
-  The supported `options` are described [in the module docs](#module-options).
-
-  ## Examples
-
-      iex> quoted = EEx.compile_string("<%= a + b %>")
-      iex> {result, _bindings} = Code.eval_quoted(quoted, a: 1, b: 2)
-      iex> result
-      "3"
-
   """
-  @spec compile_string(String.t(), keyword) :: Macro.t()
+  @spec compile_string(String.t(), keyword) :: Macro.t() | no_return
   def compile_string(source, options \\ []) when is_binary(source) and is_list(options) do
-    case tokenize(source, options) do
-      {:ok, tokens} ->
-        EEx.Compiler.compile(tokens, options)
-
-      {:error, message, %{column: column, line: line}} ->
-        file = options[:file] || "nofile"
-        raise EEx.SyntaxError, file: file, line: line, column: column, message: message
-    end
+    EEx.Compiler.compile(source, options)
   end
 
   @doc """
-  Gets a `filename` and generates a quoted expression
+  Gets a `filename` and generate a quoted expression
   that can be evaluated by Elixir or compiled to a function.
-
-  This is useful if you want to compile a EEx template into code and inject
-  that code somewhere or evaluate it at runtime.
-
-  The generated quoted code will use variables defined in the template that
-  will be taken from the context where the code is evaluated. If you
-  have a template such as `<%= a + b %>`, then the returned quoted code
-  will use the `a` and `b` variables in the context where it's evaluated. See
-  examples below.
-
-  The supported `options` are described [in the module docs](#module-options).
-
-  ## Examples
-
-      # sample.eex
-      <%= a + b %>
-
-      # In code:
-      quoted = EEx.compile_file("sample.eex")
-      {result, _bindings} = Code.eval_quoted(quoted, a: 1, b: 2)
-      result
-      #=> "3"
-
   """
-  @spec compile_file(Path.t(), keyword) :: Macro.t()
-  def compile_file(filename, options \\ []) when is_list(options) do
-    filename = IO.chardata_to_string(filename)
-    options = Keyword.merge([file: filename, line: 1], options)
+  @spec compile_file(String.t(), keyword) :: Macro.t() | no_return
+  def compile_file(filename, options \\ []) when is_binary(filename) and is_list(options) do
+    options = Keyword.merge(options, file: filename, line: 1)
     compile_string(File.read!(filename), options)
   end
 
   @doc """
   Gets a string `source` and evaluate the values using the `bindings`.
 
-  The supported `options` are described [in the module docs](#module-options).
-
   ## Examples
 
       iex> EEx.eval_string("foo <%= bar %>", bar: "baz")
       "foo baz"
 
   """
-  @spec eval_string(String.t(), keyword, keyword) :: String.t()
+  @spec eval_string(String.t(), keyword, keyword) :: any
   def eval_string(source, bindings \\ [], options \\ [])
       when is_binary(source) and is_list(bindings) and is_list(options) do
     compiled = compile_string(source, options)
@@ -280,64 +201,23 @@ defmodule EEx do
   @doc """
   Gets a `filename` and evaluate the values using the `bindings`.
 
-  The supported `options` are described [in the module docs](#module-options).
-
   ## Examples
 
       # sample.eex
       foo <%= bar %>
 
-      # IEx
-      EEx.eval_file("sample.eex", bar: "baz")
-      #=> "foo baz"
+      # iex
+      EEx.eval_file "sample.eex", [bar: "baz"] #=> "foo baz"
 
   """
-  @spec eval_file(Path.t(), keyword, keyword) :: String.t()
+  @spec eval_file(String.t(), keyword, keyword) :: any
   def eval_file(filename, bindings \\ [], options \\ [])
-      when is_list(bindings) and is_list(options) do
-    filename = IO.chardata_to_string(filename)
-    options = Keyword.put_new(options, :file, filename)
+      when is_binary(filename) and is_list(bindings) and is_list(options) do
+    options = Keyword.put(options, :file, filename)
     compiled = compile_file(filename, options)
     do_eval(compiled, bindings, options)
   end
 
-  @doc """
-  Tokenize the given contents according to the given options.
-
-  ## Options
-
-    * `:line` - An integer to start as line. Default is 1.
-    * `:column` - An integer to start as column. Default is 1.
-    * `:indentation` - An integer that indicates the indentation. Default is 0.
-    * `:trim` - Tells the tokenizer to either trim the content or not. Default is false.
-    * `:file` - Can be either a file or a string "nofile".
-
-  ## Examples
-
-      iex> EEx.tokenize('foo', line: 1, column: 1)
-      {:ok, [{:text, 'foo', %{column: 1, line: 1}}, {:eof, %{column: 4, line: 1}}]}
-
-  ## Result
-
-  It returns `{:ok, [token]}` where a token is one of:
-
-    * `{:text, content, %{column: column, line: line}}`
-    * `{:expr, marker, content, %{column: column, line: line}}`
-    * `{:start_expr, marker, content, %{column: column, line: line}}`
-    * `{:middle_expr, marker, content, %{column: column, line: line}}`
-    * `{:end_expr, marker, content, %{column: column, line: line}}`
-    * `{:eof, %{column: column, line: line}}`
-
-  Or `{:error, message, %{column: column, line: line}}` in case of errors.
-  Note new tokens may be added in the future.
-  """
-  @doc since: "1.14.0"
-  @spec tokenize(IO.chardata(), opts :: keyword) ::
-          {:ok, [token()]} | {:error, String.t(), metadata()}
-  def tokenize(contents, opts \\ []) do
-    EEx.Compiler.tokenize(contents, opts)
-  end
-
   ### Helpers
 
   defp do_eval(compiled, bindings, options) do

lib/eex/lib/eex/compiler.ex

@@ -3,415 +3,128 @@ defmodule EEx.Compiler do
 
   # When changing this setting, don't forget to update the docs for EEx
   @default_engine EEx.SmartEngine
-  @h_spaces [?\s, ?\t]
-  @all_spaces [?\s, ?\t, ?\n, ?\r]
-
-  @doc """
-  Tokenize EEx contents.
-  """
-  def tokenize(contents, opts) when is_binary(contents) do
-    tokenize(String.to_charlist(contents), opts)
-  end
-
-  def tokenize(contents, opts) when is_list(contents) do
-    file = opts[:file] || "nofile"
-    line = opts[:line] || 1
-    trim = opts[:trim] || false
-    indentation = opts[:indentation] || 0
-    column = indentation + (opts[:column] || 1)
-
-    state = %{trim: trim, indentation: indentation, file: file}
-
-    {contents, line, column} =
-      (trim && trim_init(contents, line, column, state)) || {contents, line, column}
-
-    tokenize(contents, line, column, state, [{line, column}], [])
-  end
-
-  defp tokenize('<%%' ++ t, line, column, state, buffer, acc) do
-    tokenize(t, line, column + 3, state, [?%, ?< | buffer], acc)
-  end
-
-  defp tokenize('<%!--' ++ t, line, column, state, buffer, acc) do
-    case comment(t, line, column + 5, state, []) do
-      {:error, line, column, message} ->
-        {:error, message, %{line: line, column: column}}
-
-      {:ok, new_line, new_column, rest, comments} ->
-        token = {:comment, Enum.reverse(comments), %{line: line, column: column}}
-        trim_and_tokenize(rest, new_line, new_column, state, buffer, acc, &[token | &1])
-    end
-  end
-
-  # TODO: Deprecate this on Elixir v1.18
-  defp tokenize('<%#' ++ t, line, column, state, buffer, acc) do
-    case expr(t, line, column + 3, state, []) do
-      {:error, line, column, message} ->
-        {:error, message, %{line: line, column: column}}
-
-      {:ok, _, new_line, new_column, rest} ->
-        trim_and_tokenize(rest, new_line, new_column, state, buffer, acc, & &1)
-    end
-  end
-
-  defp tokenize('<%' ++ t, line, column, state, buffer, acc) do
-    {marker, t} = retrieve_marker(t)
-
-    case expr(t, line, column + 2 + length(marker), state, []) do
-      {:error, line, column, message} ->
-        {:error, message, %{line: line, column: column}}
-
-      {:ok, expr, new_line, new_column, rest} ->
-        {key, expr} =
-          case :elixir_tokenizer.tokenize(expr, 1, file: "eex", check_terminators: false) do
-            {:ok, _line, _column, warnings, tokens} ->
-              Enum.each(Enum.reverse(warnings), fn {location, file, msg} ->
-                :elixir_errors.erl_warn(location, file, msg)
-              end)
-
-              token_key(tokens, expr)
-
-            {:error, _, _, _, _} ->
-              {:expr, expr}
-          end
-
-        marker =
-          if key in [:middle_expr, :end_expr] and marker != '' do
-            message =
-              "unexpected beginning of EEx tag \"<%#{marker}\" on \"<%#{marker}#{expr}%>\", " <>
-                "please remove \"#{marker}\""
-
-            :elixir_errors.erl_warn({line, column}, state.file, message)
-            ''
-          else
-            marker
-          end
-
-        token = {key, marker, expr, %{line: line, column: column}}
-        trim_and_tokenize(rest, new_line, new_column, state, buffer, acc, &[token | &1])
-    end
-  end
-
-  defp tokenize('\n' ++ t, line, _column, state, buffer, acc) do
-    tokenize(t, line + 1, state.indentation + 1, state, [?\n | buffer], acc)
-  end
-
-  defp tokenize([h | t], line, column, state, buffer, acc) do
-    tokenize(t, line, column + 1, state, [h | buffer], acc)
-  end
-
-  defp tokenize([], line, column, _state, buffer, acc) do
-    eof = {:eof, %{line: line, column: column}}
-    {:ok, Enum.reverse([eof | tokenize_text(buffer, acc)])}
-  end
-
-  defp trim_and_tokenize(rest, line, column, state, buffer, acc, fun) do
-    {rest, line, column, buffer} = trim_if_needed(rest, line, column, state, buffer)
-
-    acc = tokenize_text(buffer, acc)
-    tokenize(rest, line, column, state, [{line, column}], fun.(acc))
-  end
-
-  # Retrieve marker for <%
-
-  defp retrieve_marker([marker | t]) when marker in [?=, ?/, ?|] do
-    {[marker], t}
-  end
-
-  defp retrieve_marker(t) do
-    {'', t}
-  end
-
-  # Tokenize a multi-line comment until we find --%>
-
-  defp comment([?-, ?-, ?%, ?> | t], line, column, _state, buffer) do
-    {:ok, line, column + 4, t, buffer}
-  end
-
-  defp comment('\n' ++ t, line, _column, state, buffer) do
-    comment(t, line + 1, state.indentation + 1, state, '\n' ++ buffer)
-  end
-
-  defp comment([head | t], line, column, state, buffer) do
-    comment(t, line, column + 1, state, [head | buffer])
-  end
-
-  defp comment([], line, column, _state, _buffer) do
-    {:error, line, column, "missing token '--%>'"}
-  end
-
-  # Tokenize an expression until we find %>
-
-  defp expr([?%, ?> | t], line, column, _state, buffer) do
-    {:ok, Enum.reverse(buffer), line, column + 2, t}
-  end
-
-  defp expr('\n' ++ t, line, _column, state, buffer) do
-    expr(t, line + 1, state.indentation + 1, state, [?\n | buffer])
-  end
-
-  defp expr([h | t], line, column, state, buffer) do
-    expr(t, line, column + 1, state, [h | buffer])
-  end
-
-  defp expr([], line, column, _state, _buffer) do
-    {:error, line, column, "missing token '%>'"}
-  end
-
-  # Receives tokens and check if it is a start, middle or an end token.
-  defp token_key(tokens, expr) do
-    case {tokens, tokens |> Enum.reverse() |> drop_eol()} do
-      {[{:end, _} | _], [{:do, _} | _]} ->
-        {:middle_expr, expr}
-
-      {_, [{:do, _} | _]} ->
-        {:start_expr, maybe_append_space(expr)}
-
-      {_, [{:block_identifier, _, _} | _]} ->
-        {:middle_expr, maybe_append_space(expr)}
-
-      {[{:end, _} | _], [{:stab_op, _, _} | _]} ->
-        {:middle_expr, expr}
-
-      {_, [{:stab_op, _, _} | reverse_tokens]} ->
-        fn_index = Enum.find_index(reverse_tokens, &match?({:fn, _}, &1)) || :infinity
-        end_index = Enum.find_index(reverse_tokens, &match?({:end, _}, &1)) || :infinity
-
-        if end_index > fn_index do
-          {:start_expr, expr}
-        else
-          {:middle_expr, expr}
-        end
-
-      {tokens, _} ->
-        case Enum.drop_while(tokens, &closing_bracket?/1) do
-          [{:end, _} | _] -> {:end_expr, expr}
-          _ -> {:expr, expr}
-        end
-    end
-  end
-
-  defp drop_eol([{:eol, _} | rest]), do: drop_eol(rest)
-  defp drop_eol(rest), do: rest
-
-  defp maybe_append_space([?\s]), do: [?\s]
-  defp maybe_append_space([h]), do: [h, ?\s]
-  defp maybe_append_space([h | t]), do: [h | maybe_append_space(t)]
-
-  defp closing_bracket?({closing, _}) when closing in ~w"( [ {"a, do: true
-  defp closing_bracket?(_), do: false
-
-  # Tokenize the buffered text by appending
-  # it to the given accumulator.
-
-  defp tokenize_text([{_line, _column}], acc) do
-    acc
-  end
-
-  defp tokenize_text(buffer, acc) do
-    [{line, column} | buffer] = Enum.reverse(buffer)
-    [{:text, buffer, %{line: line, column: column}} | acc]
-  end
-
-  ## Trim
-
-  defp trim_if_needed(rest, line, column, state, buffer) do
-    if state.trim do
-      buffer = trim_left(buffer, 0)
-      {rest, line, column} = trim_right(rest, line, column, 0, state)
-      {rest, line, column, buffer}
-    else
-      {rest, line, column, buffer}
-    end
-  end
-
-  defp trim_init([h | t], line, column, state) when h in @h_spaces,
-    do: trim_init(t, line, column + 1, state)
-
-  defp trim_init([?\r, ?\n | t], line, _column, state),
-    do: trim_init(t, line + 1, state.indentation + 1, state)
-
-  defp trim_init([?\n | t], line, _column, state),
-    do: trim_init(t, line + 1, state.indentation + 1, state)
-
-  defp trim_init([?<, ?% | _] = rest, line, column, _state),
-    do: {rest, line, column}
-
-  defp trim_init(_, _, _, _), do: false
-
-  defp trim_left(buffer, count) do
-    case trim_whitespace(buffer, 0) do
-      {[?\n, ?\r | rest], _} -> trim_left(rest, count + 1)
-      {[?\n | rest], _} -> trim_left(rest, count + 1)
-      _ when count > 0 -> [?\n | buffer]
-      _ -> buffer
-    end
-  end
-
-  defp trim_right(rest, line, column, last_column, state) do
-    case trim_whitespace(rest, column) do
-      {[?\r, ?\n | rest], column} ->
-        trim_right(rest, line + 1, state.indentation + 1, column + 1, state)
-
-      {[?\n | rest], column} ->
-        trim_right(rest, line + 1, state.indentation + 1, column, state)
-
-      {[], column} ->
-        {[], line, column}
-
-      _ when last_column > 0 ->
-        {[?\n | rest], line - 1, last_column}
-
-      _ ->
-        {rest, line, column}
-    end
-  end
-
-  defp trim_whitespace([h | t], column) when h in @h_spaces, do: trim_whitespace(t, column + 1)
-  defp trim_whitespace(list, column), do: {list, column}
 
   @doc """
   This is the compilation entry point. It glues the tokenizer
   and the engine together by handling the tokens and invoking
   the engine every time a full expression or text is received.
   """
-  @spec compile([EEx.token()], keyword) :: Macro.t()
-  def compile(tokens, opts) do
+  @spec compile(String.t(), keyword) :: Macro.t() | no_return
+  def compile(source, opts) when is_binary(source) and is_list(opts) do
     file = opts[:file] || "nofile"
     line = opts[:line] || 1
-    parser_options = opts[:parser_options] || Code.get_compiler_option(:parser_options)
-    engine = opts[:engine] || @default_engine
+    trim = opts[:trim] || false
 
-    state = %{
-      engine: engine,
-      file: file,
-      line: line,
-      quoted: [],
-      start_line: nil,
-      start_column: nil,
-      parser_options: parser_options
-    }
+    case EEx.Tokenizer.tokenize(source, line, trim: trim) do
+      {:ok, tokens} ->
+        state = %{
+          engine: opts[:engine] || @default_engine,
+          file: file,
+          line: line,
+          quoted: [],
+          start_line: nil
+        }
 
-    init = state.engine.init(opts)
-    generate_buffer(tokens, init, [], state)
-  end
+        init = state.engine.init(opts)
+        generate_buffer(tokens, init, [], state)
 
-  # Ignore tokens related to comment.
-  defp generate_buffer([{:comment, _chars, _meta} | rest], buffer, scope, state) do
-    generate_buffer(rest, buffer, scope, state)
+      {:error, line, message} ->
+        raise EEx.SyntaxError, line: line, file: file, message: message
+    end
   end
 
   # Generates the buffers by handling each expression from the tokenizer.
   # It returns Macro.t/0 or it raises.
 
-  defp generate_buffer([{:text, chars, meta} | rest], buffer, scope, state) do
-    buffer =
-      if function_exported?(state.engine, :handle_text, 3) do
-        meta = [line: meta.line, column: meta.column]
-        state.engine.handle_text(buffer, meta, IO.chardata_to_string(chars))
-      else
-        # TODO: Deprecate this branch on Elixir v1.18.
-        # We should most likely move this check to init to emit the deprecation once.
-        state.engine.handle_text(buffer, IO.chardata_to_string(chars))
-      end
-
+  defp generate_buffer([{:text, chars} | rest], buffer, scope, state) do
+    buffer = state.engine.handle_text(buffer, IO.chardata_to_string(chars))
     generate_buffer(rest, buffer, scope, state)
   end
 
-  defp generate_buffer([{:expr, mark, chars, meta} | rest], buffer, scope, state) do
-    options =
-      [file: state.file, line: meta.line, column: column(meta.column, mark)] ++
-        state.parser_options
-
-    expr = Code.string_to_quoted!(chars, options)
+  defp generate_buffer([{:expr, line, mark, chars} | rest], buffer, scope, state) do
+    expr = Code.string_to_quoted!(chars, line: line, file: state.file)
     buffer = state.engine.handle_expr(buffer, IO.chardata_to_string(mark), expr)
     generate_buffer(rest, buffer, scope, state)
   end
 
-  defp generate_buffer(
-         [{:start_expr, mark, chars, meta} | rest],
-         buffer,
-         scope,
-         state
-       ) do
-    if mark == '' do
-      message =
-        "the contents of this expression won't be output unless the EEx block starts with \"<%=\""
-
-      :elixir_errors.erl_warn({meta.line, meta.column}, state.file, message)
-    end
-
-    {rest, line, contents} = look_ahead_middle(rest, meta.line, chars) || {rest, meta.line, chars}
+  defp generate_buffer([{:start_expr, start_line, mark, chars} | rest], buffer, scope, state) do
+    {contents, line, rest} = look_ahead_text(rest, start_line, chars)
 
     {contents, rest} =
-      generate_buffer(
-        rest,
-        state.engine.handle_begin(buffer),
-        [contents | scope],
-        %{
-          state
-          | quoted: [],
-            line: line,
-            start_line: meta.line,
-            start_column: column(meta.column, mark)
-        }
-      )
+      generate_buffer(rest, state.engine.handle_begin(buffer), [contents | scope], %{
+        state
+        | quoted: [],
+          line: line,
+          start_line: start_line
+      })
 
     buffer = state.engine.handle_expr(buffer, IO.chardata_to_string(mark), contents)
     generate_buffer(rest, buffer, scope, state)
   end
 
-  defp generate_buffer(
-         [{:middle_expr, '', chars, meta} | rest],
-         buffer,
-         [current | scope],
-         state
-       ) do
-    {wrapped, state} = wrap_expr(current, meta.line, buffer, chars, state)
-    state = %{state | line: meta.line}
+  defp generate_buffer([{:middle_expr, line, '', chars} | rest], buffer, [current | scope], state) do
+    {wrapped, state} = wrap_expr(current, line, buffer, chars, state)
+    state = %{state | line: line}
     generate_buffer(rest, state.engine.handle_begin(buffer), [wrapped | scope], state)
   end
 
-  defp generate_buffer([{:middle_expr, _, chars, meta} | _], _buffer, [], state) do
+  defp generate_buffer(
+         [{:middle_expr, line, modifier, chars} | t],
+         buffer,
+         [_ | _] = scope,
+         state
+       ) do
+    message =
+      "unexpected beginning of EEx tag \"<%#{modifier}\" on \"<%#{modifier}#{chars}%>\", " <>
+        "please remove \"#{modifier}\" accordingly"
+
+    :elixir_errors.warn(line, state.file, message)
+    generate_buffer([{:middle_expr, line, '', chars} | t], buffer, scope, state)
+    # TODO: Make this an error on Elixir v2.0 since it accidentally worked previously.
+    # raise EEx.SyntaxError, message: message, file: state.file, line: line
+  end
+
+  defp generate_buffer([{:middle_expr, line, _, chars} | _], _buffer, [], state) do
     raise EEx.SyntaxError,
       message: "unexpected middle of expression <%#{chars}%>",
       file: state.file,
-      line: meta.line,
-      column: meta.column
+      line: line
   end
 
-  defp generate_buffer(
-         [{:end_expr, '', chars, meta} | rest],
-         buffer,
-         [current | _],
-         state
-       ) do
-    {wrapped, state} = wrap_expr(current, meta.line, buffer, chars, state)
-    column = state.start_column
-    options = [file: state.file, line: state.start_line, column: column] ++ state.parser_options
-    tuples = Code.string_to_quoted!(wrapped, options)
+  defp generate_buffer([{:end_expr, line, '', chars} | rest], buffer, [current | _], state) do
+    {wrapped, state} = wrap_expr(current, line, buffer, chars, state)
+    tuples = Code.string_to_quoted!(wrapped, line: state.start_line, file: state.file)
     buffer = insert_quoted(tuples, state.quoted)
     {buffer, rest}
   end
 
-  defp generate_buffer([{:end_expr, _, chars, meta} | _], _buffer, [], state) do
+  defp generate_buffer([{:end_expr, line, modifier, chars} | t], buffer, [_ | _] = scope, state) do
+    message =
+      "unexpected beginning of EEx tag \"<%#{modifier}\" on end of " <>
+        "expression \"<%#{modifier}#{chars}%>\", please remove \"#{modifier}\" accordingly"
+
+    :elixir_errors.warn(line, state.file, message)
+    generate_buffer([{:end_expr, line, '', chars} | t], buffer, scope, state)
+    # TODO: Make this an error on Elixir v2.0 since it accidentally worked previously.
+    # raise EEx.SyntaxError, message: message, file: state.file, line: line
+  end
+
+  defp generate_buffer([{:end_expr, line, _, chars} | _], _buffer, [], state) do
     raise EEx.SyntaxError,
       message: "unexpected end of expression <%#{chars}%>",
       file: state.file,
-      line: meta.line,
-      column: meta.column
+      line: line
   end
 
-  defp generate_buffer([{:eof, _meta}], buffer, [], state) do
+  defp generate_buffer([], buffer, [], state) do
     state.engine.handle_body(buffer)
   end
 
-  defp generate_buffer([{:eof, meta}], _buffer, _scope, state) do
+  defp generate_buffer([], _buffer, _scope, state) do
     raise EEx.SyntaxError,
       message: "unexpected end of string, expected a closing '<% end %>'",
       file: state.file,
-      line: meta.line,
-      column: meta.column
+      line: state.line
   end
 
   # Creates a placeholder and wrap it inside the expression block
@@ -426,29 +139,30 @@ defmodule EEx.Compiler do
     {count, new_state}
   end
 
-  # Look middle expressions that immediately follow a start_expr
+  # Look text ahead on expressions
 
-  defp look_ahead_middle([{:comment, _comment, _meta} | rest], start, contents),
-    do: look_ahead_middle(rest, start, contents)
-
-  defp look_ahead_middle([{:text, text, _meta} | rest], start, contents) do
+  defp look_ahead_text(
+         [{:text, text}, {:middle_expr, line, _, chars} | rest] = tokens,
+         start,
+         contents
+       ) do
     if only_spaces?(text) do
-      look_ahead_middle(rest, start, contents ++ text)
+      {contents ++ text ++ chars, line, rest}
     else
-      nil
+      {contents, start, tokens}
     end
   end
 
-  defp look_ahead_middle([{:middle_expr, _, chars, meta} | rest], _start, contents) do
-    {rest, meta.line, contents ++ chars}
+  defp look_ahead_text([{:middle_expr, line, _, chars} | rest], _start, contents) do
+    {contents ++ chars, line, rest}
   end
 
-  defp look_ahead_middle(_tokens, _start, _contents) do
-    nil
+  defp look_ahead_text(tokens, start, contents) do
+    {contents, start, tokens}
   end
 
   defp only_spaces?(chars) do
-    Enum.all?(chars, &(&1 in @all_spaces))
+    Enum.all?(chars, &(&1 in [?\s, ?\t, ?\r, ?\n]))
   end
 
   # Changes placeholder to real expression
@@ -473,9 +187,4 @@ defmodule EEx.Compiler do
   defp insert_quoted(other, _quoted) do
     other
   end
-
-  defp column(column, mark) do
-    # length('<%') == 2
-    column + 2 + length(mark)
-  end
 end

lib/eex/lib/eex/engine.ex

@@ -2,73 +2,61 @@ defmodule EEx.Engine do
   @moduledoc ~S"""
   Basic EEx engine that ships with Elixir.
 
-  An engine needs to implement all callbacks below.
+  An engine needs to implement six functions:
 
-  This module also ships with a default engine implementation
-  you can delegate to. See `EEx.SmartEngine` as an example.
+    * `init(opts)` - called at the beginning of every text
+      and it must return the initial state.
+
+    * `handle_body(state)` - receives the state of the document
+      and it must return a quoted expression.
+
+    * `handle_text(state, text)` - it receives the state,
+      the text and must return a new quoted expression.
+
+    * `handle_expr(state, marker, expr)` - it receives the state,
+      the marker, the expr and must return a new state.
+
+    * `handle_begin(state)` - called every time there a new state
+      is needed with an empty buffer. Typically called for do/end
+      blocks, case expressions, anonymous functions, etc
+
+    * `handle_end(state)` - opposite of `handle_begin(state)` and
+      it must return quoted expression
+
+      The marker is what follows exactly after `<%`. For example,
+      `<% foo %>` has an empty marker, but `<%= foo %>` has `"="`
+      as marker. The allowed markers so far are: 
+
+        * `""`
+        * `"="`
+        * `"/"`
+        * `"|"`
+
+      Markers `"/"` and `"|"` are only for use in custom EEx engines
+      and are not implemented by default. Using them without the
+      implementation raises `EEx.SyntaxError`.
+
+      If your engine does not implement all markers, please ensure that
+      `handle_expr/3` falls back to `EEx.Engine.handle_expr/3` 
+      to raise the proper error message.
+
+      Read `handle_expr/3` below for more information about the markers
+      implemented by default by this engine.
+
+  `EEx.Engine` can be used directly if one desires to use the
+  default implementations for the functions above.
   """
 
   @type state :: term
 
-  @doc """
-  Called at the beginning of every template.
-
-  It must return the initial state.
-  """
   @callback init(opts :: keyword) :: state
-
-  @doc """
-  Called at the end of every template.
-
-  It must return Elixir's quoted expressions for the template.
-  """
   @callback handle_body(state) :: Macro.t()
-
-  @doc """
-  Called for the text/static parts of a template.
-
-  It must return the updated state.
-  """
-  @callback handle_text(state, [line: pos_integer, column: pos_integer], text :: String.t()) ::
-              state
-
-  @doc """
-  Called for the dynamic/code parts of a template.
-
-  The marker is what follows exactly after `<%`. For example,
-  `<% foo %>` has an empty marker, but `<%= foo %>` has `"="`
-  as marker. The allowed markers so far are:
-
-    * `""`
-    * `"="`
-    * `"/"`
-    * `"|"`
-
-  Markers `"/"` and `"|"` are only for use in custom EEx engines
-  and are not implemented by default. Using them without an
-  appropriate implementation raises `EEx.SyntaxError`.
-
-  It must return the updated state.
-  """
+  @callback handle_text(state, text :: String.t()) :: state
   @callback handle_expr(state, marker :: String.t(), expr :: Macro.t()) :: state
-
-  @doc """
-  Invoked at the beginning of every nesting.
-
-  It must return a new state that is used only inside the nesting.
-  Once the nesting terminates, the current `state` is resumed.
-  """
   @callback handle_begin(state) :: state
-
-  @doc """
-  Invokes at the end of a nesting.
-
-  It must return Elixir's quoted expressions for the nesting.
-  """
   @callback handle_end(state) :: Macro.t()
 
   @doc false
-  @deprecated "Use explicit delegation to EEx.Engine instead"
   defmacro __using__(_) do
     quote do
       @behaviour EEx.Engine
@@ -77,24 +65,24 @@ defmodule EEx.Engine do
         EEx.Engine.init(opts)
       end
 
-      def handle_body(state) do
-        EEx.Engine.handle_body(state)
+      def handle_body(quoted) do
+        EEx.Engine.handle_body(quoted)
       end
 
-      def handle_begin(state) do
-        EEx.Engine.handle_begin(state)
+      def handle_begin(quoted) do
+        EEx.Engine.handle_begin(quoted)
       end
 
-      def handle_end(state) do
-        EEx.Engine.handle_end(state)
+      def handle_end(quoted) do
+        EEx.Engine.handle_end(quoted)
       end
 
-      def handle_text(state, text) do
-        EEx.Engine.handle_text(state, [], text)
+      def handle_text(buffer, text) do
+        EEx.Engine.handle_text(buffer, text)
       end
 
-      def handle_expr(state, marker, expr) do
-        EEx.Engine.handle_expr(state, marker, expr)
+      def handle_expr(buffer, marker, expr) do
+        EEx.Engine.handle_expr(buffer, marker, expr)
       end
 
       defoverridable EEx.Engine
@@ -110,9 +98,9 @@ defmodule EEx.Engine do
   This can be added to any custom engine by invoking
   `handle_assign/1` with `Macro.prewalk/2`:
 
-      def handle_expr(state, token, expr) do
+      def handle_expr(buffer, token, expr) do
         expr = Macro.prewalk(expr, &EEx.Engine.handle_assign/1)
-        super(state, token, expr)
+        EEx.Engine.handle_expr(buffer, token, expr)
       end
 
   """
@@ -127,7 +115,7 @@ defmodule EEx.Engine do
   end
 
   @doc false
-  # TODO: Raise on v2.0
+  # TODO: Raise on 2.0
   @spec fetch_assign!(Access.t(), Access.key()) :: term | nil
   def fetch_assign!(assigns, key) do
     case Access.fetch(assigns, key) do
@@ -147,75 +135,68 @@ defmodule EEx.Engine do
     end
   end
 
-  @doc "Default implementation for `c:init/1`."
+  @doc """
+  Returns an empty string as initial buffer.
+  """
   def init(_opts) do
-    %{
-      binary: [],
-      dynamic: [],
-      vars_count: 0
-    }
+    ""
   end
 
-  @doc "Default implementation for `c:handle_begin/1`."
-  def handle_begin(state) do
-    check_state!(state)
-    %{state | binary: [], dynamic: []}
+  @doc """
+  Returns an empty string as the new buffer.
+  """
+  def handle_begin(_previous) do
+    ""
   end
 
-  @doc "Default implementation for `c:handle_end/1`."
+  @doc """
+  End of the new buffer.
+  """
   def handle_end(quoted) do
-    handle_body(quoted)
+    quoted
   end
 
-  @doc "Default implementation for `c:handle_body/1`."
-  def handle_body(state) do
-    check_state!(state)
-    %{binary: binary, dynamic: dynamic} = state
-    binary = {:<<>>, [], Enum.reverse(binary)}
-    dynamic = [binary | dynamic]
-    {:__block__, [], Enum.reverse(dynamic)}
+  @doc """
+  The default implementation simply returns the given expression.
+  """
+  def handle_body(quoted) do
+    quoted
   end
 
-  @doc "Default implementation for `c:handle_text/3`."
-  def handle_text(state, _meta, text) do
-    check_state!(state)
-    %{binary: binary} = state
-    %{state | binary: [text | binary]}
+  @doc """
+  The default implementation simply concatenates text to the buffer.
+  """
+  def handle_text(buffer, text) do
+    quote(do: unquote(buffer) <> unquote(text))
   end
 
-  @doc "Default implementation for `c:handle_expr/3`."
-  def handle_expr(state, "=", ast) do
-    check_state!(state)
-    %{binary: binary, dynamic: dynamic, vars_count: vars_count} = state
-    var = Macro.var(:"arg#{vars_count}", __MODULE__)
+  @doc """
+  Implements expressions according to the markers.
 
-    ast =
-      quote do
-        unquote(var) = String.Chars.to_string(unquote(ast))
-      end
+      <% Elixir expression - inline with output %>
+      <%= Elixir expression - replace with result %>
+      <%/ Elixir expression - raise EEx.SyntaxError, to be implemented by custom engines %>
+      <%| Elixir expression - raise EEx.SyntaxError, to be implemented by custom engines %>
 
-    segment =
-      quote do
-        unquote(var) :: binary
-      end
-
-    %{state | dynamic: [ast | dynamic], binary: [segment | binary], vars_count: vars_count + 1}
+  All other markers are not implemented by this engine.
+  """
+  def handle_expr(buffer, "=", expr) do
+    quote do
+      tmp1 = unquote(buffer)
+      tmp1 <> String.Chars.to_string(unquote(expr))
+    end
   end
 
-  def handle_expr(state, "", ast) do
-    %{dynamic: dynamic} = state
-    %{state | dynamic: [ast | dynamic]}
+  def handle_expr(buffer, "", expr) do
+    quote do
+      tmp2 = unquote(buffer)
+      unquote(expr)
+      tmp2
+    end
   end
 
-  def handle_expr(_state, marker, _ast) when marker in ["/", "|"] do
+  def handle_expr(_buffer, marker, _expr) when marker in ["/", "|"] do
     raise EEx.SyntaxError,
           "unsupported EEx syntax <%#{marker} %> (the syntax is valid but not supported by the current EEx engine)"
   end
-
-  defp check_state!(%{binary: _, dynamic: _, vars_count: _}), do: :ok
-
-  defp check_state!(state) do
-    raise "unexpected EEx.Engine state: #{inspect(state)}. " <>
-            "This typically means a bug or an outdated EEx.Engine or tool"
-  end
 end

lib/eex/lib/eex/smart_engine.ex

@@ -24,35 +24,18 @@ defmodule EEx.SmartEngine do
       # sample.ex
       defmodule Sample do
         require EEx
-        EEx.function_from_file(:def, :sample, "sample.eex", [:assigns])
+        EEx.function_from_file :def, :sample, "sample.eex", [:assigns]
       end
 
       # iex
-      Sample.sample(a: 1, b: 2)
-      #=> "3"
+      Sample.sample(a: 1, b: 2) #=> "3"
 
   """
 
-  @behaviour EEx.Engine
+  use EEx.Engine
 
-  @impl true
-  defdelegate init(opts), to: EEx.Engine
-
-  @impl true
-  defdelegate handle_body(state), to: EEx.Engine
-
-  @impl true
-  defdelegate handle_begin(state), to: EEx.Engine
-
-  @impl true
-  defdelegate handle_end(state), to: EEx.Engine
-
-  @impl true
-  defdelegate handle_text(state, meta, text), to: EEx.Engine
-
-  @impl true
-  def handle_expr(state, marker, expr) do
+  def handle_expr(buffer, mark, expr) do
     expr = Macro.prewalk(expr, &EEx.Engine.handle_assign/1)
-    EEx.Engine.handle_expr(state, marker, expr)
+    super(buffer, mark, expr)
   end
 end

lib/eex/lib/eex/tokenizer.ex

@@ -0,0 +1,231 @@
+defmodule EEx.Tokenizer do
+  @moduledoc false
+
+  @type content :: IO.chardata()
+  @type line :: non_neg_integer
+  @type marker :: '=' | '/' | '|' | ''
+  @type token ::
+          {:text, content}
+          | {:expr | :start_expr | :middle_expr | :end_expr, line, marker, content}
+
+  @doc """
+  Tokenizes the given charlist or binary.
+
+  It returns {:ok, list} with the following tokens:
+
+    * `{:text, content}`
+    * `{:expr, line, marker, content}`
+    * `{:start_expr, line, marker, content}`
+    * `{:middle_expr, line, marker, content}`
+    * `{:end_expr, line, marker, content}`
+
+  Or `{:error, line, error}` in case of errors.
+  """
+  @spec tokenize(binary | charlist, line, keyword) :: {:ok, [token]} | {:error, line, String.t()}
+  def tokenize(bin, line, opts \\ [])
+
+  def tokenize(bin, line, opts)
+      when is_binary(bin) and is_integer(line) and line >= 0 and is_list(opts) do
+    tokenize(String.to_charlist(bin), line, opts)
+  end
+
+  def tokenize(list, line, opts)
+      when is_list(list) and is_integer(line) and line >= 0 and is_list(opts) do
+    tokenize(list, line, opts, [], [])
+  end
+
+  defp tokenize('<%%' ++ t, line, opts, buffer, acc) do
+    tokenize(t, line, opts, [?%, ?< | buffer], acc)
+  end
+
+  defp tokenize('<%#' ++ t, line, opts, buffer, acc) do
+    case expr(t, line, []) do
+      {:error, _, _} = error ->
+        error
+
+      {:ok, _, new_line, rest} ->
+        {rest, new_line, buffer} = trim_if_needed(rest, new_line, opts, buffer, acc)
+        tokenize(rest, new_line, opts, buffer, acc)
+    end
+  end
+
+  defp tokenize('<%' ++ t, line, opts, buffer, acc) do
+    {marker, t} = retrieve_marker(t)
+
+    case expr(t, line, []) do
+      {:error, _, _} = error ->
+        error
+
+      {:ok, expr, new_line, rest} ->
+        token = token_name(expr)
+        {rest, new_line, buffer} = trim_if_needed(rest, new_line, opts, buffer, acc)
+        acc = tokenize_text(buffer, acc)
+        final = {token, line, marker, Enum.reverse(expr)}
+        tokenize(rest, new_line, opts, [], [final | acc])
+    end
+  end
+
+  defp tokenize('\n' ++ t, line, opts, buffer, acc) do
+    tokenize(t, line + 1, opts, [?\n | buffer], acc)
+  end
+
+  defp tokenize([h | t], line, opts, buffer, acc) do
+    tokenize(t, line, opts, [h | buffer], acc)
+  end
+
+  defp tokenize([], _line, _opts, buffer, acc) do
+    {:ok, Enum.reverse(tokenize_text(buffer, acc))}
+  end
+
+  # Retrieve marker for <%
+
+  defp retrieve_marker([marker | t]) when marker in [?=, ?/, ?|] do
+    {[marker], t}
+  end
+
+  defp retrieve_marker(t) do
+    {'', t}
+  end
+
+  # Tokenize an expression until we find %>
+
+  defp expr([?%, ?> | t], line, buffer) do
+    {:ok, buffer, line, t}
+  end
+
+  defp expr('\n' ++ t, line, buffer) do
+    expr(t, line + 1, [?\n | buffer])
+  end
+
+  defp expr([h | t], line, buffer) do
+    expr(t, line, [h | buffer])
+  end
+
+  defp expr([], line, _buffer) do
+    {:error, line, "missing token '%>'"}
+  end
+
+  # Receive an expression content and check
+  # if it is a start, middle or an end token.
+  #
+  # Start tokens finish with "do" and "fn ->"
+  # Middle tokens are marked with "->" or keywords
+  # End tokens contain only the end word and optionally ")"
+
+  defp token_name([h | t]) when h in [?\s, ?\t, ?)] do
+    token_name(t)
+  end
+
+  defp token_name('od' ++ [h | _]) when h in [?\s, ?\t, ?)] do
+    :start_expr
+  end
+
+  defp token_name('>-' ++ rest) do
+    rest = Enum.reverse(rest)
+
+    # Tokenize the remaining passing check_terminators as
+    # false, which relax the tokenizer to not error on
+    # unmatched pairs. Then, we check if there is a "fn"
+    # token and, if so, it is not followed by an "end"
+    # token. If this is the case, we are on a start expr.
+    case :elixir_tokenizer.tokenize(rest, 1, file: "eex", check_terminators: false) do
+      {:ok, tokens} ->
+        tokens = Enum.reverse(tokens)
+        fn_index = fn_index(tokens)
+
+        if fn_index && end_index(tokens) > fn_index do
+          :start_expr
+        else
+          :middle_expr
+        end
+
+      _error ->
+        :middle_expr
+    end
+  end
+
+  defp token_name('esle' ++ t), do: check_spaces(t, :middle_expr)
+  defp token_name('retfa' ++ t), do: check_spaces(t, :middle_expr)
+  defp token_name('hctac' ++ t), do: check_spaces(t, :middle_expr)
+  defp token_name('eucser' ++ t), do: check_spaces(t, :middle_expr)
+  defp token_name('dne' ++ t), do: check_spaces(t, :end_expr)
+
+  defp token_name(_) do
+    :expr
+  end
+
+  defp fn_index(tokens) do
+    Enum.find_index(tokens, fn
+      {:fn_paren, _} -> true
+      {:fn, _} -> true
+      _ -> false
+    end)
+  end
+
+  defp end_index(tokens) do
+    Enum.find_index(tokens, &match?({:end, _}, &1)) || :infinity
+  end
+
+  defp check_spaces(string, token) do
+    if Enum.all?(string, &(&1 in [?\s, ?\t])) do
+      token
+    else
+      :expr
+    end
+  end
+
+  # Tokenize the buffered text by appending
+  # it to the given accumulator.
+
+  defp tokenize_text([], acc) do
+    acc
+  end
+
+  defp tokenize_text(buffer, acc) do
+    [{:text, Enum.reverse(buffer)} | acc]
+  end
+
+  # If trim mode is enabled and the token is on a line with
+  # only itself and whitespace, trim the whitespace around it,
+  # including the line break following it if there is one.
+  defp trim_if_needed(rest, line, opts, buffer, acc) do
+    original = {rest, line, buffer}
+
+    if opts[:trim] do
+      case {trim_left(buffer, acc), trim_right(rest, line)} do
+        {{true, new_buffer}, {true, new_rest, new_line}} ->
+          {new_rest, new_line, new_buffer}
+
+        _ ->
+          original
+      end
+    else
+      original
+    end
+  end
+
+  defp trim_left(buffer, acc) do
+    case {trim_whitespace(buffer), acc} do
+      {[?\n | _] = trimmed_buffer, _} -> {true, trimmed_buffer}
+      {[], []} -> {true, []}
+      _ -> {false, buffer}
+    end
+  end
+
+  defp trim_right(rest, line) do
+    case trim_whitespace(rest) do
+      [?\r, ?\n | trimmed_rest] -> {true, trimmed_rest, line + 1}
+      [?\n | trimmed_rest] -> {true, trimmed_rest, line + 1}
+      [] -> {true, [], line}
+      _ -> {false, rest, line}
+    end
+  end
+
+  defp trim_whitespace([h | t]) when h == ?\s or h == ?\t do
+    trim_whitespace(t)
+  end
+
+  defp trim_whitespace(list) do
+    list
+  end
+end

lib/eex/test/eex/smart_engine_test.exs

@@ -1,7 +1,8 @@
 Code.require_file("../test_helper.exs", __DIR__)
 
 defmodule EEx.SmartEngineTest do
-  use ExUnit.Case, async: true
+  # TODO: Make this async: true once capture_io is removed
+  use ExUnit.Case
 
   test "evaluates simple string" do
     assert_eval("foo bar", "foo bar")
@@ -28,28 +29,16 @@ defmodule EEx.SmartEngineTest do
     assert_eval("1\n2\n3\n", "<%= for x <- [1, 2, 3] do %><%= x %>\n<% end %>")
   end
 
-  test "preserves line numbers in assignments" do
-    result = EEx.compile_string("foo\n<%= @hello %>", engine: EEx.SmartEngine)
+  test "preserves line numbers" do
+    result = EEx.compile_string("<%= @hello %>", engine: EEx.SmartEngine)
 
     Macro.prewalk(result, fn
-      {_left, meta, [_, :hello]} ->
-        assert Keyword.get(meta, :line) == 2
-        send(self(), :found)
+      {_left, meta, _right} ->
+        assert Keyword.get(meta, :line, 0) in [0, 1]
 
-      node ->
-        node
+      _ ->
+        :ok
     end)
-
-    assert_received :found
-  end
-
-  test "error with unused \"do\" block without \"<%=\" modifier" do
-    stderr =
-      ExUnit.CaptureIO.capture_io(:stderr, fn ->
-        assert_eval("", "<% if true do %>I'm invisible!<% end %>", assigns: %{})
-      end)
-
-    assert stderr =~ "the contents of this expression won't be output"
   end
 
   defp assert_eval(expected, actual, binding \\ []) do

lib/eex/test/eex/tokenizer_test.exs

@@ -2,67 +2,34 @@ Code.require_file("../test_helper.exs", __DIR__)
 
 defmodule EEx.TokenizerTest do
   use ExUnit.Case, async: true
-
-  @opts [indentation: 0, trim: false]
+  require EEx.Tokenizer, as: T
 
   test "simple chars lists" do
-    assert EEx.tokenize('foo', @opts) ==
-             {:ok, [{:text, 'foo', %{column: 1, line: 1}}, {:eof, %{column: 4, line: 1}}]}
+    assert T.tokenize('foo', 1) == {:ok, [{:text, 'foo'}]}
   end
 
   test "simple strings" do
-    assert EEx.tokenize("foo", @opts) ==
-             {:ok, [{:text, 'foo', %{column: 1, line: 1}}, {:eof, %{column: 4, line: 1}}]}
+    assert T.tokenize("foo", 1) == {:ok, [{:text, 'foo'}]}
   end
 
   test "strings with embedded code" do
-    assert EEx.tokenize('foo <% bar %>', @opts) ==
-             {:ok,
-              [
-                {:text, 'foo ', %{column: 1, line: 1}},
-                {:expr, '', ' bar ', %{column: 5, line: 1}},
-                {:eof, %{column: 14, line: 1}}
-              ]}
+    assert T.tokenize('foo <% bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '', ' bar '}]}
   end
 
   test "strings with embedded equals code" do
-    assert EEx.tokenize('foo <%= bar %>', @opts) ==
-             {:ok,
-              [
-                {:text, 'foo ', %{column: 1, line: 1}},
-                {:expr, '=', ' bar ', %{column: 5, line: 1}},
-                {:eof, %{column: 15, line: 1}}
-              ]}
+    assert T.tokenize('foo <%= bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '=', ' bar '}]}
   end
 
   test "strings with embedded slash code" do
-    assert EEx.tokenize('foo <%/ bar %>', @opts) ==
-             {:ok,
-              [
-                {:text, 'foo ', %{column: 1, line: 1}},
-                {:expr, '/', ' bar ', %{column: 5, line: 1}},
-                {:eof, %{column: 15, line: 1}}
-              ]}
+    assert T.tokenize('foo <%/ bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '/', ' bar '}]}
   end
 
   test "strings with embedded pipe code" do
-    assert EEx.tokenize('foo <%| bar %>', @opts) ==
-             {:ok,
-              [
-                {:text, 'foo ', %{column: 1, line: 1}},
-                {:expr, '|', ' bar ', %{column: 5, line: 1}},
-                {:eof, %{column: 15, line: 1}}
-              ]}
+    assert T.tokenize('foo <%| bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '|', ' bar '}]}
   end
 
   test "strings with more than one line" do
-    assert EEx.tokenize('foo\n<%= bar %>', @opts) ==
-             {:ok,
-              [
-                {:text, 'foo\n', %{column: 1, line: 1}},
-                {:expr, '=', ' bar ', %{column: 1, line: 2}},
-                {:eof, %{column: 11, line: 2}}
-              ]}
+    assert T.tokenize('foo\n<%= bar %>', 1) == {:ok, [{:text, 'foo\n'}, {:expr, 2, '=', ' bar '}]}
   end
 
   test "strings with more than one line and expression with more than one line" do
@@ -74,298 +41,144 @@ defmodule EEx.TokenizerTest do
     '''
 
     exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:expr, '=', ' bar\n\nbaz ', %{column: 5, line: 1}},
-      {:text, '\n', %{column: 7, line: 3}},
-      {:expr, '', ' foo ', %{column: 1, line: 4}},
-      {:text, '\n', %{column: 10, line: 4}},
-      {:eof, %{column: 1, line: 5}}
+      {:text, 'foo '},
+      {:expr, 1, '=', ' bar\n\nbaz '},
+      {:text, '\n'},
+      {:expr, 4, '', ' foo '},
+      {:text, '\n'}
     ]
 
-    assert EEx.tokenize(string, @opts) == {:ok, exprs}
+    assert T.tokenize(string, 1) == {:ok, exprs}
   end
 
   test "quotation" do
-    assert EEx.tokenize('foo <%% true %>', @opts) ==
-             {:ok,
-              [
-                {:text, 'foo <% true %>', %{column: 1, line: 1}},
-                {:eof, %{column: 16, line: 1}}
-              ]}
+    assert T.tokenize('foo <%% true %>', 1) == {:ok, [{:text, 'foo <% true %>'}]}
   end
 
-  test "quotation with do-end" do
-    assert EEx.tokenize('foo <%% true do %>bar<%% end %>', @opts) ==
-             {:ok,
-              [
-                {:text, 'foo <% true do %>bar<% end %>', %{column: 1, line: 1}},
-                {:eof, %{column: 32, line: 1}}
-              ]}
+  test "quotation with do/end" do
+    assert T.tokenize('foo <%% true do %>bar<%% end %>', 1) ==
+             {:ok, [{:text, 'foo <% true do %>bar<% end %>'}]}
   end
 
   test "quotation with interpolation" do
     exprs = [
-      {:text, 'a <% b ', %{column: 1, line: 1}},
-      {:expr, '=', ' c ', %{column: 9, line: 1}},
-      {:text, ' ', %{column: 17, line: 1}},
-      {:expr, '=', ' d ', %{column: 18, line: 1}},
-      {:text, ' e %> f', %{column: 26, line: 1}},
-      {:eof, %{column: 33, line: 1}}
+      {:text, 'a <% b '},
+      {:expr, 1, '=', ' c '},
+      {:text, ' '},
+      {:expr, 1, '=', ' d '},
+      {:text, ' e %> f'}
     ]
 
-    assert EEx.tokenize('a <%% b <%= c %> <%= d %> e %> f', @opts) == {:ok, exprs}
+    assert T.tokenize('a <%% b <%= c %> <%= d %> e %> f', 1) == {:ok, exprs}
   end
 
   test "improperly formatted quotation with interpolation" do
     exprs = [
-      {:text, '<%% a <%= b %> c %>', %{column: 1, line: 1}},
-      {:eof, %{column: 22, line: 1}}
+      {:text, '<%% a <%= b %> c %>'}
     ]
 
-    assert EEx.tokenize('<%%% a <%%= b %> c %>', @opts) == {:ok, exprs}
+    assert T.tokenize('<%%% a <%%= b %> c %>', 1) == {:ok, exprs}
   end
 
-  test "EEx comments" do
+  test "comments" do
     exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:eof, %{column: 16, line: 1}}
+      {:text, 'foo '}
     ]
 
-    assert EEx.tokenize('foo <%# true %>', @opts) == {:ok, exprs}
-
-    exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:eof, %{column: 8, line: 2}}
-    ]
-
-    assert EEx.tokenize('foo <%#\ntrue %>', @opts) == {:ok, exprs}
+    assert T.tokenize('foo <%# true %>', 1) == {:ok, exprs}
   end
 
-  test "EEx comments with do-end" do
+  test "comments with do/end" do
     exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:text, 'bar', %{column: 19, line: 1}},
-      {:eof, %{column: 32, line: 1}}
+      {:text, 'foo bar'}
     ]
 
-    assert EEx.tokenize('foo <%# true do %>bar<%# end %>', @opts) == {:ok, exprs}
-  end
-
-  test "EEx comments inside do-end" do
-    exprs = [
-      {:start_expr, '', ' if true do ', %{column: 1, line: 1}},
-      {:text, 'bar', %{column: 31, line: 1}},
-      {:end_expr, [], ' end ', %{column: 34, line: 1}},
-      {:eof, %{column: 43, line: 1}}
-    ]
-
-    assert EEx.tokenize('<% if true do %><%# comment %>bar<% end %>', @opts) == {:ok, exprs}
-
-    exprs = [
-      {:start_expr, [], ' case true do ', %{column: 1, line: 1}},
-      {:middle_expr, '', ' true -> ', %{column: 33, line: 1}},
-      {:text, 'bar', %{column: 46, line: 1}},
-      {:end_expr, [], ' end ', %{column: 49, line: 1}},
-      {:eof, %{column: 58, line: 1}}
-    ]
-
-    assert EEx.tokenize('<% case true do %><%# comment %><% true -> %>bar<% end %>', @opts) ==
-             {:ok, exprs}
-  end
-
-  test "EEx multi-line comments" do
-    exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:comment, ' true ', %{column: 5, line: 1}},
-      {:text, ' bar', %{column: 20, line: 1}},
-      {:eof, %{column: 24, line: 1}}
-    ]
-
-    assert EEx.tokenize('foo <%!-- true --%> bar', @opts) == {:ok, exprs}
-
-    exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:comment, ' \ntrue\n ', %{column: 5, line: 1}},
-      {:text, ' bar', %{column: 6, line: 3}},
-      {:eof, %{column: 10, line: 3}}
-    ]
-
-    assert EEx.tokenize('foo <%!-- \ntrue\n --%> bar', @opts) == {:ok, exprs}
-
-    exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:comment, ' <%= true %> ', %{column: 5, line: 1}},
-      {:text, ' bar', %{column: 27, line: 1}},
-      {:eof, %{column: 31, line: 1}}
-    ]
-
-    assert EEx.tokenize('foo <%!-- <%= true %> --%> bar', @opts) == {:ok, exprs}
-  end
-
-  test "Elixir comments" do
-    exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:expr, [], ' true # this is a boolean ', %{column: 5, line: 1}},
-      {:eof, %{column: 35, line: 1}}
-    ]
-
-    assert EEx.tokenize('foo <% true # this is a boolean %>', @opts) == {:ok, exprs}
-  end
-
-  test "Elixir comments with do-end" do
-    exprs = [
-      {:start_expr, [], ' if true do # startif ', %{column: 1, line: 1}},
-      {:text, 'text', %{column: 27, line: 1}},
-      {:end_expr, [], ' end # closeif ', %{column: 31, line: 1}},
-      {:eof, %{column: 50, line: 1}}
-    ]
-
-    assert EEx.tokenize('<% if true do # startif %>text<% end # closeif %>', @opts) ==
-             {:ok, exprs}
+    assert T.tokenize('foo <%# true do %>bar<%# end %>', 1) == {:ok, exprs}
   end
 
   test "strings with embedded do end" do
     exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:start_expr, '', ' if true do ', %{column: 5, line: 1}},
-      {:text, 'bar', %{column: 21, line: 1}},
-      {:end_expr, '', ' end ', %{column: 24, line: 1}},
-      {:eof, %{column: 33, line: 1}}
+      {:text, 'foo '},
+      {:start_expr, 1, '', ' if true do '},
+      {:text, 'bar'},
+      {:end_expr, 1, '', ' end '}
     ]
 
-    assert EEx.tokenize('foo <% if true do %>bar<% end %>', @opts) == {:ok, exprs}
+    assert T.tokenize('foo <% if true do %>bar<% end %>', 1) == {:ok, exprs}
   end
 
   test "strings with embedded -> end" do
     exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:start_expr, '', ' cond do ', %{column: 5, line: 1}},
-      {:middle_expr, '', ' false -> ', %{column: 18, line: 1}},
-      {:text, 'bar', %{column: 32, line: 1}},
-      {:middle_expr, '', ' true -> ', %{column: 35, line: 1}},
-      {:text, 'baz', %{column: 48, line: 1}},
-      {:end_expr, '', ' end ', %{column: 51, line: 1}},
-      {:eof, %{column: 60, line: 1}}
+      {:text, 'foo '},
+      {:start_expr, 1, '', ' cond do '},
+      {:middle_expr, 1, '', ' false -> '},
+      {:text, 'bar'},
+      {:middle_expr, 1, '', ' true -> '},
+      {:text, 'baz'},
+      {:end_expr, 1, '', ' end '}
     ]
 
-    assert EEx.tokenize('foo <% cond do %><% false -> %>bar<% true -> %>baz<% end %>', @opts) ==
+    assert T.tokenize('foo <% cond do %><% false -> %>bar<% true -> %>baz<% end %>', 1) ==
              {:ok, exprs}
   end
 
-  test "strings with fn-end with newline" do
-    exprs = [
-      {:start_expr, '=', ' a fn ->\n', %{column: 1, line: 1}},
-      {:text, 'foo', %{column: 3, line: 2}},
-      {:end_expr, [], ' end ', %{column: 6, line: 2}},
-      {:eof, %{column: 15, line: 2}}
-    ]
-
-    assert EEx.tokenize('<%= a fn ->\n%>foo<% end %>', @opts) ==
-             {:ok, exprs}
-  end
-
-  test "strings with multiple fn-end" do
-    exprs = [
-      {:start_expr, '=', ' a fn -> ', %{column: 1, line: 1}},
-      {:text, 'foo', %{column: 15, line: 1}},
-      {:middle_expr, '', ' end, fn -> ', %{column: 18, line: 1}},
-      {:text, 'bar', %{column: 34, line: 1}},
-      {:end_expr, '', ' end ', %{column: 37, line: 1}},
-      {:eof, %{column: 46, line: 1}}
-    ]
-
-    assert EEx.tokenize('<%= a fn -> %>foo<% end, fn -> %>bar<% end %>', @opts) ==
-             {:ok, exprs}
-  end
-
-  test "strings with fn-end followed by do block" do
-    exprs = [
-      {:start_expr, '=', ' a fn -> ', %{column: 1, line: 1}},
-      {:text, 'foo', %{column: 15, line: 1}},
-      {:middle_expr, '', ' end do ', %{column: 18, line: 1}},
-      {:text, 'bar', %{column: 30, line: 1}},
-      {:end_expr, '', ' end ', %{column: 33, line: 1}},
-      {:eof, %{column: 42, line: 1}}
-    ]
-
-    assert EEx.tokenize('<%= a fn -> %>foo<% end do %>bar<% end %>', @opts) == {:ok, exprs}
-  end
-
   test "strings with embedded keywords blocks" do
     exprs = [
-      {:text, 'foo ', %{column: 1, line: 1}},
-      {:start_expr, '', ' if true do ', %{column: 5, line: 1}},
-      {:text, 'bar', %{column: 21, line: 1}},
-      {:middle_expr, '', ' else ', %{column: 24, line: 1}},
-      {:text, 'baz', %{column: 34, line: 1}},
-      {:end_expr, '', ' end ', %{column: 37, line: 1}},
-      {:eof, %{column: 46, line: 1}}
+      {:text, 'foo '},
+      {:start_expr, 1, '', ' if true do '},
+      {:text, 'bar'},
+      {:middle_expr, 1, '', ' else '},
+      {:text, 'baz'},
+      {:end_expr, 1, '', ' end '}
     ]
 
-    assert EEx.tokenize('foo <% if true do %>bar<% else %>baz<% end %>', @opts) ==
-             {:ok, exprs}
+    assert T.tokenize('foo <% if true do %>bar<% else %>baz<% end %>', 1) == {:ok, exprs}
   end
 
   test "trim mode" do
-    template = '\t<%= if true do %> \n TRUE \n  <% else %>\n FALSE \n  <% end %>  \n\n  '
+    template = '\t<%= if true do %> \n TRUE \n  <% else %>\n FALSE \n  <% end %>  '
 
     exprs = [
-      {:start_expr, '=', ' if true do ', %{column: 2, line: 1}},
-      {:text, '\n TRUE \n', %{column: 20, line: 1}},
-      {:middle_expr, '', ' else ', %{column: 3, line: 3}},
-      {:text, '\n FALSE \n', %{column: 13, line: 3}},
-      {:end_expr, '', ' end ', %{column: 3, line: 5}},
-      {:eof, %{column: 3, line: 7}}
+      {:start_expr, 1, '=', ' if true do '},
+      {:text, ' TRUE \n'},
+      {:middle_expr, 3, '', ' else '},
+      {:text, ' FALSE \n'},
+      {:end_expr, 5, '', ' end '}
     ]
 
-    assert EEx.tokenize(template, [trim: true] ++ @opts) == {:ok, exprs}
+    assert T.tokenize(template, 1, trim: true) == {:ok, exprs}
   end
 
   test "trim mode with comment" do
     exprs = [
-      {:text, '\n123', %{column: 19, line: 1}},
-      {:eof, %{column: 4, line: 2}}
+      {:text, '123'}
     ]
 
-    assert EEx.tokenize('  <%# comment %>  \n123', [trim: true] ++ @opts) == {:ok, exprs}
-  end
-
-  test "trim mode with multi-line comment" do
-    exprs = [
-      {:comment, ' comment ', %{column: 3, line: 1}},
-      {:text, '\n123', %{column: 23, line: 1}},
-      {:eof, %{column: 4, line: 2}}
-    ]
-
-    assert EEx.tokenize('  <%!-- comment --%>  \n123', [trim: true] ++ @opts) == {:ok, exprs}
+    assert T.tokenize('  <%# comment %>  \n123', 1, trim: true) == {:ok, exprs}
   end
 
   test "trim mode with CRLF" do
     exprs = [
-      {:text, '0\n', %{column: 1, line: 1}},
-      {:expr, '=', ' 12 ', %{column: 3, line: 2}},
-      {:text, '\n34', %{column: 15, line: 2}},
-      {:eof, %{column: 3, line: 3}}
+      {:text, '0\r\n'},
+      {:expr, 2, '=', ' 12 '},
+      {:text, '34'}
     ]
 
-    assert EEx.tokenize('0\r\n  <%= 12 %>  \r\n34', [trim: true] ++ @opts) == {:ok, exprs}
+    assert T.tokenize('0\r\n  <%= 12 %>  \r\n34', 1, trim: true) == {:ok, exprs}
   end
 
   test "trim mode set to false" do
     exprs = [
-      {:text, ' ', %{column: 1, line: 1}},
-      {:expr, '=', ' 12 ', %{column: 2, line: 1}},
-      {:text, ' \n', %{column: 11, line: 1}},
-      {:eof, %{column: 1, line: 2}}
+      {:text, ' '},
+      {:expr, 1, '=', ' 12 '},
+      {:text, ' \n'}
     ]
 
-    assert EEx.tokenize(' <%= 12 %> \n', [trim: false] ++ @opts) == {:ok, exprs}
+    assert T.tokenize(' <%= 12 %> \n', 1, trim: false) == {:ok, exprs}
   end
 
   test "trim mode no false positives" do
-    assert_not_trimmed = fn x ->
-      assert EEx.tokenize(x, [trim: false] ++ @opts) == EEx.tokenize(x, @opts)
-    end
+    assert_not_trimmed = fn x -> assert T.tokenize(x, 1, trim: true) == T.tokenize(x, 1) end
 
     assert_not_trimmed.('foo <%= "bar" %>  ')
     assert_not_trimmed.('\n  <%= "foo" %>bar')
@@ -373,23 +186,8 @@ defmodule EEx.TokenizerTest do
     assert_not_trimmed.('  <%= 01 %><%= 23 %>\n')
   end
 
-  test "returns error when there is start mark and no end mark" do
-    assert EEx.tokenize('foo <% :bar', @opts) ==
-             {:error, "missing token '%>'", %{column: 12, line: 1}}
-
-    assert EEx.tokenize('<%# true ', @opts) ==
-             {:error, "missing token '%>'", %{column: 10, line: 1}}
-
-    assert EEx.tokenize('<%!-- foo ', @opts) ==
-             {:error, "missing token '--%>'", %{column: 11, line: 1}}
-  end
-
-  test "marks invalid expressions as regular expressions" do
-    assert EEx.tokenize('<% 1 $ 2 %>', @opts) ==
-             {:ok,
-              [
-                {:expr, [], ' 1 $ 2 ', %{column: 1, line: 1}},
-                {:eof, %{column: 12, line: 1}}
-              ]}
+  test "raise syntax error when there is start mark and no end mark" do
+    assert T.tokenize('foo <% :bar', 1) == {:error, 1, "missing token '%>'"}
+    assert T.tokenize('<%# true ', 1) == {:error, 1, "missing token '%>'"}
   end
 end

lib/eex/test/eex_test.exs

@@ -64,43 +64,9 @@ defmodule EExTest do
       assert_eval("  • • •\n  Jößé Vâlìm Jößé Vâlìm\n", template)
     end
 
-    test "no spaces" do
-      string = """
-      <%=cond do%>
-      <%false ->%>
-        this
-      <%true ->%>
-        that
-      <%end%>
-      """
-
-      expected = "\n  that\n\n"
-      assert_eval(expected, string, [])
-    end
-
     test "trim mode" do
-      string = "<%= 123 %> \n  \n  <%= 789 %>"
-      expected = "123\n789"
-      assert_eval(expected, string, [], trim: true)
-
       string = "<%= 123 %> \n456\n  <%= 789 %>"
-      expected = "123\n456\n789"
-      assert_eval(expected, string, [], trim: true)
-
-      string = "<%= 123 %> \n\n456\n\n  <%= 789 %>"
-      expected = "123\n456\n789"
-      assert_eval(expected, string, [], trim: true)
-
-      string = "<%= 123 %> \n  \n456\n  \n  <%= 789 %>"
-      expected = "123\n456\n789"
-      assert_eval(expected, string, [], trim: true)
-
-      string = "\n  <%= 123 %> \n  <%= 456 %>  \n  <%= 789 %>  \n"
-      expected = "123\n456\n789"
-      assert_eval(expected, string, [], trim: true)
-
-      string = "\r\n  <%= 123 %> \r\n  <%= 456 %>  \r\n  <%= 789 %>  \r\n"
-      expected = "123\n456\n789"
+      expected = "123456\n789"
       assert_eval(expected, string, [], trim: true)
     end
 
@@ -114,44 +80,7 @@ defmodule EExTest do
       <% end %>
       """
 
-      expected = "\n  that\n"
-      assert_eval(expected, string, [], trim: true)
-    end
-
-    test "trim mode with multiple lines" do
-      string = """
-      <%= "First line" %>
-      <%= "Second line" %>
-      <%= "Third line" %>
-      <%= "Fourth line" %>
-      """
-
-      expected = "First line\nSecond line\nThird line\nFourth line"
-      assert_eval(expected, string, [], trim: true)
-    end
-
-    test "trim mode with no spaces" do
-      string = """
-      <%=if true do%>
-        this
-      <%else%>
-        that
-      <%end%>
-      """
-
-      expected = "\n  this\n"
-      assert_eval(expected, string, [], trim: true)
-
-      string = """
-      <%=cond do%>
-      <%false ->%>
-        this
-      <%true ->%>
-        that
-      <%end%>
-      """
-
-      expected = "\n  that\n"
+      expected = "  that\n"
       assert_eval(expected, string, [], trim: true)
     end
 
@@ -171,12 +100,6 @@ defmodule EExTest do
       assert_eval("foo ", "foo <%= if false do %>bar<% end %>")
     end
 
-    test "embedded code with do preceded by bracket" do
-      assert_eval("foo bar", "foo <%= if {true}do %>bar<% end %>")
-      assert_eval("foo bar", "foo <%= if (true)do %>bar<% end %>")
-      assert_eval("foo bar", "foo <%= if [true]do %>bar<% end %>")
-    end
-
     test "embedded code with do end and expression" do
       assert_eval("foo bar", "foo <%= if true do %><%= :bar %><% end %>")
     end
@@ -198,24 +121,6 @@ defmodule EExTest do
       assert_eval("foo baz", "foo <%= if false do %>bar<% else %>baz<% end %>")
     end
 
-    test "embedded code with comments in do end" do
-      assert_eval("foo bar", "foo <%= case true do %><%# comment %><% true -> %>bar<% end %>")
-
-      assert_eval(
-        "foo\n\nbar\n",
-        "foo\n<%= case true do %>\n<%# comment %>\n<% true -> %>\nbar\n<% end %>"
-      )
-    end
-
-    test "embedded code with multi-line comments in do end" do
-      assert_eval("foo bar", "foo <%= case true do %><%!-- comment --%><% true -> %>bar<% end %>")
-
-      assert_eval(
-        "foo\n\nbar\n",
-        "foo\n<%= case true do %>\n<%!-- comment --%>\n<% true -> %>\nbar\n<% end %>"
-      )
-    end
-
     test "embedded code with nested do end" do
       assert_eval("foo bar", "foo <%= if true do %><%= if true do %>bar<% end %><% end %>")
     end
@@ -227,32 +132,7 @@ defmodule EExTest do
       )
     end
 
-    test "embedded code with end followed by bracket" do
-      assert_eval(
-        " 101  102  103 ",
-        "<%= Enum.map([1, 2, 3], fn x -> %> <%= 100 + x %> <% end) %>"
-      )
-
-      assert_eval(
-        " 101  102  103 ",
-        "<%= Enum.map([1, 2, 3], fn x ->\n%> <%= 100 + x %> <% end) %>"
-      )
-
-      assert_eval(
-        " 101  102  103 ",
-        "<%= apply Enum, :map, [[1, 2, 3], fn x -> %> <%= 100 + x %> <% end] %>"
-      )
-
-      assert_eval(
-        " 101  102  103 ",
-        "<%= #{__MODULE__}.tuple_map {[1, 2, 3], fn x -> %> <%= 100 + x %> <% end} %>"
-      )
-
-      assert_eval(
-        " 101  102  103 ",
-        "<%= apply(Enum, :map, [[1, 2, 3], fn x -> %> <%= 100 + x %> <% end]) %>"
-      )
-
+    test "embedded code with parentheses after end in end token" do
       assert_eval(
         " 101  102  103 ",
         "<%= Enum.map([1, 2, 3], (fn x -> %> <%= 100 + x %> <% end) ) %>"
@@ -274,36 +154,34 @@ defmodule EExTest do
 
   describe "raises syntax errors" do
     test "when the token is invalid" do
-      assert_raise EEx.SyntaxError, "nofile:1:12: missing token '%>'", fn ->
+      assert_raise EEx.SyntaxError, "nofile:1: missing token '%>'", fn ->
         EEx.compile_string("foo <%= bar")
       end
     end
 
     test "when middle expression is found without a start expression" do
-      assert_raise EEx.SyntaxError,
-                   "nofile:1:18: unexpected middle of expression <% else %>",
-                   fn ->
-                     EEx.compile_string("<%= if true %>foo<% else %>bar<% end %>")
-                   end
+      assert_raise EEx.SyntaxError, "nofile:1: unexpected middle of expression <% else %>", fn ->
+        EEx.compile_string("<% if true %> foo<% else %>bar<% end %>")
+      end
     end
 
     test "when end expression is found without a start expression" do
-      assert_raise EEx.SyntaxError, "nofile:1:5: unexpected end of expression <% end %>", fn ->
+      assert_raise EEx.SyntaxError, "nofile:1: unexpected end of expression <% end %>", fn ->
         EEx.compile_string("foo <% end %>")
       end
     end
 
     test "when start expression is found without an end expression" do
-      msg = "nofile:2:18: unexpected end of string, expected a closing '<% end %>'"
+      msg = "nofile:2: unexpected end of string, expected a closing '<% end %>'"
 
       assert_raise EEx.SyntaxError, msg, fn ->
-        EEx.compile_string("foo\n<%= if true do %>")
+        EEx.compile_string("foo\n<% if true do %>")
       end
     end
 
     test "when nested end expression is found without a start expression" do
-      assert_raise EEx.SyntaxError, "nofile:1:31: unexpected end of expression <% end %>", fn ->
-        EEx.compile_string("foo <%= if true do %><% end %><% end %>")
+      assert_raise EEx.SyntaxError, "nofile:1: unexpected end of expression <% end %>", fn ->
+        EEx.compile_string("foo <% if true do %><% end %><% end %>")
       end
     end
 
@@ -317,7 +195,7 @@ defmodule EExTest do
       assert ExUnit.CaptureIO.capture_io(:stderr, fn ->
                EEx.compile_string("foo <%= if true do %>true<% else %>false<%= end %>")
              end) =~
-               ~s[unexpected beginning of EEx tag \"<%=\" on \"<%= end %>\"]
+               ~s[unexpected beginning of EEx tag \"<%=\" on end of expression \"<%= end %>\"]
     end
 
     test "when trying to use marker '/' without implementation" do
@@ -339,20 +217,6 @@ defmodule EExTest do
     end
   end
 
-  describe "error messages" do
-    test "honor line numbers" do
-      assert_raise EEx.SyntaxError, "nofile:99:12: missing token '%>'", fn ->
-        EEx.compile_string("foo <%= bar", line: 99)
-      end
-    end
-
-    test "honor file names" do
-      assert_raise EEx.SyntaxError, "my_file.eex:1:12: missing token '%>'", fn ->
-        EEx.compile_string("foo <%= bar", file: "my_file.eex")
-      end
-    end
-  end
-
   describe "environment" do
     test "respects line numbers" do
       expected = """
@@ -478,52 +342,6 @@ defmodule EExTest do
       assert_eval(expected, string)
     end
 
-    test "inside multiple functions" do
-      expected = """
-
-      A 1
-
-      B 2
-
-      A 3
-
-      """
-
-      string = """
-      <%= #{__MODULE__}.switching_map [1, 2, 3], fn x -> %>
-      A <%= x %>
-      <% end, fn x -> %>
-      B <%= x %>
-      <% end %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "inside callback and do block" do
-      expected = """
-
-
-      A 1
-
-      B 2
-
-      A 3
-
-      """
-
-      string = """
-      <% require #{__MODULE__} %>
-      <%= #{__MODULE__}.switching_macro [1, 2, 3], fn x -> %>
-      A <%= x %>
-      <% end do %>
-      B <%= x %>
-      <% end %>
-      """
-
-      assert_eval(expected, string)
-    end
-
     test "inside cond" do
       expected = """
       foo
@@ -551,51 +369,28 @@ defmodule EExTest do
        <% "a" in y -> %>
         Good
        <% true -> %>
-        <%= if true do %>true<% else %>false<% end %>
+        <% if true do %>true<% else %>false<% end %>
         Bad
       <% end %>
       """
 
       assert_eval("\n\n  Good\n \n", string)
     end
-
-    test "line and column meta" do
-      parser_options = Code.get_compiler_option(:parser_options)
-      Code.put_compiler_option(:parser_options, columns: true)
-
-      try do
-        indentation = 12
-
-        ast =
-          EEx.compile_string(
-            """
-            <%= f() %> <% f() %>
-              <%= f fn -> %>
-                <%= f() %>
-              <% end %>
-            """,
-            indentation: indentation
-          )
-
-        {_, calls} =
-          Macro.prewalk(ast, [], fn
-            {:f, meta, _args} = expr, acc -> {expr, [meta | acc]}
-            other, acc -> {other, acc}
-          end)
-
-        assert Enum.reverse(calls) == [
-                 [line: 1, column: indentation + 5],
-                 [line: 1, column: indentation + 15],
-                 [line: 2, column: indentation + 7],
-                 [line: 3, column: indentation + 9]
-               ]
-      after
-        Code.put_compiler_option(:parser_options, parser_options)
-      end
-    end
   end
 
   describe "buffers" do
+    test "unused buffers are kept out" do
+      string = """
+      <%= 123 %>
+      <% if true do %>
+        <%= 456 %>
+      <% end %>
+      <%= 789 %>
+      """
+
+      assert_eval("123\n\n789\n", string)
+    end
+
     test "inside comprehensions" do
       string = """
       <%= for _name <- packages || [] do %>
@@ -633,24 +428,6 @@ defmodule EExTest do
       assert EExTest.Compiled.__info__(:attributes)[:external_resource] ==
                [Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")]
     end
-
-    test "supports t:Path.t() paths" do
-      filename = to_charlist(Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex"))
-      result = EEx.eval_file(filename, bar: 1)
-      assert_normalized_newline_equal("foo 1\n", result)
-    end
-
-    assert_raise EEx.SyntaxError, "my_file.eex:1:12: missing token '%>'", fn ->
-      EEx.compile_string("foo <%= bar", file: "my_file.eex")
-    end
-
-    test "supports overriding file and line through options" do
-      filename = Path.join(__DIR__, "fixtures/eex_template_with_syntax_error.eex")
-
-      assert_raise EEx.SyntaxError, "my_file.eex:11:1: missing token '%>'", fn ->
-        EEx.eval_file(filename, _bindings = [], file: "my_file.eex", line: 10)
-      end
-    end
   end
 
   describe "precompiled" do
@@ -696,8 +473,8 @@ defmodule EExTest do
       buffer <> ":END"
     end
 
-    def handle_text(buffer, meta, text) do
-      buffer <> ":TEXT-#{meta[:line]}-#{meta[:column]}(#{String.trim(text)})"
+    def handle_text(buffer, text) do
+      buffer <> ":TEXT(#{String.trim(text)})"
     end
 
     def handle_expr(buffer, "/", expr) do
@@ -715,16 +492,16 @@ defmodule EExTest do
 
   describe "custom engines" do
     test "text" do
-      assert_eval("BODY(INIT:TEXT-1-1(foo))", "foo", [], engine: TestEngine)
+      assert_eval("BODY(INIT:TEXT(foo))", "foo", [], engine: TestEngine)
     end
 
     test "custom marker" do
-      assert_eval("BODY(INIT:TEXT-1-1(foo):DIV(:bar))", "foo <%/ :bar %>", [], engine: TestEngine)
+      assert_eval("BODY(INIT:TEXT(foo):DIV(:bar))", "foo <%/ :bar %>", [], engine: TestEngine)
     end
 
     test "begin/end" do
       assert_eval(
-        ~s[BODY(INIT:TEXT-1-1(foo):EQUAL(if do\n  "BEGIN:TEXT-1-17(this):END"\nelse\n  "BEGIN:TEXT-1-31(that):END"\nend))],
+        ~s[BODY(INIT:TEXT(foo):EQUAL(if() do\n  "BEGIN:TEXT(this):END"\nelse\n  "BEGIN:TEXT(that):END"\nend))],
         "foo <%= if do %>this<% else %>that<% end %>",
         [],
         engine: TestEngine
@@ -741,18 +518,8 @@ defmodule EExTest do
     end
   end
 
-  describe "parser options" do
-    test "customizes parsed code" do
-      atoms_encoder = fn "not_jose", _ -> {:ok, :jose} end
-
-      assert_eval("valid", "<%= not_jose %>", [jose: "valid"],
-        parser_options: [static_atoms_encoder: atoms_encoder]
-      )
-    end
-  end
-
   defp assert_eval(expected, actual, binding \\ [], opts \\ []) do
-    opts = Keyword.merge([file: __ENV__.file, engine: opts[:engine] || EEx.Engine], opts)
+    opts = Enum.into([file: __ENV__.file, engine: opts[:engine] || EEx.Engine], opts)
     result = EEx.eval_string(actual, binding, opts)
     assert result == expected
   end
@@ -760,27 +527,4 @@ defmodule EExTest do
   defp assert_normalized_newline_equal(expected, actual) do
     assert String.replace(expected, "\r\n", "\n") == String.replace(actual, "\r\n", "\n")
   end
-
-  def tuple_map({list, callback}) do
-    Enum.map(list, callback)
-  end
-
-  def switching_map(list, a, b) do
-    list
-    |> Enum.with_index()
-    |> Enum.map(fn
-      {element, index} when rem(index, 2) == 0 -> a.(element)
-      {element, index} when rem(index, 2) == 1 -> b.(element)
-    end)
-  end
-
-  defmacro switching_macro(list, a, do: block) do
-    quote do
-      b = fn var!(x) ->
-        unquote(block)
-      end
-
-      unquote(__MODULE__).switching_map(unquote(list), unquote(a), b)
-    end
-  end
 end

lib/eex/test/fixtures/eex_template_with_syntax_error.eex

@@ -1 +0,0 @@
-foo <%= bar

lib/eex/test/test_helper.exs

@@ -1,8 +1 @@
-{line_exclude, line_include} =
-  if line = System.get_env("LINE"), do: {[:test], [line: line]}, else: {[], []}
-
-ExUnit.start(
-  trace: !!System.get_env("TRACE"),
-  include: line_include,
-  exclude: line_exclude
-)
+ExUnit.start(trace: "--trace" in System.argv())

lib/elixir/Emakefile

@@ -8,9 +8,12 @@
   warn_unused_record,
   warn_deprecated_function,
   warn_obsolete_guard,
+  strict_validation,
   warn_exported_vars,
+  %% warn_export_vars,
   %% warn_missing_spec,
   %% warn_untyped_record,
+  %% warnings_as_errors,
   debug_info,
   {outdir, "ebin/"}
 ]}.

lib/elixir/diff.exs

@@ -1,156 +0,0 @@
-defmodule Diff do
-  @moduledoc """
-  Utilities for comparing build artifacts.
-  """
-
-  @known_chunks ~w(
-    abstract_code
-    debug_info
-    attributes
-    compile_info
-    exports
-    labeled_exports
-    imports
-    indexed_imports
-    locals
-    labeled_locals
-    atoms
-  )a
-
-  @doc """
-  Compares the build artifacts of two build directories.
-  """
-  @spec compare_dirs(Path.t(), Path.t()) ::
-          {
-            only1_paths :: list(Path.t()),
-            only2_paths :: list(Path.t()),
-            diff :: list({Path.t(), diff :: String.t()})
-          }
-  def compare_dirs(dir1, dir2) do
-    dir1 = Path.expand(dir1)
-    dir2 = Path.expand(dir2)
-
-    assert_dir!(dir1)
-    assert_dir!(dir2)
-
-    dir1_paths = relative_paths(dir1)
-    dir2_paths = relative_paths(dir2)
-
-    only1_paths = dir1_paths -- dir2_paths
-    only2_paths = dir2_paths -- dir1_paths
-    common_paths = dir1_paths -- only1_paths
-    common_files = Enum.reject(common_paths, &File.dir?/1)
-
-    diff =
-      Enum.flat_map(common_files, fn path ->
-        file1 = Path.join(dir1, path)
-        file2 = Path.join(dir2, path)
-
-        case compare_files(file1, file2) do
-          :eq -> []
-          {:diff, diff} -> [{path, diff}]
-        end
-      end)
-
-    {only1_paths, only2_paths, diff}
-  end
-
-  @doc """
-  Compares the contents of two files.
-
-  If the files are BEAM files, it performs a more human-friendly
-  "BEAM-diff".
-  """
-  @spec compare_files(Path.t(), Path.t()) :: :eq | {:diff, diff :: String.t()}
-  def compare_files(file1, file2) do
-    content1 = File.read!(file1)
-    content2 = File.read!(file2)
-
-    if content1 == content2 do
-      :eq
-    else
-      diff =
-        if String.ends_with?(file1, ".beam") do
-          beam_diff(file1, content1, file2, content2)
-        else
-          file_diff(file1, file2)
-        end
-
-      {:diff, diff}
-    end
-  end
-
-  defp beam_diff(file1, content1, file2, content2) do
-    with {:ok, {module, chunks1}} <- :beam_lib.chunks(content1, @known_chunks),
-         {:ok, {^module, chunks2}} <- :beam_lib.chunks(content2, @known_chunks),
-         true <- chunks1 != chunks2 do
-      for {chunk1, chunk2} <- Enum.zip(chunks1, chunks2), chunk1 != chunk2 do
-        tmp_file1 =
-          chunk1
-          |> inspect(pretty: true, limit: :infinity)
-          |> write_tmp()
-
-        tmp_file2 =
-          chunk2
-          |> inspect(pretty: true, limit: :infinity)
-          |> write_tmp()
-
-        file_diff(tmp_file1, tmp_file2)
-      end
-    else
-      _ ->
-        file_diff(file1, file2)
-    end
-  end
-
-  defp file_diff(file1, file2) do
-    {diff, _} = System.cmd("diff", [file1, file2])
-    diff
-  end
-
-  defp relative_paths(dir) do
-    dir
-    |> Path.join("**")
-    |> Path.wildcard()
-    |> Enum.map(&Path.relative_to(&1, dir))
-  end
-
-  defp assert_dir!(dir) do
-    unless File.dir?(dir) do
-      raise ArgumentError, "#{inspect(dir)} is not a directory"
-    end
-  end
-
-  defp write_tmp(content) do
-    filename = generate_tmp_filename()
-    File.mkdir_p!("tmp")
-    File.write!(Path.join("tmp", filename), content)
-    Path.join("tmp", filename)
-  end
-
-  defp generate_tmp_filename do
-    sec = :os.system_time(:second)
-    rand = :rand.uniform(999_999_999)
-    scheduler_id = :erlang.system_info(:scheduler_id)
-    "tmp-#{sec}-#{rand}-#{scheduler_id}"
-  end
-end
-
-case System.argv() do
-  [dir1, dir2] ->
-    case Diff.compare_dirs(dir1, dir2) do
-      {[], [], []} ->
-        IO.puts("#{inspect(dir1)} and #{inspect(dir2)} are equal")
-
-      {only1, only2, diff} ->
-        for path <- only1, do: IO.puts("Only in #{dir1}: #{path}")
-        for path <- only2, do: IO.puts("Only in #{dir2}: #{path}")
-        for {path, diff} <- diff, do: IO.puts("Diff #{path}:\n#{diff}")
-
-        System.halt(1)
-    end
-
-  _ ->
-    IO.puts("Please, provide two directories as arguments")
-    System.halt(1)
-end

lib/elixir/docs.exs

@@ -1,20 +1,6 @@
 # Returns config for Elixir docs
-
-canonical = System.fetch_env!("CANONICAL")
-
 [
-  extras: Path.wildcard("lib/elixir/pages/*.md") ++ ["CHANGELOG.md"],
-  deps: [
-    eex: "https://hexdocs.pm/eex/#{canonical}",
-    ex_unit: "https://hexdocs.pm/ex_unit/#{canonical}",
-    iex: "https://hexdocs.pm/iex/#{canonical}",
-    logger: "https://hexdocs.pm/logger/#{canonical}",
-    mix: "https://hexdocs.pm/mix/#{canonical}"
-  ],
-  groups_for_functions: [
-    Guards: &(&1[:guard] == true)
-  ],
-  skip_undefined_reference_warnings_on: ["lib/elixir/pages/compatibility-and-deprecations.md"],
+  extras: Path.wildcard("lib/elixir/pages/*.md"),
   groups_for_modules: [
     # [Kernel, Kernel.SpecialForms],
 
@@ -22,13 +8,14 @@ canonical = System.fetch_env!("CANONICAL")
       Atom,
       Base,
       Bitwise,
+      Calendar,
+      Calendar.ISO,
       Date,
       DateTime,
       Exception,
       Float,
       Function,
       Integer,
-      Module,
       NaiveDateTime,
       Record,
       Regex,
@@ -36,8 +23,7 @@ canonical = System.fetch_env!("CANONICAL")
       Time,
       Tuple,
       URI,
-      Version,
-      Version.Requirement
+      Version
     ],
     "Collections & Enumerables": [
       Access,
@@ -63,22 +49,19 @@ canonical = System.fetch_env!("CANONICAL")
       StringIO,
       System
     ],
-    Calendar: [
-      Calendar,
-      Calendar.ISO,
-      Calendar.TimeZoneDatabase,
-      Calendar.UTCOnlyTimeZoneDatabase
+    "Modules & Code": [
+      Code,
+      Kernel.ParallelCompiler,
+      Macro,
+      Macro.Env,
+      Module
     ],
     "Processes & Applications": [
       Agent,
       Application,
-      Config,
-      Config.Provider,
-      Config.Reader,
       DynamicSupervisor,
       GenServer,
       Node,
-      PartitionSupervisor,
       Process,
       Registry,
       Supervisor,
@@ -95,24 +78,14 @@ canonical = System.fetch_env!("CANONICAL")
       Protocol,
       String.Chars
     ],
-    "Code & Macros": [
-      Code,
-      Code.Fragment,
-      Kernel.ParallelCompiler,
-      Macro,
-      Macro.Env
+    Deprecated: [
+      Behaviour,
+      Dict,
+      GenEvent,
+      HashDict,
+      HashSet,
+      Set,
+      Supervisor.Spec
     ]
-
-    ## Automatically detected groups
-
-    # Deprecated: [
-    #   Behaviour,
-    #   Dict,
-    #   GenEvent,
-    #   HashDict,
-    #   HashSet,
-    #   Set,
-    #   Supervisor.Spec
-    # ]
   ]
 ]

lib/elixir/generate_app.escript

@@ -10,4 +10,4 @@ main([Source, Target, Version]) ->
   Props = lists:keyreplace(vsn, 1, Props1, {vsn, Version}),
   AppDef = io_lib:format("~tp.~n", [{application, Name, Props}]),
   ok = file:write_file(Target, AppDef),
-  io:format("Generated ~ts app~n", [Name]).
+  io:format("Generated ~ts.app~n", [Name]).

lib/elixir/lib/access.ex

@@ -2,12 +2,46 @@ defmodule Access do
   @moduledoc """
   Key-based access to data structures.
 
-  The `Access` module defines a behaviour for dynamically accessing
-  keys of any type in a data structure via the `data[key]` syntax.
+  Elixir supports three main key-value constructs: keywords,
+  maps, and structs. It also supports two mechanisms to access those keys:
+  by brackets (via `data[key]`) and by dot-syntax (via `data.field`).
 
-  `Access` supports keyword lists (`Keyword`) and maps (`Map`) out
-  of the box. Keywords supports only atoms keys, keys for maps can
-  be of any type. Both return `nil` if the key does not exist:
+  In the next section we will briefly recap the key-value constructs and then
+  discuss the access mechanisms.
+
+  ## Key-value constructs
+
+  Elixir provides three main key-value constructs, summarized below:
+
+    * keyword lists - they are lists of two-element tuples where
+      the first element is an atom. Commonly written in the
+      `[key: value]` syntax, they support only atom keys. Keyword
+      lists are used almost exclusively to pass options to functions
+      and macros. They keep the user ordering and allow duplicate
+      keys. See the `Keyword` module.
+
+    * maps - they are the "go to" key-value data structure in Elixir.
+      They are capable of supporting billions of keys of any type. They are
+      written using the `%{key => value}` syntax and also support the
+      `%{key: value}` syntax when the keys are atoms. They do not
+      have any specified ordering and do not allow duplicate keys.
+      See the `Map` module.
+
+    * structs - they are named maps with a pre-determined set of keys.
+      They are defined with `defstruct/1` and written using the
+      `%StructName{key: value}` syntax.
+
+  ## Key-based accessors
+
+  Elixir provides two mechanisms to access data structures by key,
+  described next.
+
+  ### Bracket-based access
+
+  The `data[key]` syntax is used to access data structures with a
+  dynamic number of keys, such as keywords and maps. The key can
+  be of any type. The bracket-based access syntax returns `nil`
+  if the key does not exist:
 
       iex> keywords = [a: 1, b: 2]
       iex> keywords[:a]
@@ -25,88 +59,108 @@ defmodule Access do
 
   This syntax is very convenient as it can be nested arbitrarily:
 
-      iex> keywords = [a: 1, b: 2]
-      iex> keywords[:c][:unknown]
-      nil
-
-  This works because accessing anything on a `nil` value, returns
-  `nil` itself:
-
-      iex> nil[:a]
-      nil
-
-  The access syntax can also be used with the `Kernel.put_in/2`,
-  `Kernel.update_in/2` and `Kernel.get_and_update_in/2` macros
-  to allow values to be set in nested data structures:
-
       iex> users = %{"john" => %{age: 27}, "meg" => %{age: 23}}
       iex> put_in(users["john"][:age], 28)
       %{"john" => %{age: 28}, "meg" => %{age: 23}}
 
-  > Attention! While the access syntax is allowed in maps via
-  > `map[key]`, if your map is made of predefined atom keys,
-  > you should prefer to access those atom keys with `map.key`
-  > instead of `map[key]`, as `map.key` will raise if the key
-  > is missing (which is not supposed to happen if the keys are
-  > predefined). Similarly, since structs are maps and structs
-  > have predefined keys, they only allow the `struct.key`
-  > syntax and they do not allow the `struct[key]` access syntax.
-  > See the `Map` module for more information.
+  Furthermore, the bracket-based access syntax transparently ignores
+  `nil` values. When trying to access anything on a `nil` value, `nil`
+  is returned:
+
+      iex> keywords = [a: 1, b: 2]
+      iex> keywords[:c][:unknown]
+      nil
+
+      iex> nil[:a]
+      nil
+
+  Internally, `data[key]` translates  to `Access.get(term, key, nil)`.
+  Developers interested in implementing their own key-value data
+  structures can implement the `Access` behaviour to provide the
+  bracket-based access syntax. `Access` requires the key comparison
+  to be implemented using the `===/2` operator.
+
+  ### Dot-based syntax
+
+  The `data.field` syntax is used exclusively to access atom fields
+  in maps and structs. If the accessed field does not exist, an error is
+  raised. This is a deliberate decision: since all of the
+  fields in a struct are pre-determined, structs support only the
+  dot-based syntax and not the access one.
+
+  Imagine a struct named `User` with a `:name` field. The following would raise:
+
+      user = %User{name: "John"}
+      user[:name]
+      # ** (UndefinedFunctionError) undefined function User.fetch/2 (User does not implement the Access behaviour)
+
+  Instead we should use the `user.name` syntax to access fields:
+
+      user.name
+      #=> "John"
+
+  Differently from `user[:name]`, `user.name` is not extensible via
+  a behaviour and is restricted only to structs and atom keys in maps.
+
+  ### Summing up
+
+  The bracket-based syntax, `user[:name]`, is used by dynamic structures,
+  is extensible and returns nil on misisng keys.
+
+  The dot-based syntax, `user.name`, is used exclusively to access atom
+  keys in maps and structs, and it raises on missing keys.
 
   ## Nested data structures
 
   Both key-based access syntaxes can be used with the nested update
-  functions and macros in `Kernel`, such as `Kernel.get_in/2`,
-  `Kernel.put_in/3`, `Kernel.update_in/3`, `Kernel.pop_in/2`, and
-  `Kernel.get_and_update_in/3`.
+  functions and macros in `Kernel`, such as `Kernel.get_in/2`, `Kernel.put_in/3`,
+  `Kernel.update_in/3`, `Kernel.pop_in/2`, and `Kernel.get_and_update_in/3`.
 
   For example, to update a map inside another map:
 
-      iex> users = %{"john" => %{age: 27}, "meg" => %{age: 23}}
-      iex> put_in(users["john"].age, 28)
-      %{"john" => %{age: 28}, "meg" => %{age: 23}}
+     iex> users = %{"john" => %{age: 27}, "meg" => %{age: 23}}
+     iex> put_in(users["john"].age, 28)
+     %{"john" => %{age: 28}, "meg" => %{age: 23}}
 
   This module provides convenience functions for traversing other
   structures, like tuples and lists. These functions can be used
   in all the `Access`-related functions and macros in `Kernel`.
 
-  For instance, given a user map with the `:name` and `:languages`
-  keys, here is how to deeply traverse the map and convert all
-  language names to uppercase:
+  For instance, given a user map with the `:name` and `:languages` keys,
+  here is how to deeply traverse the map and convert all language names
+  to uppercase:
 
       iex> languages = [
       ...>   %{name: "elixir", type: :functional},
-      ...>   %{name: "c", type: :procedural}
+      ...>   %{name: "c", type: :procedural},
       ...> ]
       iex> user = %{name: "john", languages: languages}
       iex> update_in(user, [:languages, Access.all(), :name], &String.upcase/1)
-      %{
-        name: "john",
-        languages: [
-          %{name: "ELIXIR", type: :functional},
-          %{name: "C", type: :procedural}
-        ]
-      }
+      %{name: "john",
+        languages: [%{name: "ELIXIR", type: :functional},
+                    %{name: "C", type: :procedural}]}
 
-  See the functions `key/1`, `key!/1`, `elem/1`, and `all/0` for
-  some of the available accessors.
+  See the functions `key/1`, `key!/1`, `elem/1`, and `all/0` for some of the
+  available accessors.
   """
 
   @type container :: keyword | struct | map
   @type nil_container :: nil
-  @type t :: container | nil_container | any
+  @type any_container :: any
+  @type t :: container | nil_container | any_container
   @type key :: any
   @type value :: any
 
-  @type get_fun(data) ::
-          (:get, data, (term -> term) -> new_data :: container)
+  @type get_fun(data, get_value) ::
+          (:get, data, (term -> term) ->
+             {get_value, new_data :: container})
 
-  @type get_and_update_fun(data, current_value) ::
+  @type get_and_update_fun(data, get_value) ::
           (:get_and_update, data, (term -> term) ->
-             {current_value, new_data :: container} | :pop)
+             {get_value, new_data :: container} | :pop)
 
-  @type access_fun(data, current_value) ::
-          get_fun(data) | get_and_update_fun(data, current_value)
+  @type access_fun(data, get_value) ::
+          get_fun(data, get_value) | get_and_update_fun(data, get_value)
 
   @doc """
   Invoked in order to access the value stored under `key` in the given term `term`.
@@ -132,16 +186,16 @@ defmodule Access do
 
   The implementation of this callback should invoke `fun` with the value under
   `key` in the passed structure `data`, or with `nil` if `key` is not present in it.
-  This function must return either `{current_value, new_value}` or `:pop`.
+  This function must return either `{get_value, update_value}` or `:pop`.
 
-  If the passed function returns `{current_value, new_value}`,
-  the return value of this callback should be `{current_value, new_data}`, where:
+  If the passed function returns `{get_value, update_value}`,
+  the return value of this callback should be `{get_value, new_data}`, where:
 
-    * `current_value` is the retrieved value (which can be operated on before being returned)
+    * `get_value` is the retrieved value (which can be operated on before being returned)
 
-    * `new_value` is the new value to be stored under `key`
+    * `update_value` is the new value to be stored under `key`
 
-    * `new_data` is `data` after updating the value of `key` with `new_value`.
+    * `new_data` is `data` after updating the value of `key` with `update_value`.
 
   If the passed function returns `:pop`, the return value of this callback
   must be `{value, new_data}` where `value` is the value under `key`
@@ -150,9 +204,8 @@ defmodule Access do
   See the implementations of `Map.get_and_update/3` or `Keyword.get_and_update/3`
   for more examples.
   """
-  @callback get_and_update(data, key, (value | nil -> {current_value, new_value :: value} | :pop)) ::
-              {current_value, new_data :: data}
-            when current_value: value, data: container
+  @callback get_and_update(data, key, (value -> {get_value, value} | :pop)) :: {get_value, data}
+            when get_value: var, data: container | any_container
 
   @doc """
   Invoked to "pop" the value under `key` out of the given data structure.
@@ -166,18 +219,14 @@ defmodule Access do
 
   See the implementations for `Map.pop/3` or `Keyword.pop/3` for more examples.
   """
-  @callback pop(data, key) :: {value, data} when data: container
+  @callback pop(data, key) :: {value, data} when data: container | any_container
 
   defmacrop raise_undefined_behaviour(exception, module, top) do
     quote do
       exception =
         case __STACKTRACE__ do
           [unquote(top) | _] ->
-            reason =
-              "#{inspect(unquote(module))} does not implement the Access behaviour. " <>
-                "If you are using get_in/put_in/update_in, you can specify the field " <>
-                "to be accessed using Access.key!/1"
-
+            reason = "#{inspect(unquote(module))} does not implement the Access behaviour"
             %{unquote(exception) | reason: reason}
 
           _ ->
@@ -238,25 +287,6 @@ defmodule Access do
     :error
   end
 
-  @doc """
-  Same as `fetch/2` but returns the value directly,
-  or raises a `KeyError` exception if `key` is not found.
-
-  ## Examples
-
-      iex> Access.fetch!(%{name: "meg", age: 26}, :name)
-      "meg"
-
-  """
-  @doc since: "1.10.0"
-  @spec fetch!(container, term) :: term
-  def fetch!(container, key) do
-    case fetch(container, key) do
-      {:ok, value} -> value
-      :error -> raise(KeyError, key: key, term: container)
-    end
-  end
-
   @doc """
   Gets the value for the given key in a container (a map, keyword
   list, or struct that implements the `Access` behaviour).
@@ -323,26 +353,17 @@ defmodule Access do
   a struct that implements the `Access` behaviour).
 
   The `fun` argument receives the value of `key` (or `nil` if `key` is not
-  present in `container`) and must return a two-element tuple `{current_value, new_value}`:
-  the "get" value `current_value` (the retrieved value, which can be operated on before
-  being returned) and the new value to be stored under `key` (`new_value`).
+  present in `container`) and must return a two-element tuple `{get_value, update_value}`:
+  the "get" value `get_value` (the retrieved value, which can be operated on before
+  being returned) and the new value to be stored under `key` (`update_value`).
   `fun` may also return `:pop`, which means the current value
   should be removed from the container and returned.
 
   The returned value is a two-element tuple with the "get" value returned by
   `fun` and a new container with the updated value under `key`.
-
-  ## Examples
-
-      iex> Access.get_and_update([a: 1], :a, fn current_value ->
-      ...>   {current_value, current_value + 1}
-      ...> end)
-      {1, [a: 2]}
-
   """
-  @spec get_and_update(data, key, (value | nil -> {current_value, new_value :: value} | :pop)) ::
-          {current_value, new_data :: data}
-        when current_value: var, data: container
+  @spec get_and_update(data, key, (value -> {get_value, value} | :pop)) :: {get_value, data}
+        when get_value: var, data: container
   def get_and_update(container, key, fun)
 
   def get_and_update(%module{} = container, key, fun) do
@@ -425,7 +446,7 @@ defmodule Access do
   The returned function uses the default value if the key does not exist.
   This can be used to specify defaults and safely traverse missing keys:
 
-      iex> get_in(%{}, [Access.key(:user, %{}), Access.key(:name, "meg")])
+      iex> get_in(%{}, [Access.key(:user, %{name: "meg"}), Access.key(:name)])
       "meg"
 
   Such is also useful when using update functions, allowing us to introduce
@@ -448,11 +469,14 @@ defmodule Access do
 
   An error is raised if the accessed structure is not a map or a struct:
 
+      iex> get_in(nil, [Access.key(:foo)])
+      ** (BadMapError) expected a map, got: nil
+
       iex> get_in([], [Access.key(:foo)])
       ** (BadMapError) expected a map, got: []
 
   """
-  @spec key(key, term) :: access_fun(data :: struct | map, current_value :: term)
+  @spec key(key, term) :: access_fun(data :: struct | map, get_value :: term)
   def key(key, default \\ nil) do
     fn
       :get, data, next ->
@@ -496,7 +520,7 @@ defmodule Access do
       ** (RuntimeError) Access.key!/1 expected a map/struct, got: []
 
   """
-  @spec key!(key) :: access_fun(data :: struct | map, current_value :: term)
+  @spec key!(key) :: access_fun(data :: struct | map, get_value :: term)
   def key!(key) do
     fn
       :get, %{} = data, next ->
@@ -544,7 +568,7 @@ defmodule Access do
       ** (RuntimeError) Access.elem/1 expected a tuple, got: %{}
 
   """
-  @spec elem(non_neg_integer) :: access_fun(data :: tuple, current_value :: term)
+  @spec elem(non_neg_integer) :: access_fun(data :: tuple, get_value :: term)
   def elem(index) when is_integer(index) and index >= 0 do
     pos = index + 1
 
@@ -587,7 +611,7 @@ defmodule Access do
   numbers and multiplying odd numbers by 2:
 
       iex> require Integer
-      iex> get_and_update_in([1, 2, 3, 4, 5], [Access.all()], fn num ->
+      iex> get_and_update_in([1, 2, 3, 4, 5], [Access.all], fn num ->
       ...>   if Integer.is_even(num), do: :pop, else: {num, num * 2}
       ...> end)
       {[1, 2, 3, 4, 5], [2, 6, 10]}
@@ -598,7 +622,7 @@ defmodule Access do
       ** (RuntimeError) Access.all/0 expected a list, got: %{}
 
   """
-  @spec all() :: access_fun(data :: list, current_value :: list)
+  @spec all() :: access_fun(data :: list, get_value :: list)
   def all() do
     &all/3
   end
@@ -637,16 +661,10 @@ defmodule Access do
       iex> list = [%{name: "john"}, %{name: "mary"}]
       iex> get_in(list, [Access.at(1), :name])
       "mary"
-      iex> get_in(list, [Access.at(-1), :name])
-      "mary"
       iex> get_and_update_in(list, [Access.at(0), :name], fn prev ->
       ...>   {prev, String.upcase(prev)}
       ...> end)
       {"john", [%{name: "JOHN"}, %{name: "mary"}]}
-      iex> get_and_update_in(list, [Access.at(-1), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {"mary", [%{name: "john"}, %{name: "MARY"}]}
 
   `at/1` can also be used to pop elements out of a list or
   a key inside of a list:
@@ -667,14 +685,19 @@ defmodule Access do
       ...> end)
       {nil, [%{name: "john"}, %{name: "mary"}]}
 
+  An error is raised for negative indexes:
+
+      iex> get_in([], [Access.at(-1)])
+      ** (FunctionClauseError) no function clause matching in Access.at/1
+
   An error is raised if the accessed structure is not a list:
 
       iex> get_in(%{}, [Access.at(1)])
       ** (RuntimeError) Access.at/1 expected a list, got: %{}
 
   """
-  @spec at(integer) :: access_fun(data :: list, current_value :: term)
-  def at(index) when is_integer(index) do
+  @spec at(non_neg_integer) :: access_fun(data :: list, get_value :: term)
+  def at(index) when is_integer(index) and index >= 0 do
     fn op, data, next -> at(op, data, index, next) end
   end
 
@@ -683,69 +706,26 @@ defmodule Access do
   end
 
   defp at(:get_and_update, data, index, next) when is_list(data) do
-    get_and_update_at(data, index, next, [], fn -> nil end)
+    get_and_update_at(data, index, next, [])
   end
 
   defp at(_op, data, _index, _next) do
     raise "Access.at/1 expected a list, got: #{inspect(data)}"
   end
 
-  defp get_and_update_at([head | rest], 0, next, updates, _default_fun) do
+  defp get_and_update_at([head | rest], 0, next, updates) do
     case next.(head) do
       {get, update} -> {get, :lists.reverse([update | updates], rest)}
       :pop -> {head, :lists.reverse(updates, rest)}
     end
   end
 
-  defp get_and_update_at([_ | _] = list, index, next, updates, default_fun) when index < 0 do
-    list_length = length(list)
-
-    if list_length + index >= 0 do
-      get_and_update_at(list, list_length + index, next, updates, default_fun)
-    else
-      {default_fun.(), list}
-    end
+  defp get_and_update_at([head | rest], index, next, updates) do
+    get_and_update_at(rest, index - 1, next, [head | updates])
   end
 
-  defp get_and_update_at([head | rest], index, next, updates, default_fun) when index > 0 do
-    get_and_update_at(rest, index - 1, next, [head | updates], default_fun)
-  end
-
-  defp get_and_update_at([], _index, _next, updates, default_fun) do
-    {default_fun.(), :lists.reverse(updates)}
-  end
-
-  @doc ~S"""
-  Same as `at/1` except that it raises `Enum.OutOfBoundsError`
-  if the given index is out of bounds.
-
-  ## Examples
-
-      iex> get_in([:a, :b, :c], [Access.at!(2)])
-      :c
-      iex> get_in([:a, :b, :c], [Access.at!(3)])
-      ** (Enum.OutOfBoundsError) out of bounds error
-
-  """
-  @doc since: "1.11.0"
-  @spec at!(integer) :: access_fun(data :: list, current_value :: term)
-  def at!(index) when is_integer(index) do
-    fn op, data, next -> at!(op, data, index, next) end
-  end
-
-  defp at!(:get, data, index, next) when is_list(data) do
-    case Enum.fetch(data, index) do
-      {:ok, value} -> next.(value)
-      :error -> raise Enum.OutOfBoundsError
-    end
-  end
-
-  defp at!(:get_and_update, data, index, next) when is_list(data) do
-    get_and_update_at(data, index, next, [], fn -> raise Enum.OutOfBoundsError end)
-  end
-
-  defp at!(_op, data, _index, _next) do
-    raise "Access.at!/1 expected a list, got: #{inspect(data)}"
+  defp get_and_update_at([], _index, _next, updates) do
+    {nil, :lists.reverse(updates)}
   end
 
   @doc ~S"""
@@ -795,7 +775,7 @@ defmodule Access do
 
   """
   @doc since: "1.6.0"
-  @spec filter((term -> boolean)) :: access_fun(data :: list, current_value :: list)
+  @spec filter((term -> boolean)) :: access_fun(data :: list, get_value :: list)
   def filter(func) when is_function(func) do
     fn op, data, next -> filter(op, data, func, next) end
   end
@@ -829,118 +809,4 @@ defmodule Access do
   defp get_and_update_filter([], _func, _next, updates, gets) do
     {:lists.reverse(gets), :lists.reverse(updates)}
   end
-
-  @doc ~S"""
-  Returns a function that accesses all items of a list that are within the provided range.
-
-  The range will be normalized following the same rules from `Enum.slice/2`.
-
-  The returned function is typically passed as an accessor to `Kernel.get_in/2`,
-  `Kernel.get_and_update_in/3`, and friends.
-
-  ## Examples
-
-      iex> list = [%{name: "john", salary: 10}, %{name: "francine", salary: 30}, %{name: "vitor", salary: 25}]
-      iex> get_in(list, [Access.slice(1..2), :name])
-      ["francine", "vitor"]
-      iex> get_and_update_in(list, [Access.slice(1..3//2), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {["francine"], [%{name: "john", salary: 10}, %{name: "FRANCINE", salary: 30}, %{name: "vitor", salary: 25}]}
-
-  `slice/1` can also be used to pop elements out of a list or
-  a key inside of a list:
-
-      iex> list = [%{name: "john", salary: 10}, %{name: "francine", salary: 30}, %{name: "vitor", salary: 25}]
-      iex> pop_in(list, [Access.slice(-2..-1)])
-      {[%{name: "francine", salary: 30}, %{name: "vitor", salary: 25}], [%{name: "john", salary: 10}]}
-      iex> pop_in(list, [Access.slice(-2..-1), :name])
-      {["francine", "vitor"], [%{name: "john", salary: 10}, %{salary: 30}, %{salary: 25}]}
-
-  When no match is found, an empty list is returned and the update function is never called
-
-      iex> list = [%{name: "john", salary: 10}, %{name: "francine", salary: 30}, %{name: "vitor", salary: 25}]
-      iex> get_in(list, [Access.slice(5..10//2), :name])
-      []
-      iex> get_and_update_in(list, [Access.slice(5..10//2), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {[], [%{name: "john", salary: 10}, %{name: "francine", salary: 30}, %{name: "vitor", salary: 25}]}
-
-  An error is raised if the accessed structure is not a list:
-
-      iex> get_in(%{}, [Access.slice(2..10//3)])
-      ** (ArgumentError) Access.slice/1 expected a list, got: %{}
-
-  An error is raised if the step of the range is negative:
-
-      iex> get_in([], [Access.slice(2..10//-1)])
-      ** (ArgumentError) Access.slice/1 does not accept ranges with negative steps, got: 2..10//-1
-
-  """
-  @doc since: "1.14"
-  @spec slice(Range.t()) :: access_fun(data :: list, current_value :: list)
-  def slice(%Range{} = range) do
-    if range.step > 0 do
-      fn op, data, next -> slice(op, data, range, next) end
-    else
-      raise ArgumentError,
-            "Access.slice/1 does not accept ranges with negative steps, got: #{inspect(range)}"
-    end
-  end
-
-  defp slice(:get, data, %Range{} = range, next) when is_list(data) do
-    data
-    |> Enum.slice(range)
-    |> Enum.map(next)
-  end
-
-  defp slice(:get_and_update, data, range, next) when is_list(data) do
-    range = normalize_range(range, data)
-
-    if range.first > range.last do
-      {[], data}
-    else
-      get_and_update_slice(data, range, next, [], [], 0)
-    end
-  end
-
-  defp slice(_op, data, _range, _next) do
-    raise ArgumentError, "Access.slice/1 expected a list, got: #{inspect(data)}"
-  end
-
-  defp normalize_range(%Range{first: first, last: last, step: step}, list)
-       when first < 0 or last < 0 do
-    count = length(list)
-    first = if first >= 0, do: first, else: Kernel.max(first + count, 0)
-    last = if last >= 0, do: last, else: last + count
-    Range.new(first, last, step)
-  end
-
-  defp normalize_range(range, _list), do: range
-
-  defp get_and_update_slice([head | rest], range, next, updates, gets, index) do
-    if index in range do
-      case next.(head) do
-        :pop ->
-          get_and_update_slice(rest, range, next, updates, [head | gets], index + 1)
-
-        {get, update} ->
-          get_and_update_slice(
-            rest,
-            range,
-            next,
-            [update | updates],
-            [get | gets],
-            index + 1
-          )
-      end
-    else
-      get_and_update_slice(rest, range, next, [head | updates], gets, index + 1)
-    end
-  end
-
-  defp get_and_update_slice([], _range, _next, updates, gets, _index) do
-    {:lists.reverse(gets), :lists.reverse(updates)}
-  end
 end

lib/elixir/lib/agent.ex

@@ -11,50 +11,44 @@ defmodule Agent do
 
   ## Examples
 
-  For example, the following agent implements a counter:
+  For example, in the Mix tool that ships with Elixir, we need
+  to keep a set of all tasks executed by a given project. Since
+  this set is shared, we can implement it with an agent:
 
-      defmodule Counter do
+      defmodule Mix.TasksServer do
         use Agent
 
-        def start_link(initial_value) do
-          Agent.start_link(fn -> initial_value end, name: __MODULE__)
+        def start_link(_) do
+          Agent.start_link(fn -> MapSet.new end, name: __MODULE__)
         end
 
-        def value do
-          Agent.get(__MODULE__, & &1)
+        @doc "Checks if the task has already executed"
+        def executed?(task, project) do
+          item = {task, project}
+          Agent.get(__MODULE__, fn set ->
+            item in set
+          end)
         end
 
-        def increment do
-          Agent.update(__MODULE__, &(&1 + 1))
+        @doc "Marks a task as executed"
+        def put_task(task, project) do
+          item = {task, project}
+          Agent.update(__MODULE__, &MapSet.put(&1, item))
+        end
+
+        @doc "Resets the executed tasks and returns the previous list of tasks"
+        def take_all() do
+          Agent.get_and_update(__MODULE__, fn set ->
+            {Enum.into(set, []), MapSet.new}
+          end)
         end
       end
 
-  Usage would be:
-
-      Counter.start_link(0)
-      #=> {:ok, #PID<0.123.0>}
-
-      Counter.value()
-      #=> 0
-
-      Counter.increment()
-      #=> :ok
-
-      Counter.increment()
-      #=> :ok
-
-      Counter.value()
-      #=> 2
-
-  Thanks to the agent server process, the counter can be safely incremented
-  concurrently.
-
-  Agents provide a segregation between the client and server APIs (similar to
-  `GenServer`s). In particular, the functions passed as arguments to the calls to
-  `Agent` functions are invoked inside the agent (the server). This distinction
-  is important because you may want to avoid expensive operations inside the
-  agent, as they will effectively block the agent until the request is
-  fulfilled.
+  Agents provide a segregation between the client and server APIs (similar
+  to GenServers). In particular, the anonymous functions given to the `Agent`
+  are executed inside the agent (the server). This distinction is important
+  because you may want to avoid expensive operations inside the agent,
+  as they will effectively block the agent until the request is fulfilled.
 
   Consider these two examples:
 
@@ -65,7 +59,7 @@ defmodule Agent do
 
       # Compute in the agent/client
       def get_something(agent) do
-        Agent.get(agent, & &1) |> do_something_expensive()
+        Agent.get(agent, &(&1)) |> do_something_expensive()
       end
 
   The first function blocks the agent. The second function copies all the state
@@ -79,60 +73,20 @@ defmodule Agent do
   than in the server can lead to race conditions if multiple clients are trying
   to update the same state to different values.
 
-  ## How to supervise
-
-  An `Agent` is most commonly started under a supervision tree.
-  When we invoke `use Agent`, it automatically defines a `child_spec/1`
-  function that allows us to start the agent directly under a supervisor.
-  To start an agent under a supervisor with an initial counter of 0,
-  one may do:
-
-      children = [
-        {Counter, 0}
-      ]
-
-      Supervisor.start_link(children, strategy: :one_for_all)
-
-  While one could also simply pass the `Counter` as a child to the supervisor,
-  such as:
-
-      children = [
-        Counter # Same as {Counter, []}
-      ]
-
-      Supervisor.start_link(children, strategy: :one_for_all)
-
-  The definition above wouldn't work for this particular example,
-  as it would attempt to start the counter with an initial value
-  of an empty list. However, this may be a viable option in your
-  own agents. A common approach is to use a keyword list, as that
-  would allow setting the initial value and giving a name to the
-  counter process, for example:
-
-      def start_link(opts) do
-        {initial_value, opts} = Keyword.pop(opts, :initial_value, 0)
-        Agent.start_link(fn -> initial_value end, opts)
-      end
-
-  and then you can use `Counter`, `{Counter, name: :my_counter}` or
-  even `{Counter, initial_value: 0, name: :my_counter}` as a child
-  specification.
-
-  `use Agent` also accepts a list of options which configures the
-  child specification and therefore how it runs under a supervisor.
-  The generated `child_spec/1` can be customized with the following options:
+  Finally note `use Agent` defines a `child_spec/1` function, allowing the
+  defined module to be put under a supervision tree. The generated
+  `child_spec/1` can be customized with the following options:
 
     * `:id` - the child specification identifier, defaults to the current module
+    * `:start` - how to start the child process (defaults to calling `__MODULE__.start_link/1`)
     * `:restart` - when the child should be restarted, defaults to `:permanent`
-    * `:shutdown` - how to shut down the child, either immediately or by giving it time to shut down
+    * `:shutdown` - how to shut down the child
 
   For example:
 
       use Agent, restart: :transient, shutdown: 10_000
 
-  See the "Child specification" section in the `Supervisor` module for more
-  detailed information. The `@doc` annotation immediately preceding
-  `use Agent` will be attached to the generated `child_spec/1` function.
+  See the `Supervisor` docs for more information.
 
   ## Name registration
 
@@ -188,7 +142,7 @@ defmodule Agent do
   @doc """
   Returns a specification to start an agent under a supervisor.
 
-  See the "Child specification" section in the `Supervisor` module for more detailed information.
+  See `Supervisor`.
   """
   @doc since: "1.5.0"
   def child_spec(arg) do
@@ -201,14 +155,11 @@ defmodule Agent do
   @doc false
   defmacro __using__(opts) do
     quote location: :keep, bind_quoted: [opts: opts] do
-      unless Module.has_attribute?(__MODULE__, :doc) do
-        @doc """
-        Returns a specification to start this module under a supervisor.
-
-        See `Supervisor`.
-        """
-      end
+      @doc """
+      Returns a specification to start this module under a supervisor.
 
+      See `Supervisor`.
+      """
       def child_spec(arg) do
         default = %{
           id: __MODULE__,
@@ -227,9 +178,9 @@ defmodule Agent do
 
   This is often used to start the agent as part of a supervision tree.
 
-  Once the agent is spawned, the given function `fun` is invoked in the server
-  process, and should return the initial agent state. Note that `start_link/2`
-  does not return until the given function has returned.
+  Once the agent is spawned, the given function `fun` is invoked and its return
+  value is used as the agent state. Note that `start_link/2` does not return
+  until the given function has returned.
 
   ## Options
 
@@ -241,7 +192,7 @@ defmodule Agent do
   and the start function will return `{:error, :timeout}`.
 
   If the `:debug` option is present, the corresponding function in the
-  [`:sys` module](`:sys`) will be invoked.
+  [`:sys` module](http://www.erlang.org/doc/man/sys.html) will be invoked.
 
   If the `:spawn_opt` option is present, its value will be passed as options
   to the underlying process as in `Process.spawn/4`.
@@ -423,15 +374,6 @@ defmodule Agent do
   Same as `update/3` but a module, function, and arguments are expected
   instead of an anonymous function. The state is added as first
   argument to the given list of arguments.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.update(pid, Kernel, :+, [12])
-      :ok
-      iex> Agent.get(pid, fn state -> state end)
-      54
-
   """
   @spec update(agent, module, atom, [term], timeout) :: :ok
   def update(agent, module, fun, args, timeout \\ 5000) do
@@ -447,15 +389,6 @@ defmodule Agent do
 
   Note that `cast` returns `:ok` immediately, regardless of whether `agent` (or
   the node it should live on) exists.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.cast(pid, fn state -> state + 1 end)
-      :ok
-      iex> Agent.get(pid, fn state -> state end)
-      43
-
   """
   @spec cast(agent, (state -> state)) :: :ok
   def cast(agent, fun) when is_function(fun, 1) do
@@ -468,15 +401,6 @@ defmodule Agent do
   Same as `cast/2` but a module, function, and arguments are expected
   instead of an anonymous function. The state is added as first
   argument to the given list of arguments.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.cast(pid, Kernel, :+, [12])
-      :ok
-      iex> Agent.get(pid, fn state -> state end)
-      54
-
   """
   @spec cast(agent, module, atom, [term]) :: :ok
   def cast(agent, module, fun, args) do

lib/elixir/lib/application.ex

@@ -7,147 +7,79 @@ defmodule Application do
   programming languages, but with some additional characteristics.
 
   An application is a component implementing some specific functionality, with a
-  standardized directory structure, configuration, and life cycle. Applications
-  are *loaded*, *started*, and *stopped*. Each application also has its own
-  environment, which provides a unified API for configuring each application.
+  standardized directory structure, configuration, and lifecycle. Applications
+  are *loaded*, *started*, and *stopped*.
 
-  Developers typically interact with the application environment and its
-  callback module. Therefore those will be the topics we will cover first
-  before jumping into details about the application resource file and life-cycle.
+  ## The application resource file
+
+  Applications are specified in their [*resource
+  file*](http://erlang.org/doc/man/app.html), which is a file called `APP.app`,
+  where `APP` is the application name. For example, the application resource
+  file of the OTP application `ex_unit` is called `ex_unit.app`.
+
+  You'll find the resource file of an application in its `ebin` directory, it is
+  generated automatically by Mix. Some of its keys are taken from the keyword
+  lists returned by the `project/0` and `application/0` functions defined in
+  `mix.exs`, and others are generated by Mix itself.
+
+  You can learn more about the generation of application resource files in the
+  documentation of `Mix.Tasks.Compile.App`, available as well by running `mix
+  help compile.app`.
 
   ## The application environment
 
-  Each application has its own environment. The environment is a keyword list
-  that maps atoms to terms. Note that this environment is unrelated to the
-  operating system environment.
+  The key `env` of an application resource file has a list of tuples that map
+  atoms to terms, and its contents are known as the application *environment*.
+  Note that this environment is unrelated to the operating system environment.
 
   By default, the environment of an application is an empty list. In a Mix
-  project's `mix.exs` file, you can set the `:env` key in `application/0`:
+  project you can set that key in `application/0`:
 
       def application do
-        [env: [db_host: "localhost"]]
+        [env: [redis_host: "localhost"]]
       end
 
-  Now, in your application, you can read this environment by using functions
-  such as `fetch_env!/2` and friends:
+  and the generated application resource file is going to have it included.
 
-      defmodule MyApp.DBClient do
-        def start_link() do
-          SomeLib.DBClient.start_link(host: db_host())
-        end
+  The environment is available after loading the application, which is a process
+  explained later:
 
-        defp db_host do
-          Application.fetch_env!(:my_app, :db_host)
-        end
-      end
+      Application.load(:APP_NAME)
+      #=> :ok
+
+      Application.get_env(:APP_NAME, :redis_host)
+      #=> "localhost"
 
   In Mix projects, the environment of the application and its dependencies can
-  be overridden via the `config/config.exs` and `config/runtime.exs` files. The
-  former is loaded at build-time, before your code compiles, and the latter at
-  runtime, just before your app starts. For example, someone using your application
-  can override its `:db_host` environment variable as follows:
+  be overridden via the `config/config.exs` file. If you start the application
+  with Mix, that configuration is available at compile time, and at runtime too,
+  but take into account it is not included in the generated application resource
+  file, and it is not available if you start the application without Mix.
 
-      import Config
-      config :my_app, :db_host, "db.local"
+  For example, someone using your application can override its `:redis_host`
+  environment variable as follows:
 
-  See the "Configuration" section in the `Mix` module for more information.
-  You can also change the application environment dynamically by using functions
-  such as `put_env/3` and `delete_env/2`.
+      config :APP_NAME, redis_host: "redis.local"
 
-  > Note: The config files `config/config.exs` and `config/runtime.exs`
-  > are rarely used by libraries. Libraries typically define their environment
-  > in the `def application` function of their `mix.exs`. Configuration files
-  > are rather used by applications to configure their libraries.
+  The function `put_env/3` allows dynamic configuration of the application
+  environment, but as a rule of thumb each application is responsible for its
+  own environment. Please do not use the functions in this module for directly
+  accessing or modifying the environment of other applications.
 
-  > Note: Each application is responsible for its own environment. Do not
-  > use the functions in this module for directly accessing or modifying
-  > the environment of other applications. Whenever you change the application
-  > environment, Elixir's build tool will only recompile the files that
-  > belong to that application. So if you read the application environment
-  > of another application, there is a chance you will be depending on
-  > outdated configuration, as your file won't be recompiled as it changes.
-
-  ## Compile-time environment
-
-  In the previous example, we read the application environment at runtime:
-
-      defmodule MyApp.DBClient do
-        def start_link() do
-          SomeLib.DBClient.start_link(host: db_host())
-        end
-
-        defp db_host do
-          Application.fetch_env!(:my_app, :db_host)
-        end
-      end
-
-  In other words, the environment key `:db_host` for application `:my_app`
-  will only be read when `MyApp.DBClient` effectively starts. While reading
-  the application environment at runtime is the preferred approach, in some
-  rare occasions you may want to use the application environment to configure
-  the compilation of a certain project. However, if you try to access
-  `Application.fetch_env!/2` outside of a function:
-
-      defmodule MyApp.DBClient do
-        @db_host Application.fetch_env!(:my_app, :db_host)
-
-        def start_link() do
-          SomeLib.DBClient.start_link(host: @db_host)
-        end
-      end
-
-  You might see warnings and errors:
-
-      warning: Application.fetch_env!/2 is discouraged in the module body,
-      use Application.compile_env/3 instead
-        iex:3: MyApp.DBClient
-
-      ** (ArgumentError) could not fetch application environment :db_host
-      for application :my_app because the application was not loaded nor
-      configured
-
-  This happens because, when defining modules, the application environment
-  is not yet available. Luckily, the warning tells us how to solve this
-  issue, by using `Application.compile_env/3` instead:
-
-      defmodule MyApp.DBClient do
-        @db_host Application.compile_env(:my_app, :db_host, "db.local")
-
-        def start_link() do
-          SomeLib.DBClient.start_link(host: @db_host)
-        end
-      end
-
-  The difference here is that `compile_env` expects the default value to be
-  given as an argument, instead of using the `def application` function of
-  your `mix.exs`. Furthermore, by using `compile_env/3`, tools like Mix will
-  store the values used during compilation and compare the compilation values
-  with the runtime values whenever your system starts, raising an error in
-  case they differ.
-
-  In any case, compile-time environments should be avoided. Whenever possible,
-  reading the application environment at runtime should be the first choice.
+  The application environment can be overriden via the `-config` option of
+  `erl`, as well as command-line flags, as we are going to see below.
 
   ## The application callback module
 
-  Applications can be loaded, started, and stopped. Generally, build tools
-  like Mix take care of starting an application and all of its dependencies
-  for you, but you can also do it manually by calling:
-
-      {:ok, _} = Application.ensure_all_started(:some_app)
-
-  When an application starts, developers may configure a callback module
-  that executes custom code. Developers use this callback to start the
-  application supervision tree.
-
-  The first step to do so is to add a `:mod` key to the `application/0`
-  definition in your `mix.exs` file. It expects a tuple, with the application
-  callback module and start argument (commonly an empty list):
+  The `mod` key of an application resource file configures an application
+  callback module and start argument:
 
       def application do
         [mod: {MyApp, []}]
       end
 
+  This key is optional, only needed for applications that start a supervision tree.
+
   The `MyApp` module given to `:mod` needs to implement the `Application` behaviour.
   This can be done by putting `use Application` in that module and implementing the
   `c:start/2` callback, for example:
@@ -184,20 +116,7 @@ defmodule Application do
   tree is terminated. Its argument is the state returned by `c:start/2`, if it did,
   or `[]` otherwise, and its return value is passed to `c:stop/1`.
 
-  ## The application resource file
-
-  In the sections above, we have configured an application in the
-  `application/0` section of the `mix.exs` file. Ultimately, Mix will use
-  this configuration to create an [*application resource
-  file*](https://www.erlang.org/doc/man/application.html), which is a file called
-  `APP_NAME.app`. For example, the application resource file of the OTP
-  application `ex_unit` is called `ex_unit.app`.
-
-  You can learn more about the generation of application resource files in
-  the documentation of `Mix.Tasks.Compile.App`, available as well by running
-  `mix help compile.app`.
-
-  ## The application life cycle
+  ## The application lifecycle
 
   ### Loading applications
 
@@ -207,8 +126,16 @@ defmodule Application do
       Application.load(:ex_unit)
       #=> :ok
 
+  If an application has included applications, they are also loaded. And the
+  procedure recurses if they in turn have included applications. Included
+  applications are unrelated to applications in Mix umbrella projects, they are
+  an Erlang/OTP concept that has to do with coordinated starts.
+
   When an application is loaded, the environment specified in its resource file
-  is merged with any overrides from config files.
+  is merged with any overrides from config files passed to `erl` via the
+  `-config` option. It is worth highlighting that releases pass `sys.config`
+  this way. The resulting environment can still be overridden again via specific
+  `-Application` flags passed to `erl`.
 
   Loading an application *does not* load its modules.
 
@@ -228,15 +155,17 @@ defmodule Application do
   system. Instead, you start one or more applications, each with their own
   initialization and termination logic.
 
-  When an application is started, the `Application.load/1` is automatically
-  invoked if it hasn't been done yet. Then, it checks if the dependencies listed
-  in the `applications` key of the resource file are already started. Having at
-  least one dependency not started is an error condition. Functions like
-  `ensure_all_started/1` takes care of starting an application and all of its
-  dependencies for you.
+  When an application is started, the runtime loads it if it hasn't been loaded
+  yet (in the technical sense described above). Then, it checks if the
+  dependencies listed in the `applications` key of the resource file are already
+  started. Having at least one dependency not started is an error condition, but
+  when you start an application with `mix run`, Mix takes care of starting all
+  the dependencies for you, so in practice you don't need to worry about it
+  unless you are starting applications manually with the API provided by this
+  module.
 
   If the application does not have a callback module configured, starting is
-  done at this point. Otherwise, its `c:start/2` callback is invoked. The PID of
+  done at this point. Otherwise, its `c:start/2` callback if invoked. The PID of
   the top-level supervisor returned by this function is stored by the runtime
   for later use, and the returned application state is saved too, if any.
 
@@ -252,9 +181,9 @@ defmodule Application do
 
   Stopping an application with a callback module has three steps:
 
-    1. If present, invoke the optional callback `c:prep_stop/1`.
-    2. Terminate the top-level supervisor.
-    3. Invoke the required callback `c:stop/1`.
+  1. If present, invoke the optional callback `c:prep_stop/1`.
+  2. Terminate the top-level supervisor.
+  3. Invoke the required callback `c:stop/1`.
 
   The arguments passed to the callbacks are related to the state optionally
   returned by `c:start/2`, and are documented in the section about the callback
@@ -268,22 +197,23 @@ defmodule Application do
   Shutting down a live system cleanly can be done by calling `System.stop/1`. It
   will shut down every application in the opposite order they had been started.
 
-  By default, a SIGTERM from the operating system will automatically translate to
-  `System.stop/0`. You can also have more explicit control over operating system
-  signals via the `:os.set_signal/2` function.
+  From Erlang/OTP 19.1, a SIGTERM from the operating system will automatically
+  translate to `System.stop/0`. Erlang/OTP 20 gives user more explicit control
+  over OS signals via the `:os.set_signal/2` function.
 
   ## Tooling
 
-  The Mix build tool automates most of the application management tasks. For example,
+  The Mix build tool can also be used to start your applications. For example,
   `mix test` automatically starts your application dependencies and your application
   itself before your test runs. `mix run --no-halt` boots your current project and
   can be used to start a long running system. See `mix help run`.
 
-  Developers can also use `mix release` to build **releases**. Releases are able to
-  package all of your source code as well as the Erlang VM into a single directory.
-  Releases also give you explicit control over how each application is started and in
-  which order. They also provide a more streamlined mechanism for starting and
-  stopping systems, debugging, logging, as well as system monitoring.
+  Developers can also use tools like [Distillery](https://github.com/bitwalker/distillery)
+  that build **releases**. Releases are able to package all of your source code
+  as well as the Erlang VM into a single directory. Releases also give you explicit
+  control over how each application is started and in which order. They also provide
+  a more streamlined mechanism for starting and stopping systems, debugging, logging,
+  as well as system monitoring.
 
   Finally, Elixir provides tools such as escripts and archives, which are
   different mechanisms for packaging your application. Those are typically used
@@ -293,10 +223,11 @@ defmodule Application do
   ## Further information
 
   For further details on applications please check the documentation of the
-  [`:application` Erlang module](`:application`), and the
-  [Applications](https://www.erlang.org/doc/design_principles/applications.html)
+  [`application`](http://www.erlang.org/doc/man/application.html) Erlang module,
+  and the
+  [Applications](http://www.erlang.org/doc/design_principles/applications.html)
   section of the [OTP Design Principles User's
-  Guide](https://www.erlang.org/doc/design_principles/users_guide.html).
+  Guide](http://erlang.org/doc/design_principles/users_guide.html).
   """
 
   @doc """
@@ -322,7 +253,7 @@ defmodule Application do
       application specification key `:start_phases` is not `:undefined`.
 
   `start_args` are the arguments passed to the application in the `:mod`
-  specification key (for example, `mod: {MyApp, [:my_args]}`).
+  specification key (e.g., `mod: {MyApp, [:my_args]}`).
 
   This function should either return `{:ok, pid}` or `{:ok, pid, state}` if
   startup is successful. `pid` should be the PID of the top supervisor. `state`
@@ -365,7 +296,7 @@ defmodule Application do
   @callback stop(state) :: term
 
   @doc """
-  Starts an application in synchronous phases.
+  Start an application in synchronous phases.
 
   This function is called after `start/2` finishes but before
   `Application.start/2` returns. It will be called once for every start phase
@@ -375,18 +306,7 @@ defmodule Application do
   @callback start_phase(phase :: term, start_type, phase_args :: term) ::
               :ok | {:error, reason :: term}
 
-  @doc """
-  Callback invoked after code upgrade, if the application environment
-  has changed.
-
-  `changed` is a keyword list of keys and their changed values in the
-  application environment. `new` is a keyword list with all new keys
-  and their values. `removed` is a list with all removed keys.
-  """
-  @callback config_change(changed, new, removed) :: :ok
-            when changed: keyword, new: keyword, removed: [atom]
-
-  @optional_callbacks start_phase: 3, prep_stop: 1, config_change: 3
+  @optional_callbacks start_phase: 3, prep_stop: 1
 
   @doc false
   defmacro __using__(_) do
@@ -402,6 +322,13 @@ defmodule Application do
     end
   end
 
+  @type app :: atom
+  @type key :: atom
+  @type value :: term
+  @type state :: term
+  @type start_type :: :normal | {:takeover, node} | {:failover, node}
+  @type restart_type :: :permanent | :transient | :temporary
+
   @application_keys [
     :description,
     :id,
@@ -411,22 +338,11 @@ defmodule Application do
     :maxT,
     :registered,
     :included_applications,
-    :optional_applications,
     :applications,
     :mod,
     :start_phases
   ]
 
-  application_key_specs = Enum.reduce(@application_keys, &{:|, [], [&1, &2]})
-
-  @type app :: atom
-  @type key :: atom
-  @type application_key :: unquote(application_key_specs)
-  @type value :: term
-  @type state :: term
-  @type start_type :: :normal | {:takeover, node} | {:failover, node}
-  @type restart_type :: :permanent | :transient | :temporary
-
   @doc """
   Returns the spec for `app`.
 
@@ -437,8 +353,8 @@ defmodule Application do
   Note the environment is not returned as it can be accessed via
   `fetch_env/2`. Returns `nil` if the application is not loaded.
   """
-  @spec spec(app) :: [{application_key, value}] | nil
-  def spec(app) when is_atom(app) do
+  @spec spec(app) :: [{key, value}] | nil
+  def spec(app) do
     case :application.get_all_key(app) do
       {:ok, info} -> :lists.keydelete(:env, 1, info)
       :undefined -> nil
@@ -452,8 +368,8 @@ defmodule Application do
   specification parameter does not exist, this function
   will raise. Returns `nil` if the application is not loaded.
   """
-  @spec spec(app, application_key) :: value | nil
-  def spec(app, key) when is_atom(app) and key in @application_keys do
+  @spec spec(app, key) :: value | nil
+  def spec(app, key) when key in @application_keys do
     case :application.get_key(app, key) do
       {:ok, value} -> value
       :undefined -> nil
@@ -479,167 +395,16 @@ defmodule Application do
   Returns all key-value pairs for `app`.
   """
   @spec get_all_env(app) :: [{key, value}]
-  def get_all_env(app) when is_atom(app) do
+  def get_all_env(app) do
     :application.get_all_env(app)
   end
 
-  @doc """
-  Reads the application environment at compilation time.
-
-  Similar to `get_env/3`, except it must be used to read values
-  at compile time. This allows Elixir to track when configuration
-  values change between compile time and runtime.
-
-  The first argument is the application name. The second argument
-  `key_or_path` is either an atom key or a path to traverse in
-  search of the configuration, starting with an atom key.
-
-  For example, imagine the following configuration:
-
-      config :my_app, :key, [foo: [bar: :baz]]
-
-  We can access it during compile time as:
-
-      Application.compile_env(:my_app, :key)
-      #=> [foo: [bar: :baz]]
-
-      Application.compile_env(:my_app, [:key, :foo])
-      #=> [bar: :baz]
-
-      Application.compile_env(:my_app, [:key, :foo, :bar])
-      #=> :baz
-
-  A default value can also be given as third argument. If
-  any of the keys in the path along the way is missing, the
-  default value is used:
-
-      Application.compile_env(:my_app, [:unknown, :foo, :bar], :default)
-      #=> :default
-
-      Application.compile_env(:my_app, [:key, :unknown, :bar], :default)
-      #=> :default
-
-      Application.compile_env(:my_app, [:key, :foo, :unknown], :default)
-      #=> :default
-
-  Giving a path is useful to let Elixir know that only certain paths
-  in a large configuration are compile time dependent.
-  """
-  @doc since: "1.10.0"
-  @spec compile_env(app, key | list, value) :: value
-  defmacro compile_env(app, key_or_path, default \\ nil) do
-    if __CALLER__.function do
-      raise "Application.compile_env/3 cannot be called inside functions, only in the module body"
-    end
-
-    key_or_path = Macro.expand_literals(key_or_path, %{__CALLER__ | function: {:__info__, 1}})
-
-    quote do
-      Application.compile_env(__ENV__, unquote(app), unquote(key_or_path), unquote(default))
-    end
-  end
-
-  @doc """
-  Reads the application environment at compilation time from a macro.
-
-  Typically, developers will use `compile_env/3`. This function must
-  only be invoked from macros which aim to read the compilation environment
-  dynamically.
-
-  It expects a `Macro.Env` as first argument, where the `Macro.Env` is
-  typically the `__CALLER__` in a macro. It raises if `Macro.Env` comes
-  from a function.
-  """
-  @doc since: "1.14.0"
-  @spec compile_env(Macro.Env.t(), app, key | list, value) :: value
-  def compile_env(%Macro.Env{} = env, app, key_or_path, default) do
-    case fetch_compile_env(app, key_or_path, env) do
-      {:ok, value} -> value
-      :error -> default
-    end
-  end
-
-  @doc """
-  Reads the application environment at compilation time or raises.
-
-  This is the same as `compile_env/3` but it raises an
-  `ArgumentError` if the configuration is not available.
-  """
-  @doc since: "1.10.0"
-  @spec compile_env!(app, key | list) :: value
-  defmacro compile_env!(app, key_or_path) do
-    if __CALLER__.function do
-      raise "Application.compile_env!/2 cannot be called inside functions, only in the module body"
-    end
-
-    key_or_path = Macro.expand_literals(key_or_path, %{__CALLER__ | function: {:__info__, 1}})
-
-    quote do
-      Application.compile_env!(__ENV__, unquote(app), unquote(key_or_path))
-    end
-  end
-
-  @doc """
-  Reads the application environment at compilation time from a macro
-  or raises.
-
-  Typically, developers will use `compile_env!/2`. This function must
-  only be invoked from macros which aim to read the compilation environment
-  dynamically.
-
-  It expects a `Macro.Env` as first argument, where the `Macro.Env` is
-  typically the `__CALLER__` in a macro. It raises if `Macro.Env` comes
-  from a function.
-  """
-  @doc since: "1.14.0"
-  @spec compile_env!(Macro.Env.t(), app, key | list) :: value
-  def compile_env!(%Macro.Env{} = env, app, key_or_path) do
-    case fetch_compile_env(app, key_or_path, env) do
-      {:ok, value} ->
-        value
-
-      :error ->
-        raise ArgumentError,
-              "could not fetch application environment #{inspect(key_or_path)} for application " <>
-                "#{inspect(app)} #{fetch_env_failed_reason(app, key_or_path)}"
-    end
-  end
-
-  defp fetch_compile_env(app, key, env) when is_atom(key) do
-    fetch_compile_env(app, key, [], env)
-  end
-
-  defp fetch_compile_env(app, [key | paths], env) when is_atom(key),
-    do: fetch_compile_env(app, key, paths, env)
-
-  defp fetch_compile_env(app, key, path, env) do
-    return = traverse_env(fetch_env(app, key), path)
-
-    for tracer <- env.tracers do
-      tracer.trace({:compile_env, app, [key | path], return}, env)
-    end
-
-    return
-  end
-
-  defp traverse_env(return, []), do: return
-  defp traverse_env(:error, _paths), do: :error
-  defp traverse_env({:ok, value}, [key | keys]), do: traverse_env(Access.fetch(value, key), keys)
-
   @doc """
   Returns the value for `key` in `app`'s environment.
 
   If the configuration parameter does not exist, the function returns the
   `default` value.
 
-  > **Important:** you must use this function to read only your own application
-  > environment. Do not read the environment of other applications.
-
-  > **Important:** if you are writing a library to be used by other developers,
-  > it is generally recommended to avoid the application environment, as the
-  > application environment is effectively a global storage. For more information,
-  > read our [library guidelines](library-guidelines.md).
-
   ## Examples
 
   `get_env/3` is commonly used to read the configuration of your OTP applications.
@@ -653,34 +418,30 @@ defmodule Application do
 
       config :my_app, Databases.RepoOne,
         # A database configuration
-        ip: "localhost",
+        ip: "localhost"
         port: 5433
 
       config :my_app, Databases.RepoTwo,
         # Another database configuration (for the same OTP app)
-        ip: "localhost",
+        ip: "localhost"
         port: 20717
 
       config :my_app, my_app_databases: [Databases.RepoOne, Databases.RepoTwo]
 
   Our database engine used by `:my_app` needs to know what databases exist, and
   what the database configurations are. The database engine can make a call to
-  `Application.get_env(:my_app, :my_app_databases, [])` to retrieve the list of
-  databases (specified by module names).
-
-  The engine can then traverse each repository in the list and call
-  `Application.get_env(:my_app, Databases.RepoOne)` and so forth to retrieve the
-  configuration of each one. In this case, each configuration will be a keyword
-  list, so you can use the functions in the `Keyword` module or even the `Access`
-  module to traverse it, for example:
-
-      config = Application.get_env(:my_app, Databases.RepoOne)
-      config[:ip]
+  `get_env(:my_app, :my_app_databases)` to retrieve the list of databases (specified
+  by module names). Our database engine can then traverse each repository in the
+  list and then call `get_env(:my_app, Databases.RepoOne)` and so forth to retrieve
+  the configuration of each one.
 
+  **Important:** if you are writing a library to be used by other developers,
+  it is generally recommended to avoid the application environment, as the
+  application environment is effectively a global storage. For more information,
+  read our [library guidelines](/library-guidelines.html).
   """
   @spec get_env(app, key, value) :: value
-  def get_env(app, key, default \\ nil) when is_atom(app) do
-    maybe_warn_on_app_env_key(app, key)
+  def get_env(app, key, default \\ nil) do
     :application.get_env(app, key, default)
   end
 
@@ -688,19 +449,9 @@ defmodule Application do
   Returns the value for `key` in `app`'s environment in a tuple.
 
   If the configuration parameter does not exist, the function returns `:error`.
-
-  > **Important:** you must use this function to read only your own application
-  > environment. Do not read the environment of other applications.
-
-  > **Important:** if you are writing a library to be used by other developers,
-  > it is generally recommended to avoid the application environment, as the
-  > application environment is effectively a global storage. For more information,
-  > read our [library guidelines](library-guidelines.md).
   """
   @spec fetch_env(app, key) :: {:ok, value} | :error
-  def fetch_env(app, key) when is_atom(app) do
-    maybe_warn_on_app_env_key(app, key)
-
+  def fetch_env(app, key) do
     case :application.get_env(app, key) do
       {:ok, value} -> {:ok, value}
       :undefined -> :error
@@ -711,37 +462,31 @@ defmodule Application do
   Returns the value for `key` in `app`'s environment.
 
   If the configuration parameter does not exist, raises `ArgumentError`.
-
-  > **Important:** you must use this function to read only your own application
-  > environment. Do not read the environment of other applications.
-
-  > **Important:** if you are writing a library to be used by other developers,
-  > it is generally recommended to avoid the application environment, as the
-  > application environment is effectively a global storage. For more information,
-  > read our [library guidelines](library-guidelines.md).
   """
-  @spec fetch_env!(app, key) :: value
-  def fetch_env!(app, key) when is_atom(app) do
+  @spec fetch_env!(app, key) :: value | no_return
+  def fetch_env!(app, key) do
     case fetch_env(app, key) do
       {:ok, value} ->
         value
 
       :error ->
-        raise ArgumentError,
-              "could not fetch application environment #{inspect(key)} for application " <>
-                "#{inspect(app)} #{fetch_env_failed_reason(app, key)}"
-    end
-  end
+        vsn = :application.get_key(app, :vsn)
+        app = inspect(app)
+        key = inspect(key)
 
-  defp fetch_env_failed_reason(app, key) do
-    vsn = :application.get_key(app, :vsn)
+        case vsn do
+          {:ok, _} ->
+            raise ArgumentError,
+                  "could not fetch application environment #{key} for application #{app} " <>
+                    "because configuration #{key} was not set"
 
-    case vsn do
-      {:ok, _} ->
-        "because configuration at #{inspect(key)} was not set"
-
-      :undefined ->
-        "because the application was not loaded nor configured"
+          :undefined ->
+            raise ArgumentError,
+                  "could not fetch application environment #{key} for application #{app} " <>
+                    "because the application was not loaded/started. If your application " <>
+                    "depends on #{app} at runtime, make sure to load/start it or list it " <>
+                    "under :extra_applications in your mix.exs file"
+        end
     end
   end
 
@@ -757,55 +502,26 @@ defmodule Application do
   environment values specified in the `.app` file will override the ones
   previously set.
 
-  The `:persistent` option can be set to `true` when there is a need to guarantee
+  The persistent option can be set to `true` when there is a need to guarantee
   parameters set with this function will not be overridden by the ones defined
   in the application resource file on load. This means persistent values will
   stick after the application is loaded and also on application reload.
   """
   @spec put_env(app, key, value, timeout: timeout, persistent: boolean) :: :ok
-  def put_env(app, key, value, opts \\ []) when is_atom(app) do
-    maybe_warn_on_app_env_key(app, key)
+  def put_env(app, key, value, opts \\ []) do
     :application.set_env(app, key, value, opts)
   end
 
-  @doc """
-  Puts the environment for multiple apps at the same time.
-
-  The given config should not:
-
-    * have the same application listed more than once
-    * have the same key inside the same application listed more than once
-
-  If those conditions are not met, it will raise.
-
-  It receives the same options as `put_env/4`. Returns `:ok`.
-  """
-  @doc since: "1.9.0"
-  @spec put_all_env([{app, [{key, value}]}], timeout: timeout, persistent: boolean) :: :ok
-  def put_all_env(config, opts \\ []) when is_list(config) and is_list(opts) do
-    :application.set_env(config, opts)
-  end
-
   @doc """
   Deletes the `key` from the given `app` environment.
 
-  It receives the same options as `put_env/4`. Returns `:ok`.
+  See `put_env/4` for a description of the options.
   """
   @spec delete_env(app, key, timeout: timeout, persistent: boolean) :: :ok
-  def delete_env(app, key, opts \\ []) when is_atom(app) do
-    maybe_warn_on_app_env_key(app, key)
+  def delete_env(app, key, opts \\ []) do
     :application.unset_env(app, key, opts)
   end
 
-  defp maybe_warn_on_app_env_key(_app, key) when is_atom(key),
-    do: :ok
-
-  # TODO: Remove this deprecation warning on 2.0+ and allow list lookups as in compile_env.
-  defp maybe_warn_on_app_env_key(app, key) do
-    message = "passing non-atom as application env key is deprecated, got: #{inspect(key)}"
-    IO.warn_once({Application, :key, app, key}, message, _stacktrace_drop_levels = 2)
-  end
-
   @doc """
   Ensures the given `app` is started.
 
@@ -821,22 +537,6 @@ defmodule Application do
     :application.ensure_started(app, type)
   end
 
-  @doc """
-  Ensures the given `app` is loaded.
-
-  Same as `load/1` but returns `:ok` if the application was already
-  loaded.
-  """
-  @doc since: "1.10.0"
-  @spec ensure_loaded(app) :: :ok | {:error, term}
-  def ensure_loaded(app) when is_atom(app) do
-    case :application.load(app) do
-      :ok -> :ok
-      {:error, {:already_loaded, ^app}} -> :ok
-      {:error, _} = error -> error
-    end
-  end
-
   @doc """
   Ensures the given `app` and its applications are started.
 
@@ -894,7 +594,7 @@ defmodule Application do
   When stopped, the application is still loaded.
   """
   @spec stop(app) :: :ok | {:error, term}
-  def stop(app) when is_atom(app) do
+  def stop(app) do
     :application.stop(app)
   end
 
@@ -945,7 +645,7 @@ defmodule Application do
       #=> "bar-123"
 
   For more information on code paths, check the `Code` module in
-  Elixir and also Erlang's [`:code` module](`:code`).
+  Elixir and also Erlang's [`:code` module](http://www.erlang.org/doc/man/code.html).
   """
   @spec app_dir(app) :: String.t()
   def app_dir(app) when is_atom(app) do
@@ -977,11 +677,11 @@ defmodule Application do
   @spec app_dir(app, String.t() | [String.t()]) :: String.t()
   def app_dir(app, path)
 
-  def app_dir(app, path) when is_atom(app) and is_binary(path) do
+  def app_dir(app, path) when is_binary(path) do
     Path.join(app_dir(app), path)
   end
 
-  def app_dir(app, path) when is_atom(app) and is_list(path) do
+  def app_dir(app, path) when is_list(path) do
     Path.join([app_dir(app) | path])
   end
 

lib/elixir/lib/atom.ex

@@ -1,46 +1,8 @@
 defmodule Atom do
   @moduledoc """
-  Atoms are constants whose values are their own name.
-
-  They are often useful to enumerate over distinct values, such as:
-
-      iex> :apple
-      :apple
-      iex> :orange
-      :orange
-      iex> :watermelon
-      :watermelon
-
-  Atoms are equal if their names are equal.
-
-      iex> :apple == :apple
-      true
-      iex> :apple == :orange
-      false
-
-  Often they are used to express the state of an operation, by using
-  values such as `:ok` and `:error`.
-
-  The booleans `true` and `false` are also atoms:
-
-      iex> true == :true
-      true
-      iex> is_atom(false)
-      true
-      iex> is_boolean(:false)
-      true
-
-  Elixir allows you to skip the leading `:` for the atoms `false`, `true`,
-  and `nil`.
-
-  Atoms must be composed of Unicode characters such as letters, numbers,
-  underscore, and `@`. If the keyword has a character that does not
-  belong to the category above, such as spaces, you can wrap it in
-  quotes:
-
-      iex> :"this is an atom with spaces"
-      :"this is an atom with spaces"
+  Convenience functions for working with atoms.
 
+  See also `Kernel.is_atom/1`.
   """
 
   @doc """
@@ -56,7 +18,7 @@ defmodule Atom do
   """
   @spec to_string(atom) :: String.t()
   def to_string(atom) do
-    :erlang.atom_to_binary(atom)
+    :erlang.atom_to_binary(atom, :utf8)
   end
 
   @doc """
@@ -75,6 +37,7 @@ defmodule Atom do
     :erlang.atom_to_list(atom)
   end
 
+  # TODO: Remove by 2.0
   @doc false
   @deprecated "Use Atom.to_charlist/1 instead"
   @spec to_char_list(atom) :: charlist

lib/elixir/lib/behaviour.ex

@@ -4,7 +4,7 @@ defmodule Behaviour do
 
   This module is deprecated. Instead of `defcallback/1` and
   `defmacrocallback/1`, the `@callback` and `@macrocallback`
-  module attributes can be used respectively. See the
+  module attributes can be used (respectively). See the
   documentation for `Module` for more information on these
   attributes.
 
@@ -17,7 +17,6 @@ defmodule Behaviour do
   @doc """
   Defines a function callback according to the given type specification.
   """
-  @deprecated "Use the @callback module attribute instead"
   defmacro defcallback(spec) do
     do_defcallback(:def, split_spec(spec, quote(do: term)))
   end
@@ -25,12 +24,11 @@ defmodule Behaviour do
   @doc """
   Defines a macro callback according to the given type specification.
   """
-  @deprecated "Use the @macrocallback module attribute instead"
   defmacro defmacrocallback(spec) do
     do_defcallback(:defmacro, split_spec(spec, quote(do: Macro.t())))
   end
 
-  defp split_spec({:when, _, [{:"::", _, [spec, return]}, guard]}, _default) do
+  defp split_spec({:when, _, [{:::, _, [spec, return]}, guard]}, _default) do
     {spec, return, guard}
   end
 
@@ -38,7 +36,7 @@ defmodule Behaviour do
     {spec, default, guard}
   end
 
-  defp split_spec({:"::", _, [spec, return]}, _default) do
+  defp split_spec({:::, _, [spec, return]}, _default) do
     {spec, return, []}
   end
 
@@ -58,7 +56,7 @@ defmodule Behaviour do
 
   defp do_callback(kind, name, args, return, guards) do
     fun = fn
-      {:"::", _, [left, right]} ->
+      {:::, _, [left, right]} ->
         ensure_not_default(left)
         ensure_not_default(right)
         left
@@ -113,9 +111,9 @@ defmodule Behaviour do
         end
       end
 
-      defp __behaviour__doc_value(%{"en" => doc}), do: doc
+      defp __behaviour__doc_value(:none), do: nil
       defp __behaviour__doc_value(:hidden), do: false
-      defp __behaviour__doc_value(_), do: nil
+      defp __behaviour__doc_value(%{"en" => doc}), do: doc
 
       import unquote(__MODULE__)
     end

lib/elixir/lib/bitwise.ex

@@ -1,28 +1,44 @@
 defmodule Bitwise do
   @moduledoc """
-  A set of functions that perform calculations on bits.
+  A set of macros that perform calculations on bits.
 
-  All bitwise functions work only on integers; otherwise an
-  `ArithmeticError` is raised. The functions `band/2`,
-  `bor/2`, `bsl/2`, and `bsr/2` also have operators,
-  respectively: `&&&/2`, `|||/2`, `<<</2`, and `>>>/2`.
+  The macros in this module come in two flavors: named or
+  operators. For example:
 
-  ## Guards
+      iex> use Bitwise
+      iex> bnot(1) # named
+      -2
+      iex> 1 &&& 1 # operator
+      1
 
-  All bitwise functions can be used in guards:
+  If you prefer to use only operators or skip them, you can
+  pass the following options:
 
+    * `:only_operators` - includes only operators
+    * `:skip_operators` - skips operators
+
+  For example:
+
+      iex> use Bitwise, only_operators: true
+      iex> 1 &&& 1
+      1
+
+  When invoked with no options, `use Bitwise` is equivalent
+  to `import Bitwise`.
+
+  All bitwise macros can be used in guards:
+
+      iex> use Bitwise
       iex> odd? = fn
-      ...>   int when Bitwise.band(int, 1) == 1 -> true
+      ...>   int when band(int, 1) == 1 -> true
       ...>   _ -> false
       ...> end
       iex> odd?.(1)
       true
 
-  All functions in this module are inlined by the compiler.
   """
 
   @doc false
-  @deprecated "import Bitwise instead"
   defmacro __using__(options) do
     except =
       cond do
@@ -30,7 +46,7 @@ defmodule Bitwise do
           [bnot: 1, band: 2, bor: 2, bxor: 2, bsl: 2, bsr: 2]
 
         Keyword.get(options, :skip_operators) ->
-          ["~~~": 1, &&&: 2, |||: 2, "^^^": 2, <<<: 2, >>>: 2]
+          [~~~: 1, &&&: 2, |||: 2, ^^^: 2, <<<: 2, >>>: 2]
 
         true ->
           []
@@ -42,229 +58,162 @@ defmodule Bitwise do
   end
 
   @doc """
-  Calculates the bitwise NOT of the argument.
-
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
+  Calculates the bitwise NOT of its argument.
 
       iex> bnot(2)
       -3
-
       iex> bnot(2) &&& 3
       1
 
   """
-  @doc guard: true
-  @spec bnot(integer) :: integer
-  def bnot(expr) do
-    :erlang.bnot(expr)
+  defmacro bnot(expr) do
+    quote(do: :erlang.bnot(unquote(expr)))
   end
 
-  @doc false
-  def unquote(:"~~~")(expr) do
-    :erlang.bnot(expr)
+  @doc """
+  Prefix (unary) operator; calculates the bitwise NOT of its argument.
+
+      iex> ~~~2
+      -3
+      iex> ~~~2 &&& 3
+      1
+
+  """
+  defmacro ~~~expr do
+    quote(do: :erlang.bnot(unquote(expr)))
   end
 
   @doc """
   Calculates the bitwise AND of its arguments.
 
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
-
       iex> band(9, 3)
       1
 
   """
-  @doc guard: true
-  @spec band(integer, integer) :: integer
-  def band(left, right) do
-    :erlang.band(left, right)
+  defmacro band(left, right) do
+    quote(do: :erlang.band(unquote(left), unquote(right)))
   end
 
   @doc """
-  Bitwise AND operator.
-
-  Calculates the bitwise AND of its arguments.
-
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
+  Infix operator; calculates the bitwise AND of its arguments.
 
       iex> 9 &&& 3
       1
 
   """
-  @doc guard: true
-  @spec integer &&& integer :: integer
-  def left &&& right do
-    :erlang.band(left, right)
+  defmacro left &&& right do
+    quote(do: :erlang.band(unquote(left), unquote(right)))
   end
 
   @doc """
   Calculates the bitwise OR of its arguments.
 
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
-
       iex> bor(9, 3)
       11
 
   """
-  @doc guard: true
-  @spec bor(integer, integer) :: integer
-  def bor(left, right) do
-    :erlang.bor(left, right)
+  defmacro bor(left, right) do
+    quote(do: :erlang.bor(unquote(left), unquote(right)))
   end
 
   @doc """
-  Bitwise OR operator.
-
-  Calculates the bitwise OR of its arguments.
-
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
+  Infix operator; calculates the bitwise OR of its arguments.
 
       iex> 9 ||| 3
       11
 
   """
-  @doc guard: true
-  @spec integer ||| integer :: integer
-  def left ||| right do
-    :erlang.bor(left, right)
+  defmacro left ||| right do
+    quote(do: :erlang.bor(unquote(left), unquote(right)))
   end
 
   @doc """
   Calculates the bitwise XOR of its arguments.
 
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
-
       iex> bxor(9, 3)
       10
 
   """
-  @doc guard: true
-  @spec bxor(integer, integer) :: integer
-  def bxor(left, right) do
-    :erlang.bxor(left, right)
+  defmacro bxor(left, right) do
+    quote(do: :erlang.bxor(unquote(left), unquote(right)))
   end
 
-  @doc false
-  def unquote(:"^^^")(left, right) do
-    :erlang.bxor(left, right)
+  @doc """
+  Infix operator; calculates the bitwise XOR of its arguments.
+
+      iex> 9 ^^^ 3
+      10
+
+  """
+  defmacro left ^^^ right do
+    quote(do: :erlang.bxor(unquote(left), unquote(right)))
   end
 
   @doc """
   Calculates the result of an arithmetic left bitshift.
 
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
-
       iex> bsl(1, 2)
       4
-
       iex> bsl(1, -2)
       0
-
       iex> bsl(-1, 2)
       -4
-
       iex> bsl(-1, -2)
       -1
 
   """
-  @doc guard: true
-  @spec bsl(integer, integer) :: integer
-  def bsl(left, right) do
-    :erlang.bsl(left, right)
+  defmacro bsl(left, right) do
+    quote(do: :erlang.bsl(unquote(left), unquote(right)))
   end
 
   @doc """
-  Arithmetic left bitshift operator.
-
-  Calculates the result of an arithmetic left bitshift.
-
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
+  Infix operator; calculates the result of an arithmetic left bitshift.
 
       iex> 1 <<< 2
       4
-
       iex> 1 <<< -2
       0
-
       iex> -1 <<< 2
       -4
-
       iex> -1 <<< -2
       -1
 
   """
-  @doc guard: true
-  @spec integer <<< integer :: integer
-  def left <<< right do
-    :erlang.bsl(left, right)
+  defmacro left <<< right do
+    quote(do: :erlang.bsl(unquote(left), unquote(right)))
   end
 
   @doc """
   Calculates the result of an arithmetic right bitshift.
 
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
-
       iex> bsr(1, 2)
       0
-
       iex> bsr(1, -2)
       4
-
       iex> bsr(-1, 2)
       -1
-
       iex> bsr(-1, -2)
       -4
 
   """
-  @doc guard: true
-  @spec bsr(integer, integer) :: integer
-  def bsr(left, right) do
-    :erlang.bsr(left, right)
+  defmacro bsr(left, right) do
+    quote(do: :erlang.bsr(unquote(left), unquote(right)))
   end
 
   @doc """
-  Arithmetic right bitshift operator.
-
-  Calculates the result of an arithmetic right bitshift.
-
-  Allowed in guard tests. Inlined by the compiler.
-
-  ## Examples
+  Infix operator; calculates the result of an arithmetic right bitshift.
 
       iex> 1 >>> 2
       0
-
       iex> 1 >>> -2
       4
-
       iex> -1 >>> 2
       -1
-
       iex> -1 >>> -2
       -4
 
   """
-  @doc guard: true
-  @spec integer >>> integer :: integer
-  def left >>> right do
-    :erlang.bsr(left, right)
+  defmacro left >>> right do
+    quote(do: :erlang.bsr(unquote(left), unquote(right)))
   end
 end

lib/elixir/lib/calendar.ex

@@ -11,26 +11,17 @@ defmodule Calendar do
   For the actual date, time and datetime structures, see `Date`,
   `Time`, `NaiveDateTime` and `DateTime`.
 
-  Note designations for year, month, day, and the like, are overspecified
+  Note the year, month, day, etc. designations are overspecified
   (i.e. an integer instead of `1..12` for months) because different
   calendars may have a different number of days per month, months per year and so on.
   """
 
   @type year :: integer
-  @type month :: pos_integer
-  @type day :: pos_integer
-  @type week :: pos_integer
-  @type day_of_week :: non_neg_integer
-  @type era :: non_neg_integer
-
-  @typedoc """
-  A tuple representing the `day` and the `era`.
-  """
-  @type day_of_era :: {day :: non_neg_integer(), era}
-
-  @type hour :: non_neg_integer
-  @type minute :: non_neg_integer
-  @type second :: non_neg_integer
+  @type month :: integer
+  @type day :: integer
+  @type hour :: integer
+  @type minute :: integer
+  @type second :: integer
 
   @typedoc """
   The internal time format is used when converting between calendars.
@@ -45,8 +36,13 @@ defmodule Calendar do
   The internal date format that is used when converting between calendars.
 
   This is the number of days including the fractional part that has passed of
-  the last day since 0000-01-01+00:00T00:00.000000 in ISO 8601 notation (also
+  the last day since 0000-01-01+00:00T00:00.00000 in ISO 8601 notation (also
   known as midnight 1 January BC 1 of the proleptic Gregorian calendar).
+
+  The `parts_per_day` represent how many subparts the current day is subdivided in
+  (for different calendars, picking a different `parts_per_day` might make sense).
+  The `parts_in_day` represents how many of these `parts_per_day` have passed in the
+  last day.
   """
   @type iso_days :: {days :: integer, day_fraction}
 
@@ -57,29 +53,21 @@ defmodule Calendar do
   representing the microseconds to external format. If the precision is 0,
   it means microseconds must be skipped.
   """
-  @type microsecond :: {value :: non_neg_integer, precision :: non_neg_integer}
+  @type microsecond :: {0..999_999, 0..6}
 
   @typedoc "A calendar implementation"
   @type calendar :: module
 
-  @typedoc "The time zone ID according to the IANA tz database (for example, Europe/Zurich)"
+  @typedoc "The time zone ID according to the IANA tz database (e.g. Europe/Zurich)"
   @type time_zone :: String.t()
 
-  @typedoc "The time zone abbreviation (for example, CET or CEST or BST, and such)"
+  @typedoc "The time zone abbreviation (e.g. CET or CEST or BST etc.)"
   @type zone_abbr :: String.t()
 
-  @typedoc """
-  The time zone UTC offset in seconds for standard time.
-
-  See also `t:std_offset/0`.
-  """
+  @typedoc "The time zone UTC offset in seconds"
   @type utc_offset :: integer
 
-  @typedoc """
-  The time zone standard offset in seconds (typically not zero in summer times).
-
-  It must be added to `t:utc_offset/0` to get the total offset from UTC used for "wall time".
-  """
+  @typedoc "The time zone standard offset in seconds (not zero in summer times)"
   @type std_offset :: integer
 
   @typedoc "Any map/struct that contains the date fields"
@@ -124,28 +112,6 @@ defmodule Calendar do
           std_offset: std_offset
         }
 
-  @typedoc """
-  Specifies the time zone database for calendar operations.
-
-  Many functions in the `DateTime` module require a time zone database.
-  By default, it uses the default time zone database returned by
-  `Calendar.get_time_zone_database/0`, which defaults to
-  `Calendar.UTCOnlyTimeZoneDatabase` which only handles "Etc/UTC"
-  datetimes and returns `{:error, :utc_only_time_zone_database}`
-  for any other time zone.
-
-  Other time zone databases (including ones provided by packages)
-  can be configured as default either via configuration:
-
-      config :elixir, :time_zone_database, CustomTimeZoneDatabase
-
-  or by calling `Calendar.put_time_zone_database/1`.
-
-  See `Calendar.TimeZoneDatabase` for more information on custom
-  time zone databases.
-  """
-  @type time_zone_database :: module()
-
   @doc """
   Returns how many days there are in the given year-month.
   """
@@ -167,34 +133,8 @@ defmodule Calendar do
 
   @doc """
   Calculates the day of the week from the given `year`, `month`, and `day`.
-
-  The `starting_on` represents the starting day of the week. All
-  calendars must support at least the `:default` value. They may
-  also support other values representing their days of the week.
   """
-  @callback day_of_week(year, month, day, starting_on :: :default | atom) ::
-              {day_of_week(), first_day_of_week :: non_neg_integer(),
-               last_day_of_week :: non_neg_integer()}
-
-  @doc """
-  Calculates the day of the year from the given `year`, `month`, and `day`.
-  """
-  @callback day_of_year(year, month, day) :: non_neg_integer()
-
-  @doc """
-  Calculates the quarter of the year from the given `year`, `month`, and `day`.
-  """
-  @callback quarter_of_year(year, month, day) :: non_neg_integer()
-
-  @doc """
-  Calculates the year and era from the given `year`.
-  """
-  @callback year_of_era(year, month, day) :: {year, era}
-
-  @doc """
-  Calculates the day and era from the given `year`, `month`, and `day`.
-  """
-  @callback day_of_era(year, month, day) :: day_of_era()
+  @callback day_of_week(year, month, day) :: non_neg_integer()
 
   @doc """
   Converts the date into a string according to the calendar.
@@ -230,7 +170,7 @@ defmodule Calendar do
   @callback time_to_string(hour, minute, second, microsecond) :: String.t()
 
   @doc """
-  Converts the given datetime (without time zone) into the `t:iso_days/0` format.
+  Converts the given datetime (with time zone) into the `t:iso_days/0` format.
   """
   @callback naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond) ::
               iso_days
@@ -284,47 +224,6 @@ defmodule Calendar do
   """
   @callback valid_time?(hour, minute, second, microsecond) :: boolean
 
-  @doc """
-  Parses the string representation for a time returned by `c:time_to_string/4`
-  into a time-tuple.
-  """
-  @doc since: "1.10.0"
-  @callback parse_time(String.t()) ::
-              {:ok, {hour, minute, second, microsecond}}
-              | {:error, atom}
-
-  @doc """
-  Parses the string representation for a date returned by `c:date_to_string/3`
-  into a date-tuple.
-  """
-  @doc since: "1.10.0"
-  @callback parse_date(String.t()) ::
-              {:ok, {year, month, day}}
-              | {:error, atom}
-
-  @doc """
-  Parses the string representation for a naive datetime returned by
-  `c:naive_datetime_to_string/7` into a naive-datetime-tuple.
-
-  The given string may contain a timezone offset but it is ignored.
-  """
-  @doc since: "1.10.0"
-  @callback parse_naive_datetime(String.t()) ::
-              {:ok, {year, month, day, hour, minute, second, microsecond}}
-              | {:error, atom}
-
-  @doc """
-  Parses the string representation for a datetime returned by
-  `c:datetime_to_string/11` into a datetime-tuple.
-
-  The returned datetime must be in UTC. The original `utc_offset`
-  it was written in must be returned in the result.
-  """
-  @doc since: "1.10.0"
-  @callback parse_utc_datetime(String.t()) ::
-              {:ok, {year, month, day, hour, minute, second, microsecond}, utc_offset}
-              | {:error, atom}
-
   # General Helpers
 
   @doc """
@@ -359,528 +258,4 @@ defmodule Calendar do
   end
 
   def truncate(_, :second), do: {0, 0}
-
-  @doc """
-  Sets the current time zone database.
-  """
-  @doc since: "1.8.0"
-  @spec put_time_zone_database(time_zone_database()) :: :ok
-  def put_time_zone_database(database) when is_atom(database) do
-    Application.put_env(:elixir, :time_zone_database, database)
-  end
-
-  @doc """
-  Gets the current time zone database.
-  """
-  @doc since: "1.8.0"
-  @spec get_time_zone_database() :: time_zone_database()
-  def get_time_zone_database() do
-    Application.fetch_env!(:elixir, :time_zone_database)
-  end
-
-  @doc """
-  Formats received datetime into a string.
-
-  The datetime can be any of the Calendar types (`Time`, `Date`,
-  `NaiveDateTime`, and `DateTime`) or any map, as long as they
-  contain all of the relevant fields necessary for formatting.
-  For example, if you use `%Y` to format the year, the datetime
-  must have the `:year` field. Therefore, if you pass a `Time`,
-  or a map without the `:year` field to a format that expects `%Y`,
-  an error will be raised.
-
-  ## Options
-
-    * `:preferred_datetime` - a string for the preferred format to show datetimes,
-      it can't contain the `%c` format and defaults to `"%Y-%m-%d %H:%M:%S"`
-      if the option is not received
-
-    * `:preferred_date` - a string for the preferred format to show dates,
-      it can't contain the `%x` format and defaults to `"%Y-%m-%d"`
-      if the option is not received
-
-    * `:preferred_time` - a string for the preferred format to show times,
-      it can't contain the `%X` format and defaults to `"%H:%M:%S"`
-      if the option is not received
-
-    * `:am_pm_names` - a function that receives either `:am` or `:pm` and returns
-      the name of the period of the day, if the option is not received it defaults
-      to a function that returns `"am"` and `"pm"`, respectively
-
-    *  `:month_names` - a function that receives a number and returns the name of
-      the corresponding month, if the option is not received it defaults to a
-      function that returns the month names in English
-
-    * `:abbreviated_month_names` - a function that receives a number and returns the
-      abbreviated name of the corresponding month, if the option is not received it
-      defaults to a function that returns the abbreviated month names in English
-
-    * `:day_of_week_names` - a function that receives a number and returns the name of
-      the corresponding day of week, if the option is not received it defaults to a
-      function that returns the day of week names in English
-
-    * `:abbreviated_day_of_week_names` - a function that receives a number and returns
-      the abbreviated name of the corresponding day of week, if the option is not received
-      it defaults to a function that returns the abbreviated day of week names in English
-
-  ## Formatting syntax
-
-  The formatting syntax for strftime is a sequence of characters in the following format:
-
-      %<padding><width><format>
-
-  where:
-
-    * `%`: indicates the start of a formatted section
-    * `<padding>`: set the padding (see below)
-    * `<width>`: a number indicating the minimum size of the formatted section
-    * `<format>`: the format itself (see below)
-
-  ### Accepted padding options
-
-    * `-`: no padding, removes all padding from the format
-    * `_`: pad with spaces
-    * `0`: pad with zeroes
-
-  ### Accepted formats
-
-  The accepted formats are:
-
-  Format | Description                                                             | Examples (in ISO)
-  :----- | :-----------------------------------------------------------------------| :------------------------
-  a      | Abbreviated name of day                                                 | Mon
-  A      | Full name of day                                                        | Monday
-  b      | Abbreviated month name                                                  | Jan
-  B      | Full month name                                                         | January
-  c      | Preferred date+time representation                                      | 2018-10-17 12:34:56
-  d      | Day of the month                                                        | 01, 31
-  f      | Microseconds *(does not support width and padding modifiers)*           | 000000, 999999, 0123
-  H      | Hour using a 24-hour clock                                              | 00, 23
-  I      | Hour using a 12-hour clock                                              | 01, 12
-  j      | Day of the year                                                         | 001, 366
-  m      | Month                                                                   | 01, 12
-  M      | Minute                                                                  | 00, 59
-  p      | "AM" or "PM" (noon is "PM", midnight as "AM")                           | AM, PM
-  P      | "am" or "pm" (noon is "pm", midnight as "am")                           | am, pm
-  q      | Quarter                                                                 | 1, 2, 3, 4
-  S      | Second                                                                  | 00, 59, 60
-  u      | Day of the week                                                         | 1 (Monday), 7 (Sunday)
-  x      | Preferred date (without time) representation                            | 2018-10-17
-  X      | Preferred time (without date) representation                            | 12:34:56
-  y      | Year as 2-digits                                                        | 01, 01, 86, 18
-  Y      | Year                                                                    | -0001, 0001, 1986
-  z      | +hhmm/-hhmm time zone offset from UTC (empty string if naive)           | +0300, -0530
-  Z      | Time zone abbreviation (empty string if naive)                          | CET, BRST
-  %      | Literal "%" character                                                   | %
-
-  Any other character will be interpreted as an invalid format and raise an error
-
-  ## Examples
-
-  Without options:
-
-      iex> Calendar.strftime(~U[2019-08-26 13:52:06.0Z], "%y-%m-%d %I:%M:%S %p")
-      "19-08-26 01:52:06 PM"
-
-      iex> Calendar.strftime(~U[2019-08-26 13:52:06.0Z], "%a, %B %d %Y")
-      "Mon, August 26 2019"
-
-      iex> Calendar.strftime(~U[2020-04-02 13:52:06.0Z], "%B %-d, %Y")
-      "April 2, 2020"
-
-      iex> Calendar.strftime(~U[2019-08-26 13:52:06.0Z], "%c")
-      "2019-08-26 13:52:06"
-
-  With options:
-
-      iex> Calendar.strftime(~U[2019-08-26 13:52:06.0Z], "%c", preferred_datetime: "%H:%M:%S %d-%m-%y")
-      "13:52:06 26-08-19"
-
-      iex> Calendar.strftime(
-      ...>  ~U[2019-08-26 13:52:06.0Z],
-      ...>  "%A",
-      ...>  day_of_week_names: fn day_of_week ->
-      ...>    {"segunda-feira", "terça-feira", "quarta-feira", "quinta-feira",
-      ...>    "sexta-feira", "sábado", "domingo"}
-      ...>    |> elem(day_of_week - 1)
-      ...>  end
-      ...>)
-      "segunda-feira"
-
-      iex> Calendar.strftime(
-      ...>  ~U[2019-08-26 13:52:06.0Z],
-      ...>  "%B",
-      ...>  month_names: fn month ->
-      ...>    {"январь", "февраль", "март", "апрель", "май", "июнь",
-      ...>    "июль", "август", "сентябрь", "октябрь", "ноябрь", "декабрь"}
-      ...>    |> elem(month - 1)
-      ...>  end
-      ...>)
-      "август"
-  """
-  @doc since: "1.11.0"
-  @spec strftime(map(), String.t(), keyword()) :: String.t()
-  def strftime(date_or_time_or_datetime, string_format, user_options \\ [])
-      when is_map(date_or_time_or_datetime) and is_binary(string_format) do
-    parse(
-      string_format,
-      date_or_time_or_datetime,
-      options(user_options),
-      []
-    )
-    |> IO.iodata_to_binary()
-  end
-
-  defp parse("", _datetime, _format_options, acc),
-    do: Enum.reverse(acc)
-
-  defp parse("%" <> rest, datetime, format_options, acc),
-    do: parse_modifiers(rest, nil, nil, {datetime, format_options, acc})
-
-  defp parse(<<char, rest::binary>>, datetime, format_options, acc),
-    do: parse(rest, datetime, format_options, [char | acc])
-
-  defp parse_modifiers("-" <> rest, width, nil, parser_data) do
-    parse_modifiers(rest, width, "", parser_data)
-  end
-
-  defp parse_modifiers("0" <> rest, nil, nil, parser_data) do
-    parse_modifiers(rest, nil, ?0, parser_data)
-  end
-
-  defp parse_modifiers("_" <> rest, width, nil, parser_data) do
-    parse_modifiers(rest, width, ?\s, parser_data)
-  end
-
-  defp parse_modifiers(<<digit, rest::binary>>, width, pad, parser_data) when digit in ?0..?9 do
-    new_width = (width || 0) * 10 + (digit - ?0)
-
-    parse_modifiers(rest, new_width, pad, parser_data)
-  end
-
-  # set default padding if none was specified
-  defp parse_modifiers(<<format, _::binary>> = rest, width, nil, parser_data) do
-    parse_modifiers(rest, width, default_pad(format), parser_data)
-  end
-
-  # set default width if none was specified
-  defp parse_modifiers(<<format, _::binary>> = rest, nil, pad, parser_data) do
-    parse_modifiers(rest, default_width(format), pad, parser_data)
-  end
-
-  defp parse_modifiers(rest, width, pad, {datetime, format_options, acc}) do
-    format_modifiers(rest, width, pad, datetime, format_options, acc)
-  end
-
-  defp am_pm(hour, format_options) when hour > 11 do
-    format_options.am_pm_names.(:pm)
-  end
-
-  defp am_pm(hour, format_options) when hour <= 11 do
-    format_options.am_pm_names.(:am)
-  end
-
-  defp default_pad(format) when format in 'aAbBpPZ', do: ?\s
-  defp default_pad(_format), do: ?0
-
-  defp default_width(format) when format in 'dHImMSy', do: 2
-  defp default_width(?j), do: 3
-  defp default_width(format) when format in 'Yz', do: 4
-  defp default_width(_format), do: 0
-
-  # Literally just %
-  defp format_modifiers("%" <> rest, width, pad, datetime, format_options, acc) do
-    parse(rest, datetime, format_options, [pad_leading("%", width, pad) | acc])
-  end
-
-  # Abbreviated name of day
-  defp format_modifiers("a" <> rest, width, pad, datetime, format_options, acc) do
-    result =
-      datetime
-      |> Date.day_of_week()
-      |> format_options.abbreviated_day_of_week_names.()
-      |> pad_leading(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Full name of day
-  defp format_modifiers("A" <> rest, width, pad, datetime, format_options, acc) do
-    result =
-      datetime
-      |> Date.day_of_week()
-      |> format_options.day_of_week_names.()
-      |> pad_leading(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Abbreviated month name
-  defp format_modifiers("b" <> rest, width, pad, datetime, format_options, acc) do
-    result =
-      datetime.month
-      |> format_options.abbreviated_month_names.()
-      |> pad_leading(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Full month name
-  defp format_modifiers("B" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.month |> format_options.month_names.() |> pad_leading(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Preferred date+time representation
-  defp format_modifiers(
-         "c" <> _rest,
-         _width,
-         _pad,
-         _datetime,
-         %{preferred_datetime_invoked: true},
-         _acc
-       ) do
-    raise ArgumentError,
-          "tried to format preferred_datetime within another preferred_datetime format"
-  end
-
-  defp format_modifiers("c" <> rest, width, pad, datetime, format_options, acc) do
-    result =
-      format_options.preferred_datetime
-      |> parse(datetime, %{format_options | preferred_datetime_invoked: true}, [])
-      |> pad_preferred(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Day of the month
-  defp format_modifiers("d" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.day |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Microseconds
-  defp format_modifiers("f" <> rest, _width, _pad, datetime, format_options, acc) do
-    {microsecond, precision} = datetime.microsecond
-
-    result =
-      microsecond
-      |> Integer.to_string()
-      |> String.pad_leading(6, "0")
-      |> binary_part(0, max(precision, 1))
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Hour using a 24-hour clock
-  defp format_modifiers("H" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.hour |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Hour using a 12-hour clock
-  defp format_modifiers("I" <> rest, width, pad, datetime, format_options, acc) do
-    result = (rem(datetime.hour() + 23, 12) + 1) |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Day of the year
-  defp format_modifiers("j" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime |> Date.day_of_year() |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Month
-  defp format_modifiers("m" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.month |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Minute
-  defp format_modifiers("M" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.minute |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # "AM" or "PM" (noon is "PM", midnight as "AM")
-  defp format_modifiers("p" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.hour |> am_pm(format_options) |> String.upcase() |> pad_leading(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # "am" or "pm" (noon is "pm", midnight as "am")
-  defp format_modifiers("P" <> rest, width, pad, datetime, format_options, acc) do
-    result =
-      datetime.hour
-      |> am_pm(format_options)
-      |> String.downcase()
-      |> pad_leading(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Quarter
-  defp format_modifiers("q" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime |> Date.quarter_of_year() |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Second
-  defp format_modifiers("S" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.second |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Day of the week
-  defp format_modifiers("u" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime |> Date.day_of_week() |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Preferred date (without time) representation
-  defp format_modifiers(
-         "x" <> _rest,
-         _width,
-         _pad,
-         _datetime,
-         %{preferred_date_invoked: true},
-         _acc
-       ) do
-    raise ArgumentError,
-          "tried to format preferred_date within another preferred_date format"
-  end
-
-  defp format_modifiers("x" <> rest, width, pad, datetime, format_options, acc) do
-    result =
-      format_options.preferred_date
-      |> parse(datetime, %{format_options | preferred_date_invoked: true}, [])
-      |> pad_preferred(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Preferred time (without date) representation
-  defp format_modifiers(
-         "X" <> _rest,
-         _width,
-         _pad,
-         _datetime,
-         %{preferred_time_invoked: true},
-         _acc
-       ) do
-    raise ArgumentError,
-          "tried to format preferred_time within another preferred_time format"
-  end
-
-  defp format_modifiers("X" <> rest, width, pad, datetime, format_options, acc) do
-    result =
-      format_options.preferred_time
-      |> parse(datetime, %{format_options | preferred_time_invoked: true}, [])
-      |> pad_preferred(width, pad)
-
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Year as 2-digits
-  defp format_modifiers("y" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.year |> rem(100) |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # Year
-  defp format_modifiers("Y" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime.year |> Integer.to_string() |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  # +hhmm/-hhmm time zone offset from UTC (empty string if naive)
-  defp format_modifiers(
-         "z" <> rest,
-         width,
-         pad,
-         datetime = %{utc_offset: utc_offset, std_offset: std_offset},
-         format_options,
-         acc
-       ) do
-    absolute_offset = abs(utc_offset + std_offset)
-
-    offset_number =
-      Integer.to_string(div(absolute_offset, 3600) * 100 + rem(div(absolute_offset, 60), 60))
-
-    sign = if utc_offset + std_offset >= 0, do: "+", else: "-"
-    result = "#{sign}#{pad_leading(offset_number, width, pad)}"
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  defp format_modifiers("z" <> rest, _width, _pad, datetime, format_options, acc) do
-    parse(rest, datetime, format_options, ["" | acc])
-  end
-
-  # Time zone abbreviation (empty string if naive)
-  defp format_modifiers("Z" <> rest, width, pad, datetime, format_options, acc) do
-    result = datetime |> Map.get(:zone_abbr, "") |> pad_leading(width, pad)
-    parse(rest, datetime, format_options, [result | acc])
-  end
-
-  defp format_modifiers(rest, _width, _pad, _datetime, _format_options, _acc) do
-    {next, _rest} = String.next_grapheme(rest) || {"", ""}
-    raise ArgumentError, "invalid strftime format: %#{next}"
-  end
-
-  defp pad_preferred(result, width, pad) when length(result) < width do
-    pad_preferred([pad | result], width, pad)
-  end
-
-  defp pad_preferred(result, _width, _pad), do: result
-
-  defp pad_leading(string, count, padding) do
-    to_pad = count - byte_size(string)
-    if to_pad > 0, do: do_pad_leading(to_pad, padding, string), else: string
-  end
-
-  defp do_pad_leading(0, _, acc), do: acc
-
-  defp do_pad_leading(count, padding, acc),
-    do: do_pad_leading(count - 1, padding, [padding | acc])
-
-  defp options(user_options) do
-    default_options = %{
-      preferred_date: "%Y-%m-%d",
-      preferred_time: "%H:%M:%S",
-      preferred_datetime: "%Y-%m-%d %H:%M:%S",
-      am_pm_names: fn
-        :am -> "am"
-        :pm -> "pm"
-      end,
-      month_names: fn month ->
-        {"January", "February", "March", "April", "May", "June", "July", "August", "September",
-         "October", "November", "December"}
-        |> elem(month - 1)
-      end,
-      day_of_week_names: fn day_of_week ->
-        {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"}
-        |> elem(day_of_week - 1)
-      end,
-      abbreviated_month_names: fn month ->
-        {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}
-        |> elem(month - 1)
-      end,
-      abbreviated_day_of_week_names: fn day_of_week ->
-        {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"} |> elem(day_of_week - 1)
-      end,
-      preferred_datetime_invoked: false,
-      preferred_date_invoked: false,
-      preferred_time_invoked: false
-    }
-
-    Enum.reduce(user_options, default_options, fn {key, value}, acc ->
-      if Map.has_key?(acc, key) do
-        %{acc | key => value}
-      else
-        raise ArgumentError, "unknown option #{inspect(key)} given to Calendar.strftime/3"
-      end
-    end)
-  end
 end

lib/elixir/lib/calendar/date.ex

@@ -4,7 +4,7 @@ defmodule Date do
 
   The Date struct contains the fields year, month, day and calendar.
   New dates can be built with the `new/3` function or using the
-  `~D` (see `sigil_D/2`) sigil:
+  [`~D`](`Kernel.sigil_D/2`) sigil:
 
       iex> ~D[2000-01-01]
       ~D[2000-01-01]
@@ -25,18 +25,13 @@ defmodule Date do
 
   Developers should avoid creating the Date structs directly
   and instead rely on the functions provided by this module as well
-  as the ones in third-party calendar libraries.
+  as the ones in 3rd party calendar libraries.
 
   ## Comparing dates
 
   Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
   and based on the `Date` struct fields. For proper comparison between
-  dates, use the `compare/2` function. The existence of the `compare/2`
-  function in this module also allows using `Enum.min/2` and `Enum.max/2`
-  functions to get the minimum and maximum date of an `Enum`. For example:
-
-      iex>  Enum.min([~D[2017-03-31], ~D[2017-04-01]], Date)
-      ~D[2017-03-31]
+  dates, use the `compare/2` function.
 
   ## Using epochs
 
@@ -58,7 +53,7 @@ defmodule Date do
   @enforce_keys [:year, :month, :day]
   defstruct [:year, :month, :day, calendar: Calendar.ISO]
 
-  @type t :: %__MODULE__{
+  @type t :: %Date{
           year: Calendar.year(),
           month: Calendar.month(),
           day: Calendar.day(),
@@ -77,83 +72,39 @@ defmodule Date do
   ## Examples
 
       iex> Date.range(~D[1999-01-01], ~D[2000-01-01])
-      Date.range(~D[1999-01-01], ~D[2000-01-01])
+      #DateRange<~D[1999-01-01], ~D[2000-01-01]>
 
   A range of dates implements the `Enumerable` protocol, which means
   functions in the `Enum` module can be used to work with
   ranges:
 
       iex> range = Date.range(~D[2001-01-01], ~D[2002-01-01])
-      iex> range
-      Date.range(~D[2001-01-01], ~D[2002-01-01])
       iex> Enum.count(range)
       366
-      iex> ~D[2001-02-01] in range
+      iex> Enum.member?(range, ~D[2001-02-01])
       true
-      iex> Enum.take(range, 3)
-      [~D[2001-01-01], ~D[2001-01-02], ~D[2001-01-03]]
+      iex> Enum.reduce(range, 0, fn _date, acc -> acc - 1 end)
+      -366
 
   """
   @doc since: "1.5.0"
-  @spec range(Calendar.date(), Calendar.date()) :: Date.Range.t()
-  def range(%{calendar: calendar} = first, %{calendar: calendar} = last) do
+  @spec range(Date.t(), Date.t()) :: Date.Range.t()
+  def range(%Date{calendar: calendar} = first, %Date{calendar: calendar} = last) do
     {first_days, _} = to_iso_days(first)
     {last_days, _} = to_iso_days(last)
-    # TODO: Deprecate inferring a range with a step of -1 on Elixir v1.16
-    step = if first_days <= last_days, do: 1, else: -1
-    range(first, first_days, last, last_days, calendar, step)
-  end
 
-  def range(%{calendar: _, year: _, month: _, day: _}, %{calendar: _, year: _, month: _, day: _}) do
-    raise ArgumentError, "both dates must have matching calendars"
-  end
-
-  @doc """
-  Returns a range of dates with a step.
-
-  ## Examples
-
-      iex> range = Date.range(~D[2001-01-01], ~D[2002-01-01], 2)
-      iex> range
-      Date.range(~D[2001-01-01], ~D[2002-01-01], 2)
-      iex> Enum.count(range)
-      183
-      iex> ~D[2001-01-03] in range
-      true
-      iex> Enum.take(range, 3)
-      [~D[2001-01-01], ~D[2001-01-03], ~D[2001-01-05]]
-
-  """
-  @doc since: "1.12.0"
-  @spec range(Calendar.date(), Calendar.date(), step :: pos_integer | neg_integer) ::
-          Date.Range.t()
-  def range(%{calendar: calendar} = first, %{calendar: calendar} = last, step)
-      when is_integer(step) and step != 0 do
-    {first_days, _} = to_iso_days(first)
-    {last_days, _} = to_iso_days(last)
-    range(first, first_days, last, last_days, calendar, step)
-  end
-
-  def range(
-        %{calendar: _, year: _, month: _, day: _} = first,
-        %{calendar: _, year: _, month: _, day: _} = last,
-        step
-      ) do
-    raise ArgumentError,
-          "both dates must have matching calendar and the step must be a " <>
-            "non-zero integer, got: #{inspect(first)}, #{inspect(last)}, #{step}"
-  end
-
-  defp range(first, first_days, last, last_days, calendar, step) do
     %Date.Range{
-      first: %Date{calendar: calendar, year: first.year, month: first.month, day: first.day},
-      last: %Date{calendar: calendar, year: last.year, month: last.month, day: last.day},
+      first: first,
+      last: last,
       first_in_iso_days: first_days,
-      last_in_iso_days: last_days,
-      step: step
+      last_in_iso_days: last_days
     }
   end
 
+  def range(%Date{}, %Date{}) do
+    raise ArgumentError, "both dates must have matching calendars"
+  end
+
   @doc """
   Returns the current date in UTC.
 
@@ -273,33 +224,6 @@ defmodule Date do
     end
   end
 
-  @doc """
-  Builds a new ISO date.
-
-  Expects all values to be integers. Returns `date` if each
-  entry fits its appropriate range, raises if the date is invalid.
-
-  ## Examples
-
-      iex> Date.new!(2000, 1, 1)
-      ~D[2000-01-01]
-      iex> Date.new!(2000, 13, 1)
-      ** (ArgumentError) cannot build date, reason: :invalid_date
-      iex> Date.new!(2000, 2, 29)
-      ~D[2000-02-29]
-  """
-  @doc since: "1.11.0"
-  @spec new!(Calendar.year(), Calendar.month(), Calendar.day(), Calendar.calendar()) :: t
-  def new!(year, month, day, calendar \\ Calendar.ISO) do
-    case new(year, month, day, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError, "cannot build date, reason: #{inspect(reason)}"
-    end
-  end
-
   @doc """
   Converts the given date to a string according to its calendar.
 
@@ -322,9 +246,7 @@ defmodule Date do
 
   @doc """
   Parses the extended "Dates" format described by
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
-
-  The year parsed by this function is limited to four digits.
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   ## Examples
 
@@ -339,15 +261,36 @@ defmodule Date do
 
   """
   @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-  def from_iso8601(string, calendar \\ Calendar.ISO) do
-    with {:ok, {year, month, day}} <- Calendar.ISO.parse_date(string) do
-      convert(%Date{year: year, month: month, day: day}, calendar)
+  def from_iso8601(string, calendar \\ Calendar.ISO)
+
+  def from_iso8601(<<?-, rest::binary>>, calendar) do
+    with {:ok, %{year: year} = date} <- raw_from_iso8601(rest, calendar) do
+      {:ok, %{date | year: -year}}
+    end
+  end
+
+  def from_iso8601(<<rest::binary>>, calendar) do
+    raw_from_iso8601(rest, calendar)
+  end
+
+  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
+
+  defp raw_from_iso8601(string, calendar) do
+    with unquote(match_date) <- string,
+         true <- unquote(guard_date) do
+      {year, month, day} = unquote(read_date)
+
+      with {:ok, date} <- new(year, month, day, Calendar.ISO) do
+        convert(date, calendar)
+      end
+    else
+      _ -> {:error, :invalid_format}
     end
   end
 
   @doc """
   Parses the extended "Dates" format described by
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   Raises if the format is invalid.
 
@@ -372,7 +315,7 @@ defmodule Date do
 
   @doc """
   Converts the given `date` to
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   By default, `Date.to_iso8601/2` returns dates formatted in the "extended"
   format, for human readability. It also supports the "basic" format through passing the `:basic` option.
@@ -398,7 +341,7 @@ defmodule Date do
 
   def to_iso8601(%{calendar: Calendar.ISO} = date, format) when format in [:basic, :extended] do
     %{year: year, month: month, day: day} = date
-    Calendar.ISO.date_to_string(year, month, day, format)
+    Calendar.ISO.date_to_iso8601(year, month, day, format)
   end
 
   def to_iso8601(%{calendar: _} = date, format) when format in [:basic, :extended] do
@@ -474,45 +417,6 @@ defmodule Date do
     end
   end
 
-  @doc """
-  Converts a number of gregorian days to a `Date` struct.
-
-  ## Examples
-
-      iex> Date.from_gregorian_days(1)
-      ~D[0000-01-02]
-      iex> Date.from_gregorian_days(730_485)
-      ~D[2000-01-01]
-      iex> Date.from_gregorian_days(-1)
-      ~D[-0001-12-31]
-
-  """
-  @doc since: "1.11.0"
-  @spec from_gregorian_days(integer(), Calendar.calendar()) :: t
-  def from_gregorian_days(days, calendar \\ Calendar.ISO) when is_integer(days) do
-    from_iso_days({days, 0}, calendar)
-  end
-
-  @doc """
-  Converts a `date` struct to a number of gregorian days.
-
-  ## Examples
-
-      iex> Date.to_gregorian_days(~D[0000-01-02])
-      1
-      iex> Date.to_gregorian_days(~D[2000-01-01])
-      730_485
-      iex> Date.to_gregorian_days(~N[2000-01-01 00:00:00])
-      730_485
-
-  """
-  @doc since: "1.11.0"
-  @spec to_gregorian_days(Calendar.date()) :: integer()
-  def to_gregorian_days(date) do
-    {days, _} = to_iso_days(date)
-    days
-  end
-
   @doc """
   Compares two date structs.
 
@@ -549,8 +453,8 @@ defmodule Date do
     end
   end
 
-  def compare(%{calendar: calendar1} = date1, %{calendar: calendar2} = date2) do
-    if Calendar.compatible_calendars?(calendar1, calendar2) do
+  def compare(date1, date2) do
+    if Calendar.compatible_calendars?(date1.calendar, date2.calendar) do
       case {to_iso_days(date1), to_iso_days(date2)} do
         {first, second} when first > second -> :gt
         {first, second} when first < second -> :lt
@@ -561,7 +465,7 @@ defmodule Date do
       cannot compare #{inspect(date1)} with #{inspect(date2)}.
 
       This comparison would be ambiguous as their calendars have incompatible day rollover moments.
-      Specify an exact time of day (using DateTime) to resolve this ambiguity
+      Specify an exact time of day (using `DateTime`s) to resolve this ambiguity
       """
     end
   end
@@ -652,20 +556,9 @@ defmodule Date do
   """
   @doc since: "1.5.0"
   @spec add(Calendar.date(), integer()) :: t
-  def add(%{calendar: Calendar.ISO} = date, days) do
-    %{year: year, month: month, day: day} = date
-
-    {year, month, day} =
-      Calendar.ISO.date_to_iso_days(year, month, day)
-      |> Kernel.+(days)
-      |> Calendar.ISO.date_from_iso_days()
-
-    %Date{calendar: Calendar.ISO, year: year, month: month, day: day}
-  end
-
   def add(%{calendar: calendar} = date, days) do
-    {base_days, fraction} = to_iso_days(date)
-    from_iso_days({base_days + days, fraction}, calendar)
+    {iso_days, fraction} = to_iso_days(date)
+    from_iso_days({iso_days + days, fraction}, calendar)
   end
 
   @doc """
@@ -708,12 +601,11 @@ defmodule Date do
     end
   end
 
-  @doc false
-  def to_iso_days(%{calendar: Calendar.ISO, year: year, month: month, day: day}) do
+  defp to_iso_days(%{calendar: Calendar.ISO, year: year, month: month, day: day}) do
     {Calendar.ISO.date_to_iso_days(year, month, day), {0, 86_400_000_000}}
   end
 
-  def to_iso_days(%{calendar: calendar, year: year, month: month, day: day}) do
+  defp to_iso_days(%{calendar: calendar, year: year, month: month, day: day}) do
     calendar.naive_datetime_to_iso_days(year, month, day, 0, 0, 0, {0, 0})
   end
 
@@ -734,11 +626,6 @@ defmodule Date do
   calendar (the default), it is an integer from 1 to 7, where
   1 is Monday and 7 is Sunday.
 
-  An optional `starting_on` value may be supplied, which
-  configures the weekday the week starts on. The default value
-  for it is `:default`, which translates to `:monday` for the
-  built-in ISO calendar. Any other weekday may be given to.
-
   ## Examples
 
       iex> Date.day_of_week(~D[2016-10-31])
@@ -750,279 +637,13 @@ defmodule Date do
       iex> Date.day_of_week(~D[-0015-10-30])
       3
 
-      iex> Date.day_of_week(~D[2016-10-31], :sunday)
-      2
-      iex> Date.day_of_week(~D[2016-11-01], :sunday)
-      3
-      iex> Date.day_of_week(~N[2016-11-01 01:23:45], :sunday)
-      3
-      iex> Date.day_of_week(~D[-0015-10-30], :sunday)
-      4
-
   """
   @doc since: "1.4.0"
-  @spec day_of_week(Calendar.date(), starting_on :: :default | atom) :: Calendar.day_of_week()
-  def day_of_week(date, starting_on \\ :default)
+  @spec day_of_week(Calendar.date()) :: non_neg_integer()
+  def day_of_week(date)
 
-  def day_of_week(%{calendar: calendar, year: year, month: month, day: day}, starting_on) do
-    {day_of_week, _first, _last} = calendar.day_of_week(year, month, day, starting_on)
-    day_of_week
-  end
-
-  @doc """
-  Calculates a date that is the first day of the week for the given `date`.
-
-  If the day is already the first day of the week, it returns the
-  day itself. For the built-in ISO calendar, the week starts on Monday.
-  A weekday rather than `:default` can be given as `starting_on`.
-
-  ## Examples
-
-      iex> Date.beginning_of_week(~D[2020-07-11])
-      ~D[2020-07-06]
-      iex> Date.beginning_of_week(~D[2020-07-06])
-      ~D[2020-07-06]
-      iex> Date.beginning_of_week(~D[2020-07-11], :sunday)
-      ~D[2020-07-05]
-      iex> Date.beginning_of_week(~D[2020-07-11], :saturday)
-      ~D[2020-07-11]
-      iex> Date.beginning_of_week(~N[2020-07-11 01:23:45])
-      ~D[2020-07-06]
-
-  """
-  @doc since: "1.11.0"
-  @spec beginning_of_week(Calendar.date(), starting_on :: :default | atom) :: Date.t()
-  def beginning_of_week(date, starting_on \\ :default)
-
-  def beginning_of_week(%{calendar: Calendar.ISO} = date, starting_on) do
-    %{year: year, month: month, day: day} = date
-    iso_days = Calendar.ISO.date_to_iso_days(year, month, day)
-
-    {year, month, day} =
-      case Calendar.ISO.iso_days_to_day_of_week(iso_days, starting_on) do
-        1 ->
-          {year, month, day}
-
-        day_of_week ->
-          Calendar.ISO.date_from_iso_days(iso_days - day_of_week + 1)
-      end
-
-    %Date{calendar: Calendar.ISO, year: year, month: month, day: day}
-  end
-
-  def beginning_of_week(%{calendar: calendar} = date, starting_on) do
-    %{year: year, month: month, day: day} = date
-
-    case calendar.day_of_week(year, month, day, starting_on) do
-      {day_of_week, day_of_week, _} ->
-        %Date{calendar: calendar, year: year, month: month, day: day}
-
-      {day_of_week, first_day_of_week, _} ->
-        add(date, -(day_of_week - first_day_of_week))
-    end
-  end
-
-  @doc """
-  Calculates a date that is the last day of the week for the given `date`.
-
-  If the day is already the last day of the week, it returns the
-  day itself. For the built-in ISO calendar, the week ends on Sunday.
-  A weekday rather than `:default` can be given as `starting_on`.
-
-  ## Examples
-
-      iex> Date.end_of_week(~D[2020-07-11])
-      ~D[2020-07-12]
-      iex> Date.end_of_week(~D[2020-07-05])
-      ~D[2020-07-05]
-      iex> Date.end_of_week(~D[2020-07-06], :sunday)
-      ~D[2020-07-11]
-      iex> Date.end_of_week(~D[2020-07-06], :saturday)
-      ~D[2020-07-10]
-      iex> Date.end_of_week(~N[2020-07-11 01:23:45])
-      ~D[2020-07-12]
-
-  """
-  @doc since: "1.11.0"
-  @spec end_of_week(Calendar.date(), starting_on :: :default | atom) :: Date.t()
-  def end_of_week(date, starting_on \\ :default)
-
-  def end_of_week(%{calendar: Calendar.ISO} = date, starting_on) do
-    %{year: year, month: month, day: day} = date
-    iso_days = Calendar.ISO.date_to_iso_days(year, month, day)
-
-    {year, month, day} =
-      case Calendar.ISO.iso_days_to_day_of_week(iso_days, starting_on) do
-        7 ->
-          {year, month, day}
-
-        day_of_week ->
-          Calendar.ISO.date_from_iso_days(iso_days + 7 - day_of_week)
-      end
-
-    %Date{calendar: Calendar.ISO, year: year, month: month, day: day}
-  end
-
-  def end_of_week(%{calendar: calendar} = date, starting_on) do
-    %{year: year, month: month, day: day} = date
-
-    case calendar.day_of_week(year, month, day, starting_on) do
-      {day_of_week, _, day_of_week} ->
-        %Date{calendar: calendar, year: year, month: month, day: day}
-
-      {day_of_week, _, last_day_of_week} ->
-        add(date, last_day_of_week - day_of_week)
-    end
-  end
-
-  @doc """
-  Calculates the day of the year of a given `date`.
-
-  Returns the day of the year as an integer. For the ISO 8601
-  calendar (the default), it is an integer from 1 to 366.
-
-  ## Examples
-
-      iex> Date.day_of_year(~D[2016-01-01])
-      1
-      iex> Date.day_of_year(~D[2016-11-01])
-      306
-      iex> Date.day_of_year(~D[-0015-10-30])
-      303
-      iex> Date.day_of_year(~D[2004-12-31])
-      366
-
-  """
-  @doc since: "1.8.0"
-  @spec day_of_year(Calendar.date()) :: Calendar.day()
-  def day_of_year(date)
-
-  def day_of_year(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.day_of_year(year, month, day)
-  end
-
-  @doc """
-  Calculates the quarter of the year of a given `date`.
-
-  Returns the day of the year as an integer. For the ISO 8601
-  calendar (the default), it is an integer from 1 to 4.
-
-  ## Examples
-
-      iex> Date.quarter_of_year(~D[2016-10-31])
-      4
-      iex> Date.quarter_of_year(~D[2016-01-01])
-      1
-      iex> Date.quarter_of_year(~N[2016-04-01 01:23:45])
-      2
-      iex> Date.quarter_of_year(~D[-0015-09-30])
-      3
-
-  """
-  @doc since: "1.8.0"
-  @spec quarter_of_year(Calendar.date()) :: non_neg_integer()
-  def quarter_of_year(date)
-
-  def quarter_of_year(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.quarter_of_year(year, month, day)
-  end
-
-  @doc """
-  Calculates the year-of-era and era for a given
-  calendar year.
-
-  Returns a tuple `{year, era}` representing the
-  year within the era and the era number.
-
-  ## Examples
-
-      iex> Date.year_of_era(~D[0001-01-01])
-      {1, 1}
-      iex> Date.year_of_era(~D[0000-12-31])
-      {1, 0}
-      iex> Date.year_of_era(~D[-0001-01-01])
-      {2, 0}
-
-  """
-  @doc since: "1.8.0"
-  @spec year_of_era(Calendar.date()) :: {Calendar.year(), non_neg_integer()}
-  def year_of_era(date)
-
-  def year_of_era(%{calendar: calendar, year: year, month: month, day: day}) do
-    # TODO: Remove me on 1.17
-    # The behaviour implementation already warns on missing callback.
-    if function_exported?(calendar, :year_of_era, 3) do
-      calendar.year_of_era(year, month, day)
-    else
-      calendar.year_of_era(year)
-    end
-  end
-
-  @doc """
-  Calculates the day-of-era and era for a given
-  calendar `date`.
-
-  Returns a tuple `{day, era}` representing the
-  day within the era and the era number.
-
-  ## Examples
-
-      iex> Date.day_of_era(~D[0001-01-01])
-      {1, 1}
-
-      iex> Date.day_of_era(~D[0000-12-31])
-      {1, 0}
-
-  """
-  @doc since: "1.8.0"
-  @spec day_of_era(Calendar.date()) :: {Calendar.day(), non_neg_integer()}
-  def day_of_era(date)
-
-  def day_of_era(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.day_of_era(year, month, day)
-  end
-
-  @doc """
-  Calculates a date that is the first day of the month for the given `date`.
-
-  ## Examples
-
-      iex> Date.beginning_of_month(~D[2000-01-31])
-      ~D[2000-01-01]
-      iex> Date.beginning_of_month(~D[2000-01-01])
-      ~D[2000-01-01]
-      iex> Date.beginning_of_month(~N[2000-01-31 01:23:45])
-      ~D[2000-01-01]
-
-  """
-  @doc since: "1.11.0"
-  @spec beginning_of_month(Calendar.date()) :: t()
-  def beginning_of_month(date)
-
-  def beginning_of_month(%{year: year, month: month, calendar: calendar}) do
-    %Date{year: year, month: month, day: 1, calendar: calendar}
-  end
-
-  @doc """
-  Calculates a date that is the last day of the month for the given `date`.
-
-  ## Examples
-
-      iex> Date.end_of_month(~D[2000-01-01])
-      ~D[2000-01-31]
-      iex> Date.end_of_month(~D[2000-01-31])
-      ~D[2000-01-31]
-      iex> Date.end_of_month(~N[2000-01-01 01:23:45])
-      ~D[2000-01-31]
-
-  """
-  @doc since: "1.11.0"
-  @spec end_of_month(Calendar.date()) :: t()
-  def end_of_month(date)
-
-  def end_of_month(%{year: year, month: month, calendar: calendar} = date) do
-    day = Date.days_in_month(date)
-    %Date{year: year, month: month, day: day, calendar: calendar}
+  def day_of_week(%{calendar: calendar, year: year, month: month, day: day}) do
+    calendar.day_of_week(year, month, day)
   end
 
   ## Helpers
@@ -1034,11 +655,12 @@ defmodule Date do
   end
 
   defimpl Inspect do
-    def inspect(%{calendar: calendar, year: year, month: month, day: day}, _) do
-      "~D[" <> calendar.date_to_string(year, month, day) <> suffix(calendar) <> "]"
+    def inspect(%{calendar: Calendar.ISO, year: year, month: month, day: day}, _) do
+      "~D[" <> Calendar.ISO.date_to_string(year, month, day) <> "]"
     end
 
-    defp suffix(Calendar.ISO), do: ""
-    defp suffix(calendar), do: " " <> inspect(calendar)
+    def inspect(date, opts) do
+      Inspect.Any.inspect(date, opts)
+    end
   end
 end

lib/elixir/lib/calendar/date_range.ex

@@ -2,13 +2,12 @@ defmodule Date.Range do
   @moduledoc """
   Returns an inclusive range between dates.
 
-  Ranges must be created with the `Date.range/2` or `Date.range/3` function.
+  Ranges must be created with the `Date.range/2` function.
 
   The following fields are public:
 
     * `:first` - the initial date on the range
     * `:last` - the last date on the range
-    * `:step` - (since v1.12.0) the step
 
   The remaining fields are private and should not be accessed.
   """
@@ -16,134 +15,99 @@ defmodule Date.Range do
   @type t :: %__MODULE__{
           first: Date.t(),
           last: Date.t(),
-          first_in_iso_days: days(),
-          last_in_iso_days: days(),
-          step: pos_integer | neg_integer
+          first_in_iso_days: iso_days(),
+          last_in_iso_days: iso_days()
         }
 
-  @typep days() :: integer()
+  @typep iso_days() :: Calendar.iso_days()
 
-  @enforce_keys [:first, :last, :first_in_iso_days, :last_in_iso_days, :step]
-  defstruct [:first, :last, :first_in_iso_days, :last_in_iso_days, :step]
+  defstruct [:first, :last, :first_in_iso_days, :last_in_iso_days]
 
   defimpl Enumerable do
-    def member?(
-          %Date.Range{
-            first: %{calendar: calendar},
-            first_in_iso_days: first_days,
-            last_in_iso_days: last_days,
-            step: step
-          } = range,
-          %Date{calendar: calendar} = date
-        ) do
-      {days, _} = Date.to_iso_days(date)
+    def member?(%{first: %{calendar: calendar}} = range, %Date{calendar: calendar} = date) do
+      %{
+        first: first,
+        last: last,
+        first_in_iso_days: first_in_iso_days,
+        last_in_iso_days: last_in_iso_days
+      } = range
 
-      cond do
-        empty?(range) ->
-          {:ok, false}
+      %{year: first_year, month: first_month, day: first_day} = first
+      %{year: last_year, month: last_month, day: last_day} = last
+      %{year: year, month: month, day: day} = date
+      first = {first_year, first_month, first_day}
+      last = {last_year, last_month, last_day}
+      date = {year, month, day}
 
-        first_days <= last_days ->
-          {:ok, first_days <= days and days <= last_days and rem(days - first_days, step) == 0}
-
-        true ->
-          {:ok, last_days <= days and days <= first_days and rem(days - first_days, step) == 0}
+      if first_in_iso_days <= last_in_iso_days do
+        {:ok, date >= first and date <= last}
+      else
+        {:ok, date >= last and date <= first}
       end
     end
 
-    def member?(%Date.Range{step: _}, _) do
+    def member?(_, _) do
       {:ok, false}
     end
 
-    # TODO: Remove me on v2.0
-    def member?(
-          %{__struct__: Date.Range, first_in_iso_days: first_days, last_in_iso_days: last_days} =
-            date_range,
-          date
-        ) do
-      step = if first_days <= last_days, do: 1, else: -1
-      member?(Map.put(date_range, :step, step), date)
+    def count(%{first_in_iso_days: first, last_in_iso_days: last}) do
+      {:ok, abs(first - last) + 1}
     end
 
-    def count(range) do
-      {:ok, size(range)}
+    def slice(range) do
+      %{
+        first_in_iso_days: first,
+        last_in_iso_days: last,
+        first: %{calendar: calendar}
+      } = range
+
+      if first <= last do
+        {:ok, last - first + 1, &slice_asc(first + &1, &2, calendar)}
+      else
+        {:ok, first - last + 1, &slice_desc(first - &1, &2, calendar)}
+      end
     end
 
-    def slice(
-          %Date.Range{
-            first_in_iso_days: first,
-            first: %{calendar: calendar},
-            step: step
-          } = range
-        ) do
-      {:ok, size(range), &slice(first + &1 * step, step + &3 - 1, &2, calendar)}
+    defp slice_asc(current, 1, calendar), do: [date_from_iso_days(current, calendar)]
+
+    defp slice_asc(current, remaining, calendar) do
+      [date_from_iso_days(current, calendar) | slice_asc(current + 1, remaining - 1, calendar)]
     end
 
-    # TODO: Remove me on v2.0
-    def slice(
-          %{__struct__: Date.Range, first_in_iso_days: first_days, last_in_iso_days: last_days} =
-            date_range
-        ) do
-      step = if first_days <= last_days, do: 1, else: -1
-      slice(Map.put(date_range, :step, step))
+    defp slice_desc(current, 1, calendar), do: [date_from_iso_days(current, calendar)]
+
+    defp slice_desc(current, remaining, calendar) do
+      [date_from_iso_days(current, calendar) | slice_desc(current - 1, remaining - 1, calendar)]
     end
 
-    defp slice(current, _step, 1, calendar) do
-      [date_from_iso_days(current, calendar)]
+    def reduce(range, acc, fun) do
+      %{
+        first_in_iso_days: first_in_iso_days,
+        last_in_iso_days: last_in_iso_days,
+        first: %{calendar: calendar}
+      } = range
+
+      up? = first_in_iso_days <= last_in_iso_days
+      reduce(first_in_iso_days, last_in_iso_days, acc, fun, calendar, up?)
     end
 
-    defp slice(current, step, remaining, calendar) do
-      [
-        date_from_iso_days(current, calendar)
-        | slice(current + step, step, remaining - 1, calendar)
-      ]
-    end
-
-    def reduce(
-          %Date.Range{
-            first_in_iso_days: first_days,
-            last_in_iso_days: last_days,
-            first: %{calendar: calendar},
-            step: step
-          },
-          acc,
-          fun
-        ) do
-      reduce(first_days, last_days, acc, fun, step, calendar)
-    end
-
-    # TODO: Remove me on v2.0
-    def reduce(
-          %{__struct__: Date.Range, first_in_iso_days: first_days, last_in_iso_days: last_days} =
-            date_range,
-          acc,
-          fun
-        ) do
-      step = if first_days <= last_days, do: 1, else: -1
-      reduce(Map.put(date_range, :step, step), acc, fun)
-    end
-
-    defp reduce(_first_days, _last_days, {:halt, acc}, _fun, _step, _calendar) do
+    defp reduce(_x, _y, {:halt, acc}, _fun, _calendar, _up?) do
       {:halted, acc}
     end
 
-    defp reduce(first_days, last_days, {:suspend, acc}, fun, step, calendar) do
-      {:suspended, acc, &reduce(first_days, last_days, &1, fun, step, calendar)}
+    defp reduce(x, y, {:suspend, acc}, fun, calendar, up?) do
+      {:suspended, acc, &reduce(x, y, &1, fun, calendar, up?)}
     end
 
-    defp reduce(first_days, last_days, {:cont, acc}, fun, step, calendar)
-         when step > 0 and first_days <= last_days
-         when step < 0 and first_days >= last_days do
-      reduce(
-        first_days + step,
-        last_days,
-        fun.(date_from_iso_days(first_days, calendar), acc),
-        fun,
-        step,
-        calendar
-      )
+    defp reduce(x, y, {:cont, acc}, fun, calendar, up? = true) when x <= y do
+      reduce(x + 1, y, fun.(date_from_iso_days(x, calendar), acc), fun, calendar, up?)
     end
 
-    defp reduce(_, _, {:cont, acc}, _fun, _step, _calendar) do
+    defp reduce(x, y, {:cont, acc}, fun, calendar, up? = false) when x >= y do
+      reduce(x - 1, y, fun.(date_from_iso_days(x, calendar), acc), fun, calendar, up?)
+    end
+
+    defp reduce(_, _, {:cont, acc}, _fun, _calendar, _up) do
       {:done, acc}
     end
 
@@ -158,70 +122,11 @@ defmodule Date.Range do
 
       %Date{year: year, month: month, day: day, calendar: calendar}
     end
-
-    defp size(%Date.Range{first_in_iso_days: first_days, last_in_iso_days: last_days, step: step})
-         when step > 0 and first_days > last_days,
-         do: 0
-
-    defp size(%Date.Range{first_in_iso_days: first_days, last_in_iso_days: last_days, step: step})
-         when step < 0 and first_days < last_days,
-         do: 0
-
-    defp size(%Date.Range{first_in_iso_days: first_days, last_in_iso_days: last_days, step: step}),
-      do: abs(div(last_days - first_days, step)) + 1
-
-    # TODO: Remove me on v2.0
-    defp size(
-           %{__struct__: Date.Range, first_in_iso_days: first_days, last_in_iso_days: last_days} =
-             date_range
-         ) do
-      step = if first_days <= last_days, do: 1, else: -1
-      size(Map.put(date_range, :step, step))
-    end
-
-    defp empty?(%Date.Range{
-           first_in_iso_days: first_days,
-           last_in_iso_days: last_days,
-           step: step
-         })
-         when step > 0 and first_days > last_days,
-         do: true
-
-    defp empty?(%Date.Range{
-           first_in_iso_days: first_days,
-           last_in_iso_days: last_days,
-           step: step
-         })
-         when step < 0 and first_days < last_days,
-         do: true
-
-    defp empty?(%Date.Range{step: _}), do: false
-
-    # TODO: Remove me on v2.0
-    defp empty?(
-           %{__struct__: Date.Range, first_in_iso_days: first_days, last_in_iso_days: last_days} =
-             date_range
-         ) do
-      step = if first_days <= last_days, do: 1, else: -1
-      empty?(Map.put(date_range, :step, step))
-    end
   end
 
   defimpl Inspect do
-    import Kernel, except: [inspect: 2]
-
-    def inspect(%Date.Range{first: first, last: last, step: 1}, _) do
-      "Date.range(" <> inspect(first) <> ", " <> inspect(last) <> ")"
-    end
-
-    def inspect(%Date.Range{first: first, last: last, step: step}, _) do
-      "Date.range(" <> inspect(first) <> ", " <> inspect(last) <> ", #{step})"
-    end
-
-    # TODO: Remove me on v2.0
-    def inspect(%{__struct__: Date.Range, first: first, last: last} = date_range, opts) do
-      step = if first <= last, do: 1, else: -1
-      inspect(Map.put(date_range, :step, step), opts)
+    def inspect(%Date.Range{first: first, last: last}, _) do
+      "#DateRange<" <> inspect(first) <> ", " <> inspect(last) <> ">"
     end
   end
 end

lib/elixir/lib/calendar/naive_datetime.ex

@@ -5,7 +5,7 @@ defmodule NaiveDateTime do
   The NaiveDateTime struct contains the fields year, month, day, hour,
   minute, second, microsecond and calendar. New naive datetimes can be
   built with the `new/2` and `new/8` functions or using the
-  `~N` (see `sigil_N/2`) sigil:
+  [`~N`](`Kernel.sigil_N/2`) sigil:
 
       iex> ~N[2000-01-01 23:00:07]
       ~N[2000-01-01 23:00:07]
@@ -28,26 +28,25 @@ defmodule NaiveDateTime do
   `NaiveDateTime` is not validated against a time zone, such errors
   would go unnoticed.
 
+  The functions of this module work with the `NaiveDateTime` struct as well
+  as any struct that contains the same fields as the `NaiveDateTime` struct,
+  such as `DateTime`. Such functions expect
+  `t:Calendar.naive_datetime/0` in their typespecs (instead of `t:t/0`).
+
   Developers should avoid creating the NaiveDateTime structs directly
   and instead, rely on the functions provided by this module as well
-  as the ones in third-party calendar libraries.
+  as the ones in 3rd party calendar libraries.
 
   ## Comparing naive date times
 
   Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
   and based on the `NaiveDateTime` struct fields. For proper comparison
-  between naive datetimes, use the `compare/2` function. The existence of the
-  `compare/2` function in this module also allows using `Enum.min/2` and
-  `Enum.max/2` functions to get the minimum and maximum naive datetime of an
-  `Enum`. For example:
-
-      iex> Enum.min([~N[2020-01-01 23:00:07], ~N[2000-01-01 23:00:07]], NaiveDateTime)
-      ~N[2000-01-01 23:00:07]
+  between naive datetimes, use the `compare/2` function.
 
   ## Using epochs
 
-  The `add/3` and `diff/3` functions can be used for computing date
-  times or retrieving the number of seconds between instants.
+  The `add/3` and `diff/3` functions can be used for computing with
+  date times or retrieving the number of seconds between instants.
   For example, if there is an interest in computing the number of
   seconds from the Unix epoch (1970-01-01 00:00:00):
 
@@ -73,7 +72,7 @@ defmodule NaiveDateTime do
     calendar: Calendar.ISO
   ]
 
-  @type t :: %__MODULE__{
+  @type t :: %NaiveDateTime{
           year: Calendar.year(),
           month: Calendar.month(),
           day: Calendar.day(),
@@ -84,8 +83,6 @@ defmodule NaiveDateTime do
           microsecond: Calendar.microsecond()
         }
 
-  @seconds_per_day 24 * 60 * 60
-
   @doc """
   Returns the current naive datetime in UTC.
 
@@ -125,53 +122,6 @@ defmodule NaiveDateTime do
     |> DateTime.to_naive()
   end
 
-  @doc """
-  Returns the "local time" for the machine the Elixir program is running on.
-
-  WARNING: This function can cause insidious bugs. It depends on the time zone
-  configuration at run time. This can changed and be set to a time zone that has
-  daylight saving jumps (spring forward or fall back).
-
-  This function can be used to display what the time is right now for the time
-  zone configuration that the machine happens to have. An example would be a
-  desktop program displaying a clock to the user. For any other uses it is
-  probably a bad idea to use this function.
-
-  For most cases, use `DateTime.now/2` or `DateTime.utc_now/1` instead.
-
-  Does not include fractional seconds.
-
-  ## Examples
-
-      iex> naive_datetime = NaiveDateTime.local_now()
-      iex> naive_datetime.year >= 2019
-      true
-
-  """
-  @doc since: "1.10.0"
-  @spec local_now(Calendar.calendar()) :: t
-  def local_now(calendar \\ Calendar.ISO)
-
-  def local_now(Calendar.ISO) do
-    {{year, month, day}, {hour, minute, second}} = :erlang.localtime()
-    {:ok, ndt} = NaiveDateTime.new(year, month, day, hour, minute, second)
-    ndt
-  end
-
-  def local_now(calendar) do
-    naive_datetime = local_now()
-
-    case convert(naive_datetime, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, :incompatible_calendars} ->
-        raise ArgumentError,
-              ~s(cannot get "local now" in target calendar #{inspect(calendar)}, ) <>
-                "reason: cannot convert from Calendar.ISO to #{inspect(calendar)}."
-    end
-  end
-
   @doc """
   Builds a new ISO naive datetime.
 
@@ -196,11 +146,13 @@ defmodule NaiveDateTime do
       {:ok, ~N[2000-01-01 23:59:59.0]}
       iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 999_999)
       {:ok, ~N[2000-01-01 23:59:59.999999]}
+      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 60, 999_999)
+      {:ok, ~N[2000-01-01 23:59:60.999999]}
       iex> NaiveDateTime.new(2000, 1, 1, 24, 59, 59, 999_999)
       {:error, :invalid_time}
       iex> NaiveDateTime.new(2000, 1, 1, 23, 60, 59, 999_999)
       {:error, :invalid_time}
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 60, 999_999)
+      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 61, 999_999)
       {:error, :invalid_time}
       iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 1_000_000)
       {:error, :invalid_time}
@@ -216,7 +168,7 @@ defmodule NaiveDateTime do
           Calendar.hour(),
           Calendar.minute(),
           Calendar.second(),
-          Calendar.microsecond() | non_neg_integer,
+          Calendar.microsecond(),
           Calendar.calendar()
         ) :: {:ok, t} | {:error, atom}
   def new(year, month, day, hour, minute, second, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
@@ -250,61 +202,6 @@ defmodule NaiveDateTime do
     end
   end
 
-  @doc """
-  Builds a new ISO naive datetime.
-
-  Expects all values to be integers. Returns `naive_datetime`
-  if each entry fits its appropriate range, raises if
-  time or date is invalid.
-
-  ## Examples
-
-      iex> NaiveDateTime.new!(2000, 1, 1, 0, 0, 0)
-      ~N[2000-01-01 00:00:00]
-      iex> NaiveDateTime.new!(2000, 2, 29, 0, 0, 0)
-      ~N[2000-02-29 00:00:00]
-      iex> NaiveDateTime.new!(2000, 1, 1, 23, 59, 59, {0, 1})
-      ~N[2000-01-01 23:59:59.0]
-      iex> NaiveDateTime.new!(2000, 1, 1, 23, 59, 59, 999_999)
-      ~N[2000-01-01 23:59:59.999999]
-      iex> NaiveDateTime.new!(2000, 1, 1, 23, 59, 59, {0, 1}, Calendar.ISO)
-      ~N[2000-01-01 23:59:59.0]
-      iex> NaiveDateTime.new!(2000, 1, 1, 24, 59, 59, 999_999)
-      ** (ArgumentError) cannot build naive datetime, reason: :invalid_time
-
-  """
-  @doc since: "1.11.0"
-  @spec new!(
-          Calendar.year(),
-          Calendar.month(),
-          Calendar.day(),
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond() | non_neg_integer,
-          Calendar.calendar()
-        ) :: t
-  def new!(
-        year,
-        month,
-        day,
-        hour,
-        minute,
-        second,
-        microsecond \\ {0, 0},
-        calendar \\ Calendar.ISO
-      )
-
-  def new!(year, month, day, hour, minute, second, microsecond, calendar) do
-    case new(year, month, day, hour, minute, second, microsecond, calendar) do
-      {:ok, naive_datetime} ->
-        naive_datetime
-
-      {:error, reason} ->
-        raise ArgumentError, "cannot build naive datetime, reason: #{inspect(reason)}"
-    end
-  end
-
   @doc """
   Builds a naive datetime from date and time structs.
 
@@ -335,39 +232,16 @@ defmodule NaiveDateTime do
     {:ok, naive_datetime}
   end
 
-  @doc """
-  Builds a naive datetime from date and time structs.
-
-  ## Examples
-
-      iex> NaiveDateTime.new!(~D[2010-01-13], ~T[23:00:07.005])
-      ~N[2010-01-13 23:00:07.005]
-
-  """
-  @doc since: "1.11.0"
-  @spec new!(Date.t(), Time.t()) :: t
-  def new!(date, time)
-
-  def new!(%Date{calendar: calendar} = date, %Time{calendar: calendar} = time) do
-    {:ok, naive_datetime} = new(date, time)
-    naive_datetime
-  end
-
   @doc """
   Adds a specified amount of time to a `NaiveDateTime`.
 
-  Accepts an `amount_to_add` in any `unit`. `unit` can be `:day`,
-  `:hour`, `:minute`, `:second` or any subsecond precision from
-  `t:System.time_unit/0`. It defaults to `:second`. Negative values
-  will move backwards in time.
+  Accepts an `integer` in any `unit` available from `t:System.time_unit/0`.
+  Negative values will move backwards in time.
 
-  This function always consider the unit to be computed according
-  to the `Calendar.ISO`.
+  This operation is only possible if both calendars are convertible to `Calendar.ISO`.
 
   ## Examples
 
-  It uses seconds by default:
-
       # adds seconds by default
       iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2)
       ~N[2014-10-02 00:29:12]
@@ -376,85 +250,44 @@ defmodule NaiveDateTime do
       iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], -2)
       ~N[2014-10-02 00:29:08]
 
-  It can also work with subsecond precisions:
-
+      # can work with other units
       iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2_000, :millisecond)
       ~N[2014-10-02 00:29:12]
 
-  As well as days/hours/minutes:
-
-      iex> NaiveDateTime.add(~N[2015-02-28 00:29:10], 2, :day)
-      ~N[2015-03-02 00:29:10]
-      iex> NaiveDateTime.add(~N[2015-02-28 00:29:10], 36, :hour)
-      ~N[2015-03-01 12:29:10]
-      iex> NaiveDateTime.add(~N[2015-02-28 00:29:10], 60, :minute)
-      ~N[2015-02-28 01:29:10]
-
-  This operation keeps the precision of the naive date time:
-
+      # keeps the same precision
       iex> NaiveDateTime.add(~N[2014-10-02 00:29:10.021], 21, :second)
       ~N[2014-10-02 00:29:31.021]
 
-  And ignores any changes below the precision:
-
+      # changes below the precision will not be visible
       iex> hidden = NaiveDateTime.add(~N[2014-10-02 00:29:10], 21, :millisecond)
       iex> hidden.microsecond # ~N[2014-10-02 00:29:10]
       {21000, 0}
 
-  Operations on top of gregorian seconds or the Unix epoch are optimized:
-
       # from Gregorian seconds
       iex> NaiveDateTime.add(~N[0000-01-01 00:00:00], 63_579_428_950)
       ~N[2014-10-02 00:29:10]
 
-  Passing a `DateTime` automatically converts it to `NaiveDateTime`,
-  discarding the time zone information:
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> NaiveDateTime.add(dt, 21, :second)
-      ~N[2000-02-29 23:00:28]
-
   """
   @doc since: "1.4.0"
-  @spec add(Calendar.naive_datetime(), integer, :day | :hour | :minute | System.time_unit()) :: t
-  def add(naive_datetime, amount_to_add, unit \\ :second)
-
-  def add(naive_datetime, amount_to_add, :day) when is_integer(amount_to_add) do
-    add(naive_datetime, amount_to_add * 86400, :second)
-  end
-
-  def add(naive_datetime, amount_to_add, :hour) when is_integer(amount_to_add) do
-    add(naive_datetime, amount_to_add * 3600, :second)
-  end
-
-  def add(naive_datetime, amount_to_add, :minute) when is_integer(amount_to_add) do
-    add(naive_datetime, amount_to_add * 60, :second)
-  end
-
-  def add(
-        %{microsecond: {_, precision}, calendar: calendar} = naive_datetime,
-        amount_to_add,
-        unit
-      )
-      when is_integer(amount_to_add) do
+  @spec add(t, integer, System.time_unit()) :: t
+  def add(%NaiveDateTime{} = naive_datetime, integer, unit \\ :second)
+      when is_integer(integer) do
+    %{microsecond: {_, precision}, calendar: calendar} = naive_datetime
     ppd = System.convert_time_unit(86400, :second, unit)
 
     naive_datetime
     |> to_iso_days()
-    |> Calendar.ISO.add_day_fraction_to_iso_days(amount_to_add, ppd)
+    |> Calendar.ISO.add_day_fraction_to_iso_days(integer, ppd)
     |> from_iso_days(calendar, precision)
   end
 
   @doc """
   Subtracts `naive_datetime2` from `naive_datetime1`.
 
-  The answer can be returned in any `:day`, `:hour`, `:minute`, or any `unit`
-  available from `t:System.time_unit/0`. The unit is measured according to
-  `Calendar.ISO` and defaults to `:second`.
+  The answer can be returned in any `unit` available from `t:System.time_unit/0`.
 
-  Fractional results are not supported and are truncated.
+  This function returns the difference in seconds where seconds are measured
+  according to `Calendar.ISO`.
 
   ## Examples
 
@@ -462,59 +295,26 @@ defmodule NaiveDateTime do
       2
       iex> NaiveDateTime.diff(~N[2014-10-02 00:29:12], ~N[2014-10-02 00:29:10], :microsecond)
       2_000_000
-
-      iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10.042], ~N[2014-10-02 00:29:10.021])
-      0
       iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10.042], ~N[2014-10-02 00:29:10.021], :millisecond)
       21
-
       iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[2014-10-02 00:29:12])
       -2
       iex> NaiveDateTime.diff(~N[-0001-10-02 00:29:10], ~N[-0001-10-02 00:29:12])
       -2
 
-  It can also compute the difference in days, hours, or minutes:
-
-      iex> NaiveDateTime.diff(~N[2014-10-10 00:29:10], ~N[2014-10-02 00:29:10], :day)
-      8
-      iex> NaiveDateTime.diff(~N[2014-10-02 12:29:10], ~N[2014-10-02 00:29:10], :hour)
-      12
-      iex> NaiveDateTime.diff(~N[2014-10-02 00:39:10], ~N[2014-10-02 00:29:10], :minute)
-      10
-
-  But it also rounds incomplete days to zero:
-
-      iex> NaiveDateTime.diff(~N[2014-10-10 00:29:09], ~N[2014-10-02 00:29:10], :day)
-      7
+      # to Gregorian seconds
+      iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[0000-01-01 00:00:00])
+      63579428950
 
   """
   @doc since: "1.4.0"
-  @spec diff(
-          Calendar.naive_datetime(),
-          Calendar.naive_datetime(),
-          :day | :hour | :minute | System.time_unit()
-        ) :: integer
-
-  def diff(naive_datetime1, naive_datetime2, unit \\ :second)
-
-  def diff(naive_datetime1, naive_datetime2, :day) do
-    diff(naive_datetime1, naive_datetime2, :second) |> div(86400)
-  end
-
-  def diff(naive_datetime1, naive_datetime2, :hour) do
-    diff(naive_datetime1, naive_datetime2, :second) |> div(3600)
-  end
-
-  def diff(naive_datetime1, naive_datetime2, :minute) do
-    diff(naive_datetime1, naive_datetime2, :second) |> div(60)
-  end
-
+  @spec diff(t, t, System.time_unit()) :: integer
   def diff(
-        %{calendar: calendar1} = naive_datetime1,
-        %{calendar: calendar2} = naive_datetime2,
-        unit
+        %NaiveDateTime{} = naive_datetime1,
+        %NaiveDateTime{} = naive_datetime2,
+        unit \\ :second
       ) do
-    if not Calendar.compatible_calendars?(calendar1, calendar2) do
+    if not Calendar.compatible_calendars?(naive_datetime1.calendar, naive_datetime2.calendar) do
       raise ArgumentError,
             "cannot calculate the difference between #{inspect(naive_datetime1)} and " <>
               "#{inspect(naive_datetime2)} because their calendars are not compatible " <>
@@ -530,9 +330,6 @@ defmodule NaiveDateTime do
   Returns the given naive datetime with the microsecond field truncated to the
   given precision (`:microsecond`, `:millisecond` or `:second`).
 
-  The given naive datetime is returned unchanged if it already has lower precision
-  than the given precision.
-
   ## Examples
 
       iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :microsecond)
@@ -551,31 +348,6 @@ defmodule NaiveDateTime do
     %{naive_datetime | microsecond: Calendar.truncate(microsecond, precision)}
   end
 
-  def truncate(
-        %{
-          calendar: calendar,
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        },
-        precision
-      ) do
-    %NaiveDateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: Calendar.truncate(microsecond, precision)
-    }
-  end
-
   @doc """
   Converts a `NaiveDateTime` into a `Date`.
 
@@ -588,17 +360,8 @@ defmodule NaiveDateTime do
       ~D[2002-01-13]
 
   """
-  @spec to_date(Calendar.naive_datetime()) :: Date.t()
-  def to_date(%{
-        year: year,
-        month: month,
-        day: day,
-        calendar: calendar,
-        hour: _,
-        minute: _,
-        second: _,
-        microsecond: _
-      }) do
+  @spec to_date(t) :: Date.t()
+  def to_date(%NaiveDateTime{year: year, month: month, day: day, calendar: calendar}) do
     %Date{year: year, month: month, day: day, calendar: calendar}
   end
 
@@ -614,17 +377,16 @@ defmodule NaiveDateTime do
       ~T[23:00:07]
 
   """
-  @spec to_time(Calendar.naive_datetime()) :: Time.t()
-  def to_time(%{
-        year: _,
-        month: _,
-        day: _,
-        calendar: calendar,
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond
-      }) do
+  @spec to_time(t) :: Time.t()
+  def to_time(%NaiveDateTime{} = naive_datetime) do
+    %{
+      hour: hour,
+      minute: minute,
+      second: second,
+      microsecond: microsecond,
+      calendar: calendar
+    } = naive_datetime
+
     %Time{
       hour: hour,
       minute: minute,
@@ -673,7 +435,7 @@ defmodule NaiveDateTime do
 
   @doc """
   Parses the extended "Date and time of day" format described by
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   Time zone offset may be included in the string but they will be
   simply discarded as such information is not included in naive date
@@ -682,7 +444,10 @@ defmodule NaiveDateTime do
   As specified in the standard, the separator "T" may be omitted if
   desired as there is no ambiguity within this function.
 
-  Note leap seconds are not supported by the built-in Calendar.ISO.
+  Time representations with reduced accuracy are not supported.
+
+  Note that while ISO 8601 allows datetimes to specify 24:00:00 as the
+  zero hour of the next day, this notation is not supported by Elixir.
 
   ## Examples
 
@@ -728,27 +493,41 @@ defmodule NaiveDateTime do
 
   """
   @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-  def from_iso8601(string, calendar \\ Calendar.ISO) do
-    with {:ok, {year, month, day, hour, minute, second, microsecond}} <-
-           Calendar.ISO.parse_naive_datetime(string) do
-      convert(
-        %NaiveDateTime{
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        },
-        calendar
-      )
+  def from_iso8601(string, calendar \\ Calendar.ISO)
+
+  def from_iso8601(<<?-, rest::binary>>, calendar) do
+    with {:ok, %{year: year} = naive_datetime} <- raw_from_iso8601(rest, calendar) do
+      {:ok, %{naive_datetime | year: -year}}
+    end
+  end
+
+  def from_iso8601(<<rest::binary>>, calendar) do
+    raw_from_iso8601(rest, calendar)
+  end
+
+  @sep [?\s, ?T]
+  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
+  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
+
+  defp raw_from_iso8601(string, calendar) do
+    with <<unquote(match_date), sep, unquote(match_time), rest::binary>> <- string,
+         true <- unquote(guard_date) and sep in @sep and unquote(guard_time),
+         {microsec, rest} <- Calendar.ISO.parse_microsecond(rest),
+         {_offset, ""} <- Calendar.ISO.parse_offset(rest) do
+      {year, month, day} = unquote(read_date)
+      {hour, min, sec} = unquote(read_time)
+
+      with {:ok, utc_date} <- new(year, month, day, hour, min, sec, microsec, Calendar.ISO) do
+        convert(utc_date, calendar)
+      end
+    else
+      _ -> {:error, :invalid_format}
     end
   end
 
   @doc """
   Parses the extended "Date and time of day" format described by
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   Raises if the format is invalid.
 
@@ -762,7 +541,7 @@ defmodule NaiveDateTime do
       ** (ArgumentError) cannot parse "2015-01-23P23:50:07" as naive datetime, reason: :invalid_format
 
   """
-  @spec from_iso8601!(String.t(), Calendar.calendar()) :: t
+  @spec from_iso8601!(String.t(), Calendar.calendar()) :: t | no_return
   def from_iso8601!(string, calendar \\ Calendar.ISO) do
     case from_iso8601(string, calendar) do
       {:ok, value} ->
@@ -776,7 +555,7 @@ defmodule NaiveDateTime do
 
   @doc """
   Converts the given naive datetime to
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   By default, `NaiveDateTime.to_iso8601/2` returns naive datetimes formatted in the "extended"
   format, for human readability. It also supports the "basic" format through passing the `:basic` option.
@@ -820,8 +599,16 @@ defmodule NaiveDateTime do
       microsecond: microsecond
     } = naive_datetime
 
-    Calendar.ISO.date_to_string(year, month, day, format) <>
-      "T" <> Calendar.ISO.time_to_string(hour, minute, second, microsecond, format)
+    Calendar.ISO.naive_datetime_to_iso8601(
+      year,
+      month,
+      day,
+      hour,
+      minute,
+      second,
+      microsecond,
+      format
+    )
   end
 
   def to_iso8601(%{calendar: _} = naive_datetime, format) when format in [:basic, :extended] do
@@ -844,8 +631,8 @@ defmodule NaiveDateTime do
       iex> NaiveDateTime.to_erl(~N[2000-01-01 13:30:15])
       {{2000, 1, 1}, {13, 30, 15}}
 
-  This function can also be used to convert a DateTime to an Erlang
-  datetime tuple without the time zone information:
+  This function can also be used to convert a DateTime to a erl format
+  without the time zone information:
 
       iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
       ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
@@ -884,8 +671,8 @@ defmodule NaiveDateTime do
   def from_erl(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
 
   def from_erl({{year, month, day}, {hour, minute, second}}, microsecond, calendar) do
-    with {:ok, iso_naive_dt} <- new(year, month, day, hour, minute, second, microsecond),
-         do: convert(iso_naive_dt, calendar)
+    with {:ok, utc_date} <- new(year, month, day, hour, minute, second, microsecond),
+         do: convert(utc_date, calendar)
   end
 
   @doc """
@@ -904,7 +691,8 @@ defmodule NaiveDateTime do
       ** (ArgumentError) cannot convert {{2000, 13, 1}, {13, 30, 15}} to naive datetime, reason: :invalid_date
 
   """
-  @spec from_erl!(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) :: t
+  @spec from_erl!(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) ::
+          t | no_return
   def from_erl!(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO) do
     case from_erl(tuple, microsecond, calendar) do
       {:ok, value} ->
@@ -916,82 +704,6 @@ defmodule NaiveDateTime do
     end
   end
 
-  @doc """
-  Converts a number of gregorian seconds to a `NaiveDateTime` struct.
-
-  ## Examples
-
-      iex> NaiveDateTime.from_gregorian_seconds(1)
-      ~N[0000-01-01 00:00:01]
-      iex> NaiveDateTime.from_gregorian_seconds(63_755_511_991, {5000, 3})
-      ~N[2020-05-01 00:26:31.005]
-      iex> NaiveDateTime.from_gregorian_seconds(-1)
-      ~N[-0001-12-31 23:59:59]
-
-  """
-  @doc since: "1.11.0"
-  @spec from_gregorian_seconds(integer(), Calendar.microsecond(), Calendar.calendar()) :: t
-  def from_gregorian_seconds(
-        seconds,
-        {microsecond, precision} \\ {0, 0},
-        calendar \\ Calendar.ISO
-      )
-      when is_integer(seconds) do
-    iso_days = Calendar.ISO.gregorian_seconds_to_iso_days(seconds, microsecond)
-
-    {year, month, day, hour, minute, second, {microsecond, _}} =
-      calendar.naive_datetime_from_iso_days(iso_days)
-
-    %NaiveDateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: {microsecond, precision}
-    }
-  end
-
-  @doc """
-  Converts a `NaiveDateTime` struct to a number of gregorian seconds and microseconds.
-
-  ## Examples
-
-      iex> NaiveDateTime.to_gregorian_seconds(~N[0000-01-01 00:00:01])
-      {1, 0}
-      iex> NaiveDateTime.to_gregorian_seconds(~N[2020-05-01 00:26:31.005])
-      {63_755_511_991, 5000}
-
-  """
-  @doc since: "1.11.0"
-  @spec to_gregorian_seconds(Calendar.naive_datetime()) :: {integer(), non_neg_integer()}
-  def to_gregorian_seconds(%{
-        calendar: calendar,
-        year: year,
-        month: month,
-        day: day,
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: {microsecond, precision}
-      }) do
-    {days, day_fraction} =
-      calendar.naive_datetime_to_iso_days(
-        year,
-        month,
-        day,
-        hour,
-        minute,
-        second,
-        {microsecond, precision}
-      )
-
-    seconds_in_day = seconds_from_day_fraction(day_fraction)
-    {days * @seconds_per_day + seconds_in_day, microsecond}
-  end
-
   @doc """
   Compares two `NaiveDateTime` structs.
 
@@ -1136,12 +848,6 @@ defmodule NaiveDateTime do
 
   ## Helpers
 
-  defp seconds_from_day_fraction({parts_in_day, @seconds_per_day}),
-    do: parts_in_day
-
-  defp seconds_from_day_fraction({parts_in_day, parts_per_day}),
-    do: div(parts_in_day * @seconds_per_day, parts_per_day)
-
   # Keep it multiline for proper function clause errors.
   defp to_iso_days(%{
          calendar: calendar,
@@ -1190,7 +896,7 @@ defmodule NaiveDateTime do
   end
 
   defimpl Inspect do
-    def inspect(naive_datetime, _) do
+    def inspect(%{calendar: Calendar.ISO} = naive_datetime, _) do
       %{
         year: year,
         month: month,
@@ -1198,17 +904,17 @@ defmodule NaiveDateTime do
         hour: hour,
         minute: minute,
         second: second,
-        microsecond: microsecond,
-        calendar: calendar
+        microsecond: microsecond
       } = naive_datetime
 
       formatted =
-        calendar.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
+        Calendar.ISO.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
 
-      "~N[" <> formatted <> suffix(calendar) <> "]"
+      "~N[" <> formatted <> "]"
     end
 
-    defp suffix(Calendar.ISO), do: ""
-    defp suffix(calendar), do: " " <> inspect(calendar)
+    def inspect(naive, opts) do
+      Inspect.Any.inspect(naive, opts)
+    end
   end
 end

lib/elixir/lib/calendar/time.ex

@@ -4,7 +4,7 @@ defmodule Time do
 
   The Time struct contains the fields hour, minute, second and microseconds.
   New times can be built with the `new/4` function or using the
-  `~T` (see `sigil_T/2`) sigil:
+  [`~T`](`Kernel.sigil_T/2`) sigil:
 
       iex> ~T[23:00:07.001]
       ~T[23:00:07.001]
@@ -25,24 +25,19 @@ defmodule Time do
 
   Developers should avoid creating the Time structs directly
   and instead rely on the functions provided by this module as well
-  as the ones in third-party calendar libraries.
+  as the ones in 3rd party calendar libraries.
 
   ## Comparing times
 
   Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
   and based on the `Time` struct fields. For proper comparison between
-  times, use the `compare/2` function. The existence of the `compare/2`
-  function in this module also allows using `Enum.min/2` and `Enum.max/2`
-  functions to get the minimum and maximum time of an `Enum`. For example:
-
-      iex> Enum.min([~T[23:00:07.001], ~T[10:00:07.001]], Time)
-      ~T[10:00:07.001]
+  times, use the `compare/2` function.
   """
 
   @enforce_keys [:hour, :minute, :second]
   defstruct [:hour, :minute, :second, microsecond: {0, 0}, calendar: Calendar.ISO]
 
-  @type t :: %__MODULE__{
+  @type t :: %Time{
           hour: Calendar.hour(),
           minute: Calendar.minute(),
           second: Calendar.second(),
@@ -50,9 +45,6 @@ defmodule Time do
           calendar: Calendar.calendar()
         }
 
-  @parts_per_day 86_400_000_000
-  @seconds_per_day 24 * 60 * 60
-
   @doc """
   Returns the current time in UTC.
 
@@ -86,10 +78,9 @@ defmodule Time do
   Expects all values to be integers. Returns `{:ok, time}` if each
   entry fits its appropriate range, returns `{:error, reason}` otherwise.
 
-  Microseconds can also be given with a precision, which must be an
-  integer between 0 and 6.
-
-  The built-in calendar does not support leap seconds.
+  Note a time may have 60 seconds in case of leap seconds. Microseconds
+  can also be given with a precision, which must be an integer between
+  0 and 6.
 
   ## Examples
 
@@ -97,12 +88,18 @@ defmodule Time do
       {:ok, ~T[00:00:00.000000]}
       iex> Time.new(23, 59, 59, 999_999)
       {:ok, ~T[23:59:59.999999]}
+      iex> Time.new(23, 59, 60, 999_999)
+      {:ok, ~T[23:59:60.999999]}
+
+      # Time with microseconds and their precision
+      iex> Time.new(23, 59, 60, {10_000, 2})
+      {:ok, ~T[23:59:60.01]}
 
       iex> Time.new(24, 59, 59, 999_999)
       {:error, :invalid_time}
       iex> Time.new(23, 60, 59, 999_999)
       {:error, :invalid_time}
-      iex> Time.new(23, 59, 60, 999_999)
+      iex> Time.new(23, 59, 61, 999_999)
       {:error, :invalid_time}
       iex> Time.new(23, 59, 59, 1_000_000)
       {:error, :invalid_time}
@@ -116,7 +113,7 @@ defmodule Time do
           Calendar.hour(),
           Calendar.minute(),
           Calendar.second(),
-          Calendar.microsecond() | non_neg_integer,
+          Calendar.microsecond() | integer,
           Calendar.calendar()
         ) :: {:ok, t} | {:error, atom}
   def new(hour, minute, second, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
@@ -145,44 +142,6 @@ defmodule Time do
     end
   end
 
-  @doc """
-  Builds a new time.
-
-  Expects all values to be integers. Returns `time` if each
-  entry fits its appropriate range, raises if the time is invalid.
-
-  Microseconds can also be given with a precision, which must be an
-  integer between 0 and 6.
-
-  The built-in calendar does not support leap seconds.
-
-  ## Examples
-
-      iex> Time.new!(0, 0, 0, 0)
-      ~T[00:00:00.000000]
-      iex> Time.new!(23, 59, 59, 999_999)
-      ~T[23:59:59.999999]
-      iex> Time.new!(24, 59, 59, 999_999)
-      ** (ArgumentError) cannot build time, reason: :invalid_time
-  """
-  @doc since: "1.11.0"
-  @spec new!(
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond() | non_neg_integer,
-          Calendar.calendar()
-        ) :: t
-  def new!(hour, minute, second, microsecond \\ {0, 0}, calendar \\ Calendar.ISO) do
-    case new(hour, minute, second, microsecond, calendar) do
-      {:ok, time} ->
-        time
-
-      {:error, reason} ->
-        raise ArgumentError, "cannot build time, reason: #{inspect(reason)}"
-    end
-  end
-
   @doc """
   Converts the given `time` to a string.
 
@@ -216,7 +175,7 @@ defmodule Time do
 
   @doc """
   Parses the extended "Local time" format described by
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   Time zone offset may be included in the string but they will be
   simply discarded as such information is not included in times.
@@ -224,6 +183,11 @@ defmodule Time do
   As specified in the standard, the separator "T" may be omitted if
   desired as there is no ambiguity within this function.
 
+  Time representations with reduced accuracy are not supported.
+
+  Note that while ISO 8601 allows times to specify 24:00:00 as the
+  zero hour of the next day, this notation is not supported by Elixir.
+
   ## Examples
 
       iex> Time.from_iso8601("23:50:07")
@@ -251,18 +215,36 @@ defmodule Time do
 
   """
   @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-  def from_iso8601(string, calendar \\ Calendar.ISO) do
-    with {:ok, {hour, minute, second, microsecond}} <- Calendar.ISO.parse_time(string) do
-      convert(
-        %Time{hour: hour, minute: minute, second: second, microsecond: microsecond},
-        calendar
-      )
+  def from_iso8601(string, calendar \\ Calendar.ISO)
+
+  def from_iso8601(<<?T, rest::binary>>, calendar) do
+    raw_from_iso8601(rest, calendar)
+  end
+
+  def from_iso8601(<<rest::binary>>, calendar) do
+    raw_from_iso8601(rest, calendar)
+  end
+
+  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
+
+  defp raw_from_iso8601(string, calendar) do
+    with <<unquote(match_time), rest::binary>> <- string,
+         true <- unquote(guard_time),
+         {microsec, rest} <- Calendar.ISO.parse_microsecond(rest),
+         {_offset, ""} <- Calendar.ISO.parse_offset(rest) do
+      {hour, min, sec} = unquote(read_time)
+
+      with {:ok, utc_time} <- new(hour, min, sec, microsec, Calendar.ISO) do
+        convert(utc_time, calendar)
+      end
+    else
+      _ -> {:error, :invalid_format}
     end
   end
 
   @doc """
   Parses the extended "Local time" format described by
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   Raises if the format is invalid.
 
@@ -289,7 +271,7 @@ defmodule Time do
 
   @doc """
   Converts the given time to
-  [ISO 8601:2019](https://en.wikipedia.org/wiki/ISO_8601).
+  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
   By default, `Time.to_iso8601/2` returns times formatted in the "extended"
   format, for human readability. It also supports the "basic" format through
@@ -321,7 +303,7 @@ defmodule Time do
       microsecond: microsecond
     } = time
 
-    Calendar.ISO.time_to_string(hour, minute, second, microsecond, format)
+    Calendar.ISO.time_to_iso8601(hour, minute, second, microsecond, format)
   end
 
   def to_iso8601(%{calendar: _} = time, format) when format in [:extended, :basic] do
@@ -397,72 +379,10 @@ defmodule Time do
   end
 
   @doc """
-  Converts a number of seconds after midnight to a `Time` struct.
+  Adds the `number` of `unit`s to the given `time`.
 
-  ## Examples
-
-      iex> Time.from_seconds_after_midnight(10_000)
-      ~T[02:46:40]
-      iex> Time.from_seconds_after_midnight(30_000, {5000, 3})
-      ~T[08:20:00.005]
-      iex> Time.from_seconds_after_midnight(-1)
-      ~T[23:59:59]
-      iex> Time.from_seconds_after_midnight(100_000)
-      ~T[03:46:40]
-
-  """
-  @doc since: "1.11.0"
-  @spec from_seconds_after_midnight(
-          integer(),
-          Calendar.microsecond(),
-          Calendar.calendar()
-        ) :: t
-  def from_seconds_after_midnight(seconds, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
-      when is_integer(seconds) do
-    seconds_in_day = Integer.mod(seconds, @seconds_per_day)
-
-    {hour, minute, second, {_, _}} =
-      calendar.time_from_day_fraction({seconds_in_day, @seconds_per_day})
-
-    %Time{
-      calendar: calendar,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    }
-  end
-
-  @doc """
-  Converts a `Time` struct to a number of seconds after midnight.
-
-  The returned value is a two-element tuple with the number of seconds and microseconds.
-
-  ## Examples
-
-      iex> Time.to_seconds_after_midnight(~T[23:30:15])
-      {84615, 0}
-      iex> Time.to_seconds_after_midnight(~N[2010-04-17 23:30:15.999])
-      {84615, 999000}
-
-  """
-  @doc since: "1.11.0"
-  @spec to_seconds_after_midnight(Calendar.time()) :: {integer(), non_neg_integer()}
-  def to_seconds_after_midnight(%{microsecond: {microsecond, _precision}} = time) do
-    iso_days = {0, to_day_fraction(time)}
-    {Calendar.ISO.iso_days_to_unit(iso_days, :second), microsecond}
-  end
-
-  @doc """
-  Adds the `amount_to_add` of `unit`s to the given `time`.
-
-  Accepts an `amount_to_add` in any `unit`. `unit` can be `:day`,
-  `:hour`, `:minute`, `:second` or any subsecond precision from
-  `t:System.time_unit/0`. It defaults to `:second`. Negative values
-  will move backwards in time.
-
-  This function always consider the unit to be computed according
-  to the `Calendar.ISO`.
+  This function accepts the `number` measured according to `Calendar.ISO`.
+  The time is returned in the same calendar as it was given in.
 
   Note the result value represents the time of day, meaning that it is cyclic,
   for instance, it will never go over 24 hours for the ISO calendar.
@@ -470,75 +390,37 @@ defmodule Time do
   ## Examples
 
       iex> Time.add(~T[10:00:00], 27000)
-      ~T[17:30:00]
+      ~T[17:30:00.000000]
       iex> Time.add(~T[11:00:00.005], 2400)
-      ~T[11:40:00.005]
-      iex> Time.add(~T[00:00:00.000], 86_399_999, :millisecond)
-      ~T[23:59:59.999]
-
-  Negative values are allowed:
-
-      iex> Time.add(~T[23:00:00], -60)
-      ~T[22:59:00]
-
-  Note that the time is cyclic:
-
+      ~T[11:40:00.005000]
+      iex> Time.add(~T[00:00:00], 86_399_999, :millisecond)
+      ~T[23:59:59.999000]
       iex> Time.add(~T[17:10:05], 86400)
-      ~T[17:10:05]
-
-  Hours and minutes are also supported:
-
-      iex> Time.add(~T[17:10:05], 2, :hour)
-      ~T[19:10:05]
-      iex> Time.add(~T[17:10:05], 30, :minute)
-      ~T[17:40:05]
+      ~T[17:10:05.000000]
+      iex> Time.add(~T[23:00:00], -60)
+      ~T[22:59:00.000000]
 
   """
   @doc since: "1.6.0"
-  @spec add(Calendar.time(), integer, :hour | :minute | System.time_unit()) :: t
-  def add(time, amount_to_add, unit \\ :second)
+  @spec add(Calendar.time(), integer, System.time_unit()) :: t
+  def add(%{calendar: calendar} = time, number, unit \\ :second) when is_integer(number) do
+    number = System.convert_time_unit(number, unit, :microsecond)
+    iso_days = {0, to_day_fraction(time)}
+    total = Calendar.ISO.iso_days_to_unit(iso_days, :microsecond) + number
+    iso_ppd = 86_400_000_000
+    parts = Integer.mod(total, iso_ppd)
 
-  def add(time, amount_to_add, :hour) when is_integer(amount_to_add) do
-    add(time, amount_to_add * 3600, :second)
-  end
-
-  def add(time, amount_to_add, :minute) when is_integer(amount_to_add) do
-    add(time, amount_to_add * 60, :second)
-  end
-
-  def add(%{calendar: calendar, microsecond: {_, precision}} = time, amount_to_add, unit)
-      when is_integer(amount_to_add) do
-    amount_to_add = System.convert_time_unit(amount_to_add, unit, :microsecond)
-    total = time_to_microseconds(time) + amount_to_add
-    parts = Integer.mod(total, @parts_per_day)
-
-    {hour, minute, second, {microsecond, _}} =
-      calendar.time_from_day_fraction({parts, @parts_per_day})
+    {hour, minute, second, microsecond} = calendar.time_from_day_fraction({parts, iso_ppd})
 
     %Time{
       hour: hour,
       minute: minute,
       second: second,
-      microsecond: {microsecond, precision},
+      microsecond: microsecond,
       calendar: calendar
     }
   end
 
-  defp time_to_microseconds(%{
-         calendar: Calendar.ISO,
-         hour: 0,
-         minute: 0,
-         second: 0,
-         microsecond: {0, _}
-       }) do
-    0
-  end
-
-  defp time_to_microseconds(time) do
-    iso_days = {0, to_day_fraction(time)}
-    Calendar.ISO.iso_days_to_unit(iso_days, :microsecond)
-  end
-
   @doc """
   Compares two time structs.
 
@@ -682,16 +564,16 @@ defmodule Time do
 
   As with the `compare/2` function both `Time` structs and other structures
   containing time can be used. If for instance a `NaiveDateTime` or `DateTime`
-  is passed, only the hour, minute, second, and microsecond is considered. Any
+  is passed, only the hour, month, second, and microsecond is considered. Any
   additional information about a date or time zone is ignored when calculating
   the difference.
 
-  The answer can be returned in any `:hour`, `:minute`, `:second` or any
-  subsecond `unit` available from `t:System.time_unit/0`. If the first time
-  value is earlier than the second, a negative number is returned.
+  The answer can be returned in any `unit` available from
+  `t:System.time_unit/0`. If the first unit is smaller than
+  the second, a negative number is returned.
 
-  The unit is measured according to `Calendar.ISO` and defaults to `:second`.
-  Fractional results are not supported and are truncated.
+  This function returns the difference in seconds where seconds
+  are measured according to `Calendar.ISO`.
 
   ## Examples
 
@@ -712,49 +594,10 @@ defmodule Time do
       iex> Time.diff(~T[00:29:10], ~T[00:29:12], :microsecond)
       -2_000_000
 
-      iex> Time.diff(~T[02:29:10], ~T[00:29:10], :hour)
-      2
-      iex> Time.diff(~T[02:29:10], ~T[00:29:11], :hour)
-      1
-
   """
   @doc since: "1.5.0"
-  @spec diff(Calendar.time(), Calendar.time(), :hour | :minute | System.time_unit()) :: integer
-  def diff(time1, time2, unit \\ :second)
-
-  def diff(time1, time2, :hour) do
-    diff(time1, time2, :second) |> div(3600)
-  end
-
-  def diff(time1, time2, :minute) do
-    diff(time1, time2, :second) |> div(60)
-  end
-
-  def diff(
-        %{
-          calendar: Calendar.ISO,
-          hour: hour1,
-          minute: minute1,
-          second: second1,
-          microsecond: {microsecond1, @parts_per_day}
-        },
-        %{
-          calendar: Calendar.ISO,
-          hour: hour2,
-          minute: minute2,
-          second: second2,
-          microsecond: {microsecond2, @parts_per_day}
-        },
-        unit
-      ) do
-    total =
-      (hour1 - hour2) * 3_600_000_000 + (minute1 - minute2) * 60_000_000 +
-        (second1 - second2) * 1_000_000 + (microsecond1 - microsecond2)
-
-    System.convert_time_unit(total, :microsecond, unit)
-  end
-
-  def diff(time1, time2, unit) do
+  @spec diff(Calendar.time(), Calendar.time(), System.time_unit()) :: integer
+  def diff(time1, time2, unit \\ :second) do
     fraction1 = to_day_fraction(time1)
     fraction2 = to_day_fraction(time2)
 
@@ -766,9 +609,6 @@ defmodule Time do
   Returns the given time with the microsecond field truncated to the given
   precision (`:microsecond`, `millisecond` or `:second`).
 
-  The given time is returned unchanged if it already has lower precision than
-  the given precision.
-
   ## Examples
 
       iex> Time.truncate(~T[01:01:01.123456], :microsecond)
@@ -814,20 +654,20 @@ defmodule Time do
   end
 
   defimpl Inspect do
-    def inspect(time, _) do
+    def inspect(%{calendar: Calendar.ISO} = time, _) do
       %{
         hour: hour,
         minute: minute,
         second: second,
         microsecond: microsecond,
-        calendar: calendar
+        calendar: Calendar.ISO
       } = time
 
-      "~T[" <>
-        calendar.time_to_string(hour, minute, second, microsecond) <> suffix(calendar) <> "]"
+      "~T[" <> Calendar.ISO.time_to_string(hour, minute, second, microsecond) <> "]"
     end
 
-    defp suffix(Calendar.ISO), do: ""
-    defp suffix(calendar), do: " " <> inspect(calendar)
+    def inspect(time, opts) do
+      Inspect.Any.inspect(time, opts)
+    end
   end
 end

lib/elixir/lib/calendar/time_zone_database.ex

@@ -1,96 +0,0 @@
-defmodule Calendar.TimeZoneDatabase do
-  @moduledoc """
-  This module defines a behaviour for providing time zone data.
-
-  IANA provides time zone data that includes data about different
-  UTC offsets and standard offsets for time zones.
-  """
-
-  @typedoc """
-  A period where a certain combination of UTC offset, standard offset and zone
-  abbreviation is in effect.
-
-  For instance one period could be the summer of 2018 in "Europe/London" where summer time /
-  daylight saving time is in effect and lasts from spring to autumn. At autumn the `std_offset`
-  changes along with the `zone_abbr` so a different period is needed during winter.
-  """
-  @type time_zone_period :: %{
-          optional(any) => any,
-          utc_offset: Calendar.utc_offset(),
-          std_offset: Calendar.std_offset(),
-          zone_abbr: Calendar.zone_abbr()
-        }
-
-  @typedoc """
-  Limit for when a certain time zone period begins or ends.
-
-  A beginning is inclusive. An ending is exclusive. Eg. if a period is from
-  2015-03-29 01:00:00 and until 2015-10-25 01:00:00, the period includes and
-  begins from the beginning of 2015-03-29 01:00:00 and lasts until just before
-  2015-10-25 01:00:00.
-
-  A beginning or end for certain periods are infinite. For instance the latest
-  period for time zones without DST or plans to change. However for the purpose
-  of this behaviour they are only used for gaps in wall time where the needed
-  period limits are at a certain time.
-  """
-  @type time_zone_period_limit :: Calendar.naive_datetime()
-
-  @doc """
-  Time zone period for a point in time in UTC for a specific time zone.
-
-  Takes a time zone name and a point in time for UTC and returns a
-  `time_zone_period` for that point in time.
-  """
-  @doc since: "1.8.0"
-  @callback time_zone_period_from_utc_iso_days(Calendar.iso_days(), Calendar.time_zone()) ::
-              {:ok, time_zone_period}
-              | {:error, :time_zone_not_found | :utc_only_time_zone_database}
-
-  @doc """
-  Possible time zone periods for a certain time zone and wall clock date and time.
-
-  When the provided `datetime` is ambiguous a tuple with `:ambiguous` and two possible
-  periods. The periods in the list are sorted with the first element being the one that begins first.
-
-  When the provided `datetime` is in a gap - for instance during the "spring forward" when going
-  from winter time to summer time, a tuple with `:gap` and two periods with limits are returned
-  in a nested tuple. The first nested two-tuple is the period before the gap and a naive datetime
-  with a limit for when the period ends (wall time). The second nested two-tuple is the period
-  just after the gap and a datetime (wall time) for when the period begins just after the gap.
-
-  If there is only a single possible period for the provided `datetime`, then a tuple with `:ok`
-  and the `time_zone_period` is returned.
-  """
-  @doc since: "1.8.0"
-  @callback time_zone_periods_from_wall_datetime(Calendar.naive_datetime(), Calendar.time_zone()) ::
-              {:ok, time_zone_period}
-              | {:ambiguous, time_zone_period, time_zone_period}
-              | {:gap, {time_zone_period, time_zone_period_limit},
-                 {time_zone_period, time_zone_period_limit}}
-              | {:error, :time_zone_not_found | :utc_only_time_zone_database}
-end
-
-defmodule Calendar.UTCOnlyTimeZoneDatabase do
-  @moduledoc """
-  Built-in time zone database that works only in Etc/UTC.
-
-  For all other time zones, it returns `{:error, :utc_only_time_zone_database}`.
-  """
-
-  @behaviour Calendar.TimeZoneDatabase
-
-  @impl true
-  def time_zone_period_from_utc_iso_days(_, "Etc/UTC"),
-    do: {:ok, %{std_offset: 0, utc_offset: 0, zone_abbr: "UTC"}}
-
-  def time_zone_period_from_utc_iso_days(_, _),
-    do: {:error, :utc_only_time_zone_database}
-
-  @impl true
-  def time_zone_periods_from_wall_datetime(_, "Etc/UTC"),
-    do: {:ok, %{std_offset: 0, utc_offset: 0, zone_abbr: "UTC"}}
-
-  def time_zone_periods_from_wall_datetime(_, _),
-    do: {:error, :utc_only_time_zone_database}
-end

lib/elixir/lib/code/identifier.ex

@@ -14,7 +14,7 @@ defmodule Code.Identifier do
   def unary_op(op) do
     cond do
       op in [:&] -> {:non_associative, 90}
-      op in [:!, :^, :not, :+, :-, :"~~~"] -> {:non_associative, 300}
+      op in [:!, :^, :not, :+, :-, :~~~] -> {:non_associative, 300}
       op in [:@] -> {:non_associative, 320}
       true -> :error
     end
@@ -34,26 +34,159 @@ defmodule Code.Identifier do
     cond do
       op in [:<-, :\\] -> {:left, 40}
       op in [:when] -> {:right, 50}
-      op in [:"::"] -> {:right, 60}
+      op in [:::] -> {:right, 60}
       op in [:|] -> {:right, 70}
       op in [:=] -> {:right, 100}
-      op in [:||, :|||, :or] -> {:left, 120}
-      op in [:&&, :&&&, :and] -> {:left, 130}
-      op in [:==, :!=, :=~, :===, :!==] -> {:left, 140}
-      op in [:<, :<=, :>=, :>] -> {:left, 150}
-      op in [:|>, :<<<, :>>>, :<~, :~>, :<<~, :~>>, :<~>, :"<|>"] -> {:left, 160}
-      op in [:in] -> {:left, 170}
-      op in [:"^^^"] -> {:left, 180}
-      op in [:"//"] -> {:right, 190}
-      op in [:++, :--, :.., :<>, :+++, :---] -> {:right, 200}
+      op in [:||, :|||, :or] -> {:left, 130}
+      op in [:&&, :&&&, :and] -> {:left, 140}
+      op in [:==, :!=, :=~, :===, :!==] -> {:left, 150}
+      op in [:<, :<=, :>=, :>] -> {:left, 160}
+      op in [:|>, :<<<, :>>>, :<~, :~>, :<<~, :~>>, :<~>, :<|>] -> {:left, 170}
+      op in [:in] -> {:left, 180}
+      op in [:^^^] -> {:left, 190}
+      op in [:++, :--, :.., :<>] -> {:right, 200}
       op in [:+, :-] -> {:left, 210}
       op in [:*, :/] -> {:left, 220}
-      op in [:**] -> {:left, 230}
       op in [:.] -> {:left, 310}
       true -> :error
     end
   end
 
+  @doc """
+  Classifies the given atom into one of the following categories:
+
+    * `:alias` - a valid Elixir alias, like `Foo`, `Foo.Bar` and so on
+
+    * `:callable_local` - an atom that can be used as a local call;
+      this category includes identifiers like `:foo`
+
+    * `:callable_operators` - all callable operators, such as `:<>`. Note
+      operators such as `:..` are not callable because of ambiguity
+
+    * `:not_callable` - an atom that cannot be used as a function call after the
+      `.` operator (for example, `:<<>>` is not callable because `Foo.<<>>` is a
+      syntax error); this category includes atoms like `:Foo`, since they are
+      valid identifiers but they need quotes to be used in function calls
+      (`Foo."Bar"`)
+
+    * `:other` - any other atom (these are usually escaped when inspected, like
+      `:"foo and bar"`)
+
+  """
+  def classify(atom) when is_atom(atom) do
+    charlist = Atom.to_charlist(atom)
+
+    cond do
+      atom in [:%, :%{}, :{}, :<<>>, :..., :.., :., :->] ->
+        :not_callable
+
+      unary_op(atom) != :error or binary_op(atom) != :error ->
+        :callable_operator
+
+      valid_alias?(charlist) ->
+        :alias
+
+      true ->
+        case :elixir_config.safe_get(:identifier_tokenizer, String.Tokenizer).tokenize(charlist) do
+          {kind, _acc, [], _, _, special} ->
+            if kind == :identifier and not :lists.member(?@, special) do
+              :callable_local
+            else
+              :not_callable
+            end
+
+          _ ->
+            :other
+        end
+    end
+  end
+
+  defp valid_alias?('Elixir' ++ rest), do: valid_alias_piece?(rest)
+  defp valid_alias?(_other), do: false
+
+  defp valid_alias_piece?([?., char | rest]) when char >= ?A and char <= ?Z,
+    do: valid_alias_piece?(trim_leading_while_valid_identifier(rest))
+
+  defp valid_alias_piece?([]), do: true
+  defp valid_alias_piece?(_other), do: false
+
+  defp trim_leading_while_valid_identifier([char | rest])
+       when char >= ?a and char <= ?z
+       when char >= ?A and char <= ?Z
+       when char >= ?0 and char <= ?9
+       when char == ?_ do
+    trim_leading_while_valid_identifier(rest)
+  end
+
+  defp trim_leading_while_valid_identifier(other) do
+    other
+  end
+
+  @doc """
+  Inspects the identifier as an atom.
+  """
+  def inspect_as_atom(atom) when is_nil(atom) or is_boolean(atom) do
+    Atom.to_string(atom)
+  end
+
+  def inspect_as_atom(atom) when is_atom(atom) do
+    binary = Atom.to_string(atom)
+
+    case classify(atom) do
+      :alias ->
+        case binary do
+          binary when binary in ["Elixir", "Elixir.Elixir"] -> binary
+          "Elixir.Elixir." <> _rest -> binary
+          "Elixir." <> rest -> rest
+        end
+
+      type when type in [:callable_local, :callable_operator, :not_callable] ->
+        ":" <> binary
+
+      :other ->
+        {escaped, _} = escape(binary, ?")
+        IO.iodata_to_binary([?:, ?", escaped, ?"])
+    end
+  end
+
+  @doc """
+  Inspects the given identifier as a key.
+  """
+  def inspect_as_key(atom) when is_atom(atom) do
+    binary = Atom.to_string(atom)
+
+    case classify(atom) do
+      type when type in [:callable_local, :callable_operator, :not_callable] ->
+        IO.iodata_to_binary([binary, ?:])
+
+      _ ->
+        {escaped, _} = escape(binary, ?")
+        IO.iodata_to_binary([?", escaped, ?", ?:])
+    end
+  end
+
+  @doc """
+  Inspects the given identifier as a function name.
+  """
+  def inspect_as_function(atom) when is_atom(atom) do
+    binary = Atom.to_string(atom)
+
+    case classify(atom) do
+      type when type in [:callable_local, :callable_operator] ->
+        binary
+
+      type ->
+        escaped =
+          if type in [:not_callable, :alias] do
+            binary
+          else
+            elem(escape(binary, ?"), 0)
+          end
+
+        IO.iodata_to_binary([?", escaped, ?"])
+    end
+  end
+
   @doc """
   Extracts the name and arity of the parent from the anonymous function identifier.
   """
@@ -71,12 +204,8 @@ defmodule Code.Identifier do
   @doc """
   Escapes the given identifier.
   """
-  @spec escape(binary(), char() | nil, :infinity | non_neg_integer, (char() -> iolist() | false)) ::
-          {escaped :: iolist(), remaining :: binary()}
-  def escape(binary, char, limit \\ :infinity, fun \\ &escape_map/1)
-      when ((char in 0..0x10FFFF or is_nil(char)) and limit == :infinity) or
-             (is_integer(limit) and limit >= 0) do
-    escape(binary, char, limit, [], fun)
+  def escape(other, char, count \\ :infinity, fun \\ &escape_map/1) do
+    escape(other, char, count, [], fun)
   end
 
   defp escape(<<_, _::binary>> = binary, _char, 0, acc, _fun) do

lib/elixir/lib/code/normalizer.ex

@@ -1,593 +0,0 @@
-defmodule Code.Normalizer do
-  @moduledoc false
-
-  defguard is_literal(x)
-           when is_integer(x) or
-                  is_float(x) or
-                  is_binary(x) or
-                  is_atom(x)
-
-  @doc """
-  Wraps literals in the quoted expression to conform to the AST format expected
-  by the formatter.
-  """
-  def normalize(quoted, opts \\ []) do
-    line = Keyword.get(opts, :line, nil)
-    escape = Keyword.get(opts, :escape, true)
-    locals_without_parens = Keyword.get(opts, :locals_without_parens, [])
-
-    state = %{
-      escape: escape,
-      parent_meta: [line: line],
-      locals_without_parens: locals_without_parens ++ Code.Formatter.locals_without_parens()
-    }
-
-    do_normalize(quoted, state)
-  end
-
-  # Wrapped literals should receive the block meta
-  defp do_normalize({:__block__, meta, [literal]}, state)
-       when not is_tuple(literal) or tuple_size(literal) == 2 do
-    normalize_literal(literal, meta, state)
-  end
-
-  # Only normalize the first argument of an alias if it's not an atom
-  defp do_normalize({:__aliases__, meta, [first | rest]}, state) when not is_atom(first) do
-    meta = patch_meta_line(meta, state.parent_meta)
-    first = do_normalize(first, %{state | parent_meta: meta})
-    {:__aliases__, meta, [first | rest]}
-  end
-
-  defp do_normalize({:__aliases__, _, _} = quoted, _state) do
-    quoted
-  end
-
-  # Skip captured arguments like &1
-  defp do_normalize({:&, meta, [term]}, state) when is_integer(term) do
-    meta = patch_meta_line(meta, state.parent_meta)
-    {:&, meta, [term]}
-  end
-
-  # Ranges
-  defp do_normalize(left..right//step, state) do
-    left = do_normalize(left, state)
-    right = do_normalize(right, state)
-    meta = meta_line(state)
-
-    if step == 1 do
-      {:.., meta, [left, right]}
-    else
-      step = do_normalize(step, state)
-      {:"..//", meta, [left, right, step]}
-    end
-  end
-
-  # Bit containers
-  defp do_normalize({:<<>>, _, args} = quoted, state) when is_list(args) do
-    normalize_bitstring(quoted, state)
-  end
-
-  # Atoms with interpolations
-  defp do_normalize(
-         {{:., dot_meta, [:erlang, :binary_to_atom]}, call_meta,
-          [{:<<>>, _, args} = string, :utf8]},
-         state
-       )
-       when is_list(args) do
-    dot_meta = patch_meta_line(dot_meta, state.parent_meta)
-    call_meta = patch_meta_line(call_meta, dot_meta)
-
-    utf8 =
-      if args == [] or interpolated?(string) do
-        # a non-normalized :utf8 atom signals an atom interpolation
-        :utf8
-      else
-        normalize_literal(:utf8, [], state)
-      end
-
-    string =
-      if state.escape do
-        normalize_bitstring(string, state, true)
-      else
-        normalize_bitstring(string, state)
-      end
-
-    {{:., dot_meta, [:erlang, :binary_to_atom]}, call_meta, [string, utf8]}
-  end
-
-  # Charlists with interpolations
-  defp do_normalize({{:., dot_meta, [List, :to_charlist]}, call_meta, [parts]}, state) do
-    parts =
-      Enum.map(parts, fn
-        {{:., part_dot_meta, [Kernel, :to_string]}, part_call_meta, args} ->
-          args = normalize_args(args, state)
-
-          {{:., part_dot_meta, [Kernel, :to_string]}, part_call_meta, args}
-
-        part ->
-          if state.escape do
-            maybe_escape_literal(part, state)
-          else
-            part
-          end
-      end)
-
-    {{:., dot_meta, [List, :to_charlist]}, call_meta, [parts]}
-  end
-
-  # Don't normalize the `Access` atom in access syntax
-  defp do_normalize({:., meta, [Access, :get]}, state) do
-    meta = patch_meta_line(meta, state.parent_meta)
-    {:., meta, [Access, :get]}
-  end
-
-  # Only normalize the left side of the dot operator
-  # The right hand side is an atom in the AST but it's not an atom literal, so
-  # it should not be wrapped
-  defp do_normalize({:., meta, [left, right]}, state) do
-    meta = patch_meta_line(meta, state.parent_meta)
-
-    left = do_normalize(left, %{state | parent_meta: meta})
-
-    {:., meta, [left, right]}
-  end
-
-  # A list of left to right arrows is not considered as a list literal, so it's not wrapped
-  defp do_normalize([{:->, _, [_ | _]} | _] = quoted, state) do
-    normalize_args(quoted, state)
-  end
-
-  # left -> right
-  defp do_normalize({:->, meta, [left, right]}, state) do
-    meta = patch_meta_line(meta, state.parent_meta)
-
-    left = normalize_args(left, %{state | parent_meta: meta})
-    right = do_normalize(right, %{state | parent_meta: meta})
-    {:->, meta, [left, right]}
-  end
-
-  # Maps
-  defp do_normalize({:%{}, meta, args}, state) when is_list(args) do
-    meta =
-      if meta == [] do
-        line = state.parent_meta[:line]
-        [line: line, closing: [line: line]]
-      else
-        meta
-      end
-
-    state = %{state | parent_meta: meta}
-
-    args =
-      case args do
-        [{:|, pipe_meta, [left, right]}] ->
-          left = do_normalize(left, state)
-          right = normalize_map_args(right, state)
-          [{:|, pipe_meta, [left, right]}]
-
-        [{_, _, _} = call] ->
-          [do_normalize(call, state)]
-
-        args ->
-          normalize_map_args(args, state)
-      end
-
-    {:%{}, meta, args}
-  end
-
-  # Sigils
-  defp do_normalize({sigil, meta, [{:<<>>, _, args} = string, modifiers]} = quoted, state)
-       when is_list(args) and is_atom(sigil) do
-    case Atom.to_string(sigil) do
-      <<"sigil_", _name>> ->
-        meta =
-          meta
-          |> patch_meta_line(state.parent_meta)
-          |> Keyword.put_new(:delimiter, "\"")
-
-        {sigil, meta, [do_normalize(string, %{state | parent_meta: meta}), modifiers]}
-
-      _ ->
-        normalize_call(quoted, state)
-    end
-  end
-
-  # Tuples
-  defp do_normalize({:{}, meta, args} = quoted, state) when is_list(args) do
-    {last_arg, args} = List.pop_at(args, -1)
-
-    if args != [] and match?([_ | _], last_arg) and keyword?(last_arg) do
-      args = normalize_args(args, state)
-      kw_list = normalize_kw_args(last_arg, state, true)
-      {:{}, meta, args ++ kw_list}
-    else
-      normalize_call(quoted, state)
-    end
-  end
-
-  # Module attributes
-  defp do_normalize({:@, meta, [{name, name_meta, [value]}]}, state) do
-    value =
-      cond do
-        keyword?(value) and value != [] ->
-          normalize_kw_args(value, state, true)
-
-        is_list(value) ->
-          normalize_literal(value, meta, state)
-
-        true ->
-          do_normalize(value, state)
-      end
-
-    {:@, meta, [{name, name_meta, [value]}]}
-  end
-
-  # Regular blocks
-  defp do_normalize({:__block__, meta, args}, state) when is_list(args) do
-    {:__block__, meta, normalize_args(args, state)}
-  end
-
-  # Calls
-  defp do_normalize({_, _, args} = quoted, state) when is_list(args) do
-    normalize_call(quoted, state)
-  end
-
-  # Vars
-  defp do_normalize({_, _, context} = quoted, _state) when is_atom(context) do
-    quoted
-  end
-
-  # Literals
-  defp do_normalize(quoted, state) do
-    normalize_literal(quoted, [], state)
-  end
-
-  # Numbers
-  defp normalize_literal(number, meta, state) when is_number(number) do
-    meta =
-      meta
-      |> Keyword.put_new(:token, inspect(number))
-      |> patch_meta_line(state.parent_meta)
-
-    {:__block__, meta, [number]}
-  end
-
-  # Atom, Strings
-  defp normalize_literal(literal, meta, state) when is_atom(literal) or is_binary(literal) do
-    meta = patch_meta_line(meta, state.parent_meta)
-    literal = maybe_escape_literal(literal, state)
-
-    if is_atom(literal) and Macro.classify_atom(literal) == :alias and
-         is_nil(meta[:delimiter]) do
-      segments =
-        case Atom.to_string(literal) do
-          "Elixir" ->
-            [:"Elixir"]
-
-          "Elixir." <> segments ->
-            segments
-            |> String.split(".")
-            |> Enum.map(&String.to_atom/1)
-        end
-
-      {:__aliases__, meta, segments}
-    else
-      {:__block__, meta, [literal]}
-    end
-  end
-
-  # 2-tuples
-  defp normalize_literal({left, right}, meta, state) do
-    meta = patch_meta_line(meta, state.parent_meta)
-    state = %{state | parent_meta: meta}
-
-    if match?([_ | _], right) and keyword?(right) do
-      {:__block__, meta, [{do_normalize(left, state), normalize_kw_args(right, state, true)}]}
-    else
-      {:__block__, meta, [{do_normalize(left, state), do_normalize(right, state)}]}
-    end
-  end
-
-  # Lists
-  defp normalize_literal(list, meta, state) when is_list(list) do
-    if list != [] and List.ascii_printable?(list) do
-      # It's a charlist
-      list =
-        if state.escape do
-          {string, _} = Code.Identifier.escape(IO.chardata_to_string(list), nil)
-          IO.iodata_to_binary(string) |> to_charlist()
-        else
-          list
-        end
-
-      meta =
-        meta
-        |> Keyword.put_new(:delimiter, "'")
-        |> patch_meta_line(state.parent_meta)
-
-      {:__block__, meta, [list]}
-    else
-      meta =
-        if line = state.parent_meta[:line] do
-          meta
-          |> Keyword.put_new(:closing, line: line)
-          |> patch_meta_line(state.parent_meta)
-        else
-          meta
-        end
-
-      {:__block__, meta, [normalize_kw_args(list, state, false)]}
-    end
-  end
-
-  # Probably an invalid value, wrap it and send it upstream
-  defp normalize_literal(quoted, meta, _state) do
-    {:__block__, meta, [quoted]}
-  end
-
-  defp normalize_call({form, meta, args}, state) do
-    meta = patch_meta_line(meta, state.parent_meta)
-    arity = length(args)
-
-    # Only normalize the form if it's a qualified call
-    form =
-      if is_atom(form) do
-        form
-      else
-        do_normalize(form, %{state | parent_meta: meta})
-      end
-
-    meta =
-      if is_nil(meta[:no_parens]) and is_nil(meta[:closing]) and is_nil(meta[:do]) and
-           not Code.Formatter.local_without_parens?(form, arity, state.locals_without_parens) do
-        [closing: [line: meta[:line]]] ++ meta
-      else
-        meta
-      end
-
-    cond do
-      Keyword.has_key?(meta, :do) or match?([{{:__block__, _, [:do]}, _} | _], List.last(args)) ->
-        # def foo do :ok end
-        # def foo, do: :ok
-        normalize_kw_blocks(form, meta, args, state)
-
-      match?([{:do, _} | _], List.last(args)) ->
-        # Non normalized kw blocks
-        line = state.parent_meta[:line]
-        meta = meta ++ [do: [line: line], end: [line: line]]
-        normalize_kw_blocks(form, meta, args, state)
-
-      allow_keyword?(form, arity) ->
-        args = normalize_args(args, %{state | parent_meta: state.parent_meta})
-        {last_arg, leading_args} = List.pop_at(args, -1, [])
-
-        last_args =
-          case last_arg do
-            {:__block__, _, [[{{:__block__, key_meta, _}, _} | _]] = last_args} ->
-              if key_meta[:format] == :keyword do
-                last_args
-              else
-                [last_arg]
-              end
-
-            [] ->
-              []
-
-            _ ->
-              [last_arg]
-          end
-
-        {form, meta, leading_args ++ last_args}
-
-      true ->
-        args = normalize_args(args, %{state | parent_meta: state.parent_meta})
-        {form, meta, args}
-    end
-  end
-
-  defp allow_keyword?(:when, 2), do: true
-  defp allow_keyword?(:{}, _), do: false
-  defp allow_keyword?(op, arity), do: not is_atom(op) or not Macro.operator?(op, arity)
-
-  defp normalize_bitstring({:<<>>, meta, parts} = quoted, state, escape_interpolation \\ false) do
-    meta = patch_meta_line(meta, state.parent_meta)
-
-    parts =
-      if interpolated?(quoted) do
-        normalize_interpolation_parts(parts, %{state | parent_meta: meta}, escape_interpolation)
-      else
-        state = %{state | parent_meta: meta}
-
-        Enum.map(parts, fn part ->
-          with {:"::", meta, [left, _]} <- part,
-               true <- meta[:inferred_bitstring_spec] do
-            do_normalize(left, state)
-          else
-            _ -> do_normalize(part, state)
-          end
-        end)
-      end
-
-    {:<<>>, meta, parts}
-  end
-
-  defp normalize_interpolation_parts(parts, state, escape_interpolation) do
-    Enum.map(parts, fn
-      {:"::", interpolation_meta,
-       [
-         {{:., dot_meta, [Kernel, :to_string]}, middle_meta, [middle]},
-         {:binary, binary_meta, context}
-       ]} ->
-        middle = do_normalize(middle, %{state | parent_meta: dot_meta})
-
-        {:"::", interpolation_meta,
-         [
-           {{:., dot_meta, [Kernel, :to_string]}, middle_meta, [middle]},
-           {:binary, binary_meta, context}
-         ]}
-
-      part ->
-        if escape_interpolation do
-          maybe_escape_literal(part, state)
-        else
-          part
-        end
-    end)
-  end
-
-  defp normalize_map_args(args, state) do
-    Enum.map(normalize_kw_args(args, state, false), fn
-      {:__block__, _, [{_, _} = pair]} -> pair
-      pair -> pair
-    end)
-  end
-
-  defp normalize_kw_blocks(form, meta, args, state) do
-    {kw_blocks, leading_args} = List.pop_at(args, -1)
-
-    kw_blocks =
-      Enum.map(kw_blocks, fn {tag, block} ->
-        block = do_normalize(block, %{state | parent_meta: meta})
-
-        block =
-          case block do
-            {_, _, [[{:->, _, _} | _] = block]} -> block
-            block -> block
-          end
-
-        # Only wrap the tag if it isn't already wrapped
-        tag =
-          case tag do
-            {:__block__, _, _} -> tag
-            _ -> {:__block__, [line: meta[:line]], [tag]}
-          end
-
-        {tag, block}
-      end)
-
-    leading_args = normalize_args(leading_args, %{state | parent_meta: meta})
-    {form, meta, leading_args ++ [kw_blocks]}
-  end
-
-  defp normalize_kw_args(elems, state, keyword?)
-
-  defp normalize_kw_args(
-         [{{:__block__, key_meta, [key]}, value} = first | rest] = current,
-         state,
-         keyword?
-       )
-       when is_atom(key) do
-    keyword? = keyword? or keyword?(current)
-
-    first =
-      if key_meta[:format] == :keyword and not keyword? do
-        key_meta = Keyword.delete(key_meta, :format)
-        line = key_meta[:line] || meta_line(state)
-        {:__block__, [line: line], [{{:__block__, key_meta, [key]}, value}]}
-      else
-        first
-      end
-
-    [first | normalize_kw_args(rest, state, keyword?)]
-  end
-
-  defp normalize_kw_args([{left, right} | rest] = current, state, keyword?) do
-    keyword? = keyword? or keyword?(current)
-
-    left =
-      if keyword? do
-        meta = [format: :keyword] ++ meta_line(state)
-        {:__block__, meta, [maybe_escape_literal(left, state)]}
-      else
-        do_normalize(left, state)
-      end
-
-    right = do_normalize(right, state)
-
-    pair =
-      with {:__block__, meta, _} <- left,
-           :keyword <- meta[:format] do
-        {left, right}
-      else
-        _ -> {:__block__, meta_line(state), [{left, right}]}
-      end
-
-    [pair | normalize_kw_args(rest, state, keyword?)]
-  end
-
-  defp normalize_kw_args([first | rest], state, keyword?) do
-    [do_normalize(first, state) | normalize_kw_args(rest, state, keyword?)]
-  end
-
-  defp normalize_kw_args([], _state, _keyword?) do
-    []
-  end
-
-  defp normalize_args(args, state) do
-    Enum.map(args, &do_normalize(&1, state))
-  end
-
-  defp maybe_escape_literal(string, %{escape: true}) when is_binary(string) do
-    {string, _} = Code.Identifier.escape(string, nil)
-    IO.iodata_to_binary(string)
-  end
-
-  defp maybe_escape_literal(atom, %{escape: true} = state) when is_atom(atom) do
-    atom
-    |> Atom.to_string()
-    |> maybe_escape_literal(state)
-    |> String.to_atom()
-  end
-
-  defp maybe_escape_literal(term, _) do
-    term
-  end
-
-  # Check if we have an interpolated string.
-  defp interpolated?({:<<>>, _, [_ | _] = parts}) do
-    Enum.all?(parts, fn
-      {:"::", _, [{{:., _, [Kernel, :to_string]}, _, [_]}, {:binary, _, _}]} -> true
-      binary when is_binary(binary) -> true
-      _ -> false
-    end)
-  end
-
-  defp interpolated?(_) do
-    false
-  end
-
-  defp patch_meta_line(meta, parent_meta) do
-    with nil <- meta[:line],
-         line when is_integer(line) <- parent_meta[:line] do
-      [line: line] ++ meta
-    else
-      _ -> meta
-    end
-  end
-
-  defp meta_line(state) do
-    if line = state.parent_meta[:line] do
-      [line: line]
-    else
-      []
-    end
-  end
-
-  defp keyword?([{{:__block__, key_meta, [key]}, _} | rest]) when is_atom(key) do
-    if key_meta[:format] == :keyword do
-      keyword?(rest)
-    else
-      false
-    end
-  end
-
-  defp keyword?([{key, _value} | rest]) when is_atom(key) do
-    case Atom.to_charlist(key) do
-      'Elixir.' ++ _ -> false
-      _ -> keyword?(rest)
-    end
-  end
-
-  defp keyword?([]), do: true
-  defp keyword?(_other), do: false
-end

lib/elixir/lib/code/typespec.ex

@@ -7,9 +7,9 @@ defmodule Code.Typespec do
   @spec spec_to_quoted(atom, tuple) :: {atom, keyword, [Macro.t()]}
   def spec_to_quoted(name, spec)
 
-  def spec_to_quoted(name, {:type, anno, :fun, [{:type, _, :product, args}, result]})
+  def spec_to_quoted(name, {:type, line, :fun, [{:type, _, :product, args}, result]})
       when is_atom(name) do
-    meta = meta(anno)
+    meta = [line: line]
     body = {name, meta, Enum.map(args, &typespec_to_quoted/1)}
 
     vars =
@@ -18,7 +18,7 @@ defmodule Code.Typespec do
           uniq: true,
           do: {var, {:var, meta, nil}}
 
-    spec = {:"::", meta, [body, typespec_to_quoted(result)]}
+    spec = {:::, meta, [body, typespec_to_quoted(result)]}
 
     if vars == [] do
       spec
@@ -27,13 +27,11 @@ defmodule Code.Typespec do
     end
   end
 
-  def spec_to_quoted(name, {:type, anno, :fun, []}) when is_atom(name) do
-    meta = meta(anno)
-    {:"::", meta, [{name, meta, []}, quote(do: term)]}
+  def spec_to_quoted(name, {:type, line, :fun, []}) when is_atom(name) do
+    {:::, [line: line], [{name, [line: line], []}, quote(do: term)]}
   end
 
-  def spec_to_quoted(name, {:type, anno, :bounded_fun, [type, constrs]}) when is_atom(name) do
-    meta = meta(anno)
+  def spec_to_quoted(name, {:type, line, :bounded_fun, [type, constrs]}) when is_atom(name) do
     {:type, _, :fun, [{:type, _, :product, args}, result]} = type
 
     guards =
@@ -41,6 +39,7 @@ defmodule Code.Typespec do
         {erl_to_ex_var(var), typespec_to_quoted(type)}
       end
 
+    meta = [line: line]
     ignore_vars = Keyword.keys(guards)
 
     vars =
@@ -53,7 +52,7 @@ defmodule Code.Typespec do
     args = for arg <- args, do: typespec_to_quoted(arg)
 
     when_args = [
-      {:"::", meta, [{name, meta, args}, typespec_to_quoted(result)]},
+      {:::, meta, [{name, [line: line], args}, typespec_to_quoted(result)]},
       guards ++ vars
     ]
 
@@ -153,32 +152,44 @@ defmodule Code.Typespec do
     end
   end
 
+  # TODO: Do not rely on abstract_code when OTP 20+ support is dropped (v1.8).
+  # We should then be able to simplify this code and use `with`.
   defp typespecs_abstract_code(module) do
-    with {module, binary} <- get_module_and_beam(module),
-         {:ok, {_, [debug_info: {:debug_info_v1, backend, data}]}} <-
-           :beam_lib.chunks(binary, [:debug_info]) do
-      case data do
-        {:elixir_v1, %{}, specs} ->
-          # Fast path to avoid translation to Erlang from Elixir.
-          {:ok, specs}
+    case get_module_and_beam(module) do
+      {module, binary} ->
+        case :beam_lib.chunks(binary, [:debug_info]) do
+          {:ok, {_, [debug_info: {:debug_info_v1, backend, data}]}} ->
+            case data do
+              {:elixir_v1, %{}, specs} ->
+                # Fast path to avoid translation to Erlang from Elixir.
+                {:ok, specs}
 
-        _ ->
-          case backend.debug_info(:erlang_v1, module, data, []) do
-            {:ok, abstract_code} -> {:ok, abstract_code}
-            _ -> :error
-          end
-      end
-    else
-      _ -> :error
+              _ ->
+                case backend.debug_info(:erlang_v1, module, data, []) do
+                  {:ok, abstract_code} -> {:ok, abstract_code}
+                  _ -> :error
+                end
+            end
+
+          _ ->
+            case :beam_lib.chunks(binary, [:abstract_code]) do
+              {:ok, {_, [{:abstract_code, {_raw_abstract_v1, abstract_code}}]}} ->
+                {:ok, abstract_code}
+
+              _ ->
+                :error
+            end
+        end
+
+      :error ->
+        :error
     end
   end
 
   defp get_module_and_beam(module) when is_atom(module) do
-    with {^module, beam, _filename} <- :code.get_object_code(module),
-         {:ok, ^module} <- beam |> :beam_lib.info() |> Keyword.fetch(:module) do
-      {module, beam}
-    else
-      _ -> :error
+    case :code.get_object_code(module) do
+      {^module, beam, _filename} -> {module, beam}
+      :error -> :error
     end
   end
 
@@ -191,27 +202,27 @@ defmodule Code.Typespec do
 
   ## To AST conversion
 
-  defp collect_vars({:ann_type, _anno, args}) when is_list(args) do
+  defp collect_vars({:ann_type, _line, args}) when is_list(args) do
     []
   end
 
-  defp collect_vars({:type, _anno, _kind, args}) when is_list(args) do
+  defp collect_vars({:type, _line, _kind, args}) when is_list(args) do
     Enum.flat_map(args, &collect_vars/1)
   end
 
-  defp collect_vars({:remote_type, _anno, args}) when is_list(args) do
+  defp collect_vars({:remote_type, _line, args}) when is_list(args) do
     Enum.flat_map(args, &collect_vars/1)
   end
 
-  defp collect_vars({:typed_record_field, _anno, type}) do
+  defp collect_vars({:typed_record_field, _line, type}) do
     collect_vars(type)
   end
 
-  defp collect_vars({:paren_type, _anno, [type]}) do
+  defp collect_vars({:paren_type, _line, [type]}) do
     collect_vars(type)
   end
 
-  defp collect_vars({:var, _anno, var}) do
+  defp collect_vars({:var, _line, var}) do
     [erl_to_ex_var(var)]
   end
 
@@ -219,48 +230,47 @@ defmodule Code.Typespec do
     []
   end
 
-  defp typespec_to_quoted({:user_type, anno, name, args}) do
+  defp typespec_to_quoted({:user_type, line, name, args}) do
+    typespec_to_quoted({:type, line, name, args})
+  end
+
+  defp typespec_to_quoted({:type, line, :tuple, :any}) do
+    {:tuple, [line: line], []}
+  end
+
+  defp typespec_to_quoted({:type, line, :tuple, args}) do
     args = for arg <- args, do: typespec_to_quoted(arg)
-    {name, meta(anno), args}
+    {:{}, [line: line], args}
   end
 
-  defp typespec_to_quoted({:type, anno, :tuple, :any}) do
-    {:tuple, meta(anno), []}
-  end
-
-  defp typespec_to_quoted({:type, anno, :tuple, args}) do
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    {:{}, meta(anno), args}
-  end
-
-  defp typespec_to_quoted({:type, _anno, :list, [{:type, _, :union, unions} = arg]}) do
+  defp typespec_to_quoted({:type, _line, :list, [{:type, _, :union, unions} = arg]}) do
     case unpack_typespec_kw(unions, []) do
       {:ok, ast} -> ast
       :error -> [typespec_to_quoted(arg)]
     end
   end
 
-  defp typespec_to_quoted({:type, anno, :list, []}) do
-    {:list, meta(anno), []}
+  defp typespec_to_quoted({:type, line, :list, []}) do
+    {:list, [line: line], []}
   end
 
-  defp typespec_to_quoted({:type, _anno, :list, [arg]}) do
+  defp typespec_to_quoted({:type, _line, :list, [arg]}) do
     [typespec_to_quoted(arg)]
   end
 
-  defp typespec_to_quoted({:type, anno, :nonempty_list, []}) do
-    [{:..., meta(anno), nil}]
+  defp typespec_to_quoted({:type, line, :nonempty_list, []}) do
+    [{:..., [line: line], nil}]
   end
 
-  defp typespec_to_quoted({:type, anno, :nonempty_list, [arg]}) do
-    [typespec_to_quoted(arg), {:..., meta(anno), nil}]
+  defp typespec_to_quoted({:type, line, :nonempty_list, [arg]}) do
+    [typespec_to_quoted(arg), {:..., [line: line], nil}]
   end
 
-  defp typespec_to_quoted({:type, anno, :map, :any}) do
-    {:map, meta(anno), []}
+  defp typespec_to_quoted({:type, line, :map, :any}) do
+    {:map, [line: line], []}
   end
 
-  defp typespec_to_quoted({:type, anno, :map, fields}) do
+  defp typespec_to_quoted({:type, line, :map, fields}) do
     fields =
       Enum.map(fields, fn
         {:type, _, :map_field_assoc, :any} ->
@@ -276,19 +286,18 @@ defmodule Code.Typespec do
           {{:optional, [], [typespec_to_quoted(k)]}, typespec_to_quoted(v)}
       end)
 
-    case List.keytake(fields, :__struct__, 0) do
-      {{:__struct__, struct}, fields_pruned} when is_atom(struct) and struct != nil ->
-        map_pruned = {:%{}, meta(anno), fields_pruned}
-        {:%, meta(anno), [struct, map_pruned]}
+    {struct, fields} = Keyword.pop(fields, :__struct__)
+    map = {:%{}, [line: line], fields}
 
-      _ ->
-        {:%{}, meta(anno), fields}
+    if struct do
+      {:%, [line: line], [struct, map]}
+    else
+      map
     end
   end
 
-  defp typespec_to_quoted({:type, anno, :binary, [arg1, arg2]}) do
+  defp typespec_to_quoted({:type, line, :binary, [arg1, arg2]}) do
     [arg1, arg2] = for arg <- [arg1, arg2], do: typespec_to_quoted(arg)
-    line = meta(anno)[:line]
 
     case {typespec_to_quoted(arg1), typespec_to_quoted(arg2)} do
       {arg1, 0} ->
@@ -302,57 +311,57 @@ defmodule Code.Typespec do
     end
   end
 
-  defp typespec_to_quoted({:type, anno, :union, args}) do
+  defp typespec_to_quoted({:type, line, :union, args}) do
     args = for arg <- args, do: typespec_to_quoted(arg)
-    Enum.reduce(Enum.reverse(args), fn arg, expr -> {:|, meta(anno), [arg, expr]} end)
+    Enum.reduce(Enum.reverse(args), fn arg, expr -> {:|, [line: line], [arg, expr]} end)
   end
 
-  defp typespec_to_quoted({:type, anno, :fun, [{:type, _, :product, args}, result]}) do
+  defp typespec_to_quoted({:type, line, :fun, [{:type, _, :product, args}, result]}) do
     args = for arg <- args, do: typespec_to_quoted(arg)
-    [{:->, meta(anno), [args, typespec_to_quoted(result)]}]
+    [{:->, [line: line], [args, typespec_to_quoted(result)]}]
   end
 
-  defp typespec_to_quoted({:type, anno, :fun, [args, result]}) do
-    [{:->, meta(anno), [[typespec_to_quoted(args)], typespec_to_quoted(result)]}]
+  defp typespec_to_quoted({:type, line, :fun, [args, result]}) do
+    [{:->, [line: line], [[typespec_to_quoted(args)], typespec_to_quoted(result)]}]
   end
 
-  defp typespec_to_quoted({:type, anno, :fun, []}) do
-    typespec_to_quoted({:type, anno, :fun, [{:type, anno, :any}, {:type, anno, :any, []}]})
+  defp typespec_to_quoted({:type, line, :fun, []}) do
+    typespec_to_quoted({:type, line, :fun, [{:type, line, :any}, {:type, line, :any, []}]})
   end
 
-  defp typespec_to_quoted({:type, anno, :range, [left, right]}) do
-    {:.., meta(anno), [typespec_to_quoted(left), typespec_to_quoted(right)]}
+  defp typespec_to_quoted({:type, line, :range, [left, right]}) do
+    {:.., [line: line], [typespec_to_quoted(left), typespec_to_quoted(right)]}
   end
 
-  defp typespec_to_quoted({:type, _anno, nil, []}) do
+  defp typespec_to_quoted({:type, _line, nil, []}) do
     []
   end
 
-  defp typespec_to_quoted({:type, anno, name, args}) do
+  defp typespec_to_quoted({:type, line, name, args}) do
     args = for arg <- args, do: typespec_to_quoted(arg)
-    {name, meta(anno), args}
+    {name, [line: line], args}
   end
 
-  defp typespec_to_quoted({:var, anno, var}) do
-    {erl_to_ex_var(var), meta(anno), nil}
+  defp typespec_to_quoted({:var, line, var}) do
+    {erl_to_ex_var(var), line, nil}
   end
 
-  defp typespec_to_quoted({:op, anno, op, arg}) do
-    {op, meta(anno), [typespec_to_quoted(arg)]}
+  defp typespec_to_quoted({:op, line, op, arg}) do
+    {op, [line: line], [typespec_to_quoted(arg)]}
   end
 
-  defp typespec_to_quoted({:remote_type, anno, [mod, name, args]}) do
-    remote_type(anno, mod, name, args)
+  defp typespec_to_quoted({:remote_type, line, [mod, name, args]}) do
+    remote_type(line, mod, name, args)
   end
 
-  defp typespec_to_quoted({:ann_type, anno, [var, type]}) do
-    {:"::", meta(anno), [typespec_to_quoted(var), typespec_to_quoted(type)]}
+  defp typespec_to_quoted({:ann_type, line, [var, type]}) do
+    {:::, [line: line], [typespec_to_quoted(var), typespec_to_quoted(type)]}
   end
 
   defp typespec_to_quoted(
-         {:typed_record_field, {:record_field, anno1, {:atom, anno2, name}}, type}
+         {:typed_record_field, {:record_field, line, {:atom, line1, name}}, type}
        ) do
-    typespec_to_quoted({:ann_type, anno1, [{:var, anno2, name}, type]})
+    typespec_to_quoted({:ann_type, line, [{:var, line1, name}, type]})
   end
 
   defp typespec_to_quoted({:type, _, :any}) do
@@ -363,7 +372,7 @@ defmodule Code.Typespec do
     typespec_to_quoted(type)
   end
 
-  defp typespec_to_quoted({type, _anno, atom}) when is_atom(type) do
+  defp typespec_to_quoted({type, _line, atom}) when is_atom(type) do
     atom
   end
 
@@ -371,30 +380,30 @@ defmodule Code.Typespec do
 
   ## Helpers
 
-  defp remote_type(anno, {:atom, _, :elixir}, {:atom, _, :charlist}, []) do
-    typespec_to_quoted({:type, anno, :charlist, []})
+  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :charlist}, []) do
+    typespec_to_quoted({:type, line, :charlist, []})
   end
 
-  defp remote_type(anno, {:atom, _, :elixir}, {:atom, _, :nonempty_charlist}, []) do
-    typespec_to_quoted({:type, anno, :nonempty_charlist, []})
+  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :nonempty_charlist}, []) do
+    typespec_to_quoted({:type, line, :nonempty_charlist, []})
   end
 
-  defp remote_type(anno, {:atom, _, :elixir}, {:atom, _, :struct}, []) do
-    typespec_to_quoted({:type, anno, :struct, []})
+  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :struct}, []) do
+    typespec_to_quoted({:type, line, :struct, []})
   end
 
-  defp remote_type(anno, {:atom, _, :elixir}, {:atom, _, :as_boolean}, [arg]) do
-    typespec_to_quoted({:type, anno, :as_boolean, [arg]})
+  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :as_boolean}, [arg]) do
+    typespec_to_quoted({:type, line, :as_boolean, [arg]})
   end
 
-  defp remote_type(anno, {:atom, _, :elixir}, {:atom, _, :keyword}, args) do
-    typespec_to_quoted({:type, anno, :keyword, args})
+  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :keyword}, args) do
+    typespec_to_quoted({:type, line, :keyword, args})
   end
 
-  defp remote_type(anno, mod, name, args) do
+  defp remote_type(line, mod, name, args) do
     args = for arg <- args, do: typespec_to_quoted(arg)
-    dot = {:., meta(anno), [typespec_to_quoted(mod), typespec_to_quoted(name)]}
-    {dot, meta(anno), args}
+    dot = {:., [line: line], [typespec_to_quoted(mod), typespec_to_quoted(name)]}
+    {dot, [line: line], args}
   end
 
   defp erl_to_ex_var(var) do
@@ -418,6 +427,4 @@ defmodule Code.Typespec do
   defp unpack_typespec_kw(_, _acc) do
     :error
   end
-
-  defp meta(anno), do: [line: :erl_anno.line(anno)]
 end

lib/elixir/lib/collectable.ex

@@ -17,54 +17,42 @@ defprotocol Collectable do
 
   This design is intentional. `Enumerable` was designed to support infinite
   collections, resources and other structures with fixed shape. For example,
-  it doesn't make sense to insert values into a `Range`, as it has a
-  fixed shape where only the range limits and step are stored.
+  it doesn't make sense to insert values into a range, as it has a fixed
+  shape where just the range limits are stored.
 
   The `Collectable` module was designed to fill the gap left by the
-  `Enumerable` protocol. `Collectable.into/1` can be seen as the opposite of
-  `Enumerable.reduce/3`. If the functions in `Enumerable` are about taking values out,
-  then `Collectable.into/1` is about collecting those values into a structure.
+  `Enumerable` protocol. `into/1` can be seen as the opposite of
+  `Enumerable.reduce/3`. If `Enumerable` is about taking values out,
+  `Collectable.into/1` is about collecting those values into a structure.
 
   ## Examples
 
-  To show how to manually use the `Collectable` protocol, let's play with a
-  simplified implementation for `MapSet`.
+  To show how to manually use the `Collectable` protocol, let's play with its
+  implementation for `MapSet`.
 
       iex> {initial_acc, collector_fun} = Collectable.into(MapSet.new())
       iex> updated_acc = Enum.reduce([1, 2, 3], initial_acc, fn elem, acc ->
       ...>   collector_fun.(acc, {:cont, elem})
       ...> end)
       iex> collector_fun.(updated_acc, :done)
-      MapSet.new([1, 2, 3])
+      #MapSet<[1, 2, 3]>
 
-  To show how the protocol can be implemented, we can again look at the
-  simplified implementation for `MapSet`. In this implementation "collecting" elements
+  To show how the protocol can be implemented, we can take again a look at the
+  implementation for `MapSet`. In this implementation "collecting" elements
   simply means inserting them in the set through `MapSet.put/2`.
 
-      defimpl Collectable, for: MapSet do
-        def into(map_set) do
+      defimpl Collectable do
+        def into(original) do
           collector_fun = fn
-            map_set_acc, {:cont, elem} ->
-              MapSet.put(map_set_acc, elem)
-
-            map_set_acc, :done ->
-              map_set_acc
-
-            _map_set_acc, :halt ->
-              :ok
+            set, {:cont, elem} -> MapSet.put(set, elem)
+            set, :done -> set
+            _set, :halt -> :ok
           end
 
-          initial_acc = map_set
-
-          {initial_acc, collector_fun}
+          {original, collector_fun}
         end
       end
 
-  So now we can call `Enum.into/2`:
-
-      iex> Enum.into([1, 2, 3], MapSet.new())
-      MapSet.new([1, 2, 3])
-
   """
 
   @type command :: {:cont, term} | :done | :halt
@@ -72,11 +60,8 @@ defprotocol Collectable do
   @doc """
   Returns an initial accumulator and a "collector" function.
 
-  Receives a `collectable` which can be used as the initial accumulator that will
-  be passed to the function.
-
-  The collector function receives a term and a command and injects the term into
-  the collectable accumulator on every `{:cont, term}` command.
+  The returned function receives a term and a command and injects the term into
+  the collectable on every `{:cont, term}` command.
 
   `:done` is passed as a command when no further values will be injected. This
   is useful when there's a need to close resources or normalizing values. A
@@ -88,32 +73,16 @@ defprotocol Collectable do
   For examples on how to use the `Collectable` protocol and `into/1` see the
   module documentation.
   """
-  @spec into(t) :: {initial_acc :: term, collector :: (term, command -> t | term)}
+  @spec into(t) :: {term, (term, command -> t | term)}
   def into(collectable)
 end
 
 defimpl Collectable, for: List do
-  def into(list) do
-    # TODO: Change the behaviour so the into always comes last on Elixir v2.0
-    if list != [] do
-      IO.warn(
-        "the Collectable protocol is deprecated for non-empty lists. The behaviour of " <>
-          "Enum.into/2 and \"for\" comprehensions with an :into option is incorrect " <>
-          "when collecting into non-empty lists. If you're collecting into a non-empty keyword " <>
-          "list, consider using Keyword.merge/2 instead. If you're collecting into a non-empty " <>
-          "list, consider concatenating the two lists with the ++ operator."
-      )
-    end
-
+  def into(original) do
     fun = fn
-      list_acc, {:cont, elem} ->
-        [elem | list_acc]
-
-      list_acc, :done ->
-        list ++ :lists.reverse(list_acc)
-
-      _list_acc, :halt ->
-        :ok
+      list, {:cont, x} -> [x | list]
+      list, :done -> original ++ :lists.reverse(list)
+      _, :halt -> :ok
     end
 
     {[], fun}
@@ -121,7 +90,7 @@ defimpl Collectable, for: List do
 end
 
 defimpl Collectable, for: BitString do
-  def into(binary) when is_binary(binary) do
+  def into(original) when is_binary(original) do
     fun = fn
       acc, {:cont, x} when is_binary(x) and is_list(acc) ->
         [acc | x]
@@ -138,14 +107,14 @@ defimpl Collectable, for: BitString do
       acc, :done ->
         IO.iodata_to_binary(acc)
 
-      __acc, :halt ->
+      _, :halt ->
         :ok
     end
 
-    {[binary], fun}
+    {[original], fun}
   end
 
-  def into(bitstring) do
+  def into(original) when is_bitstring(original) do
     fun = fn
       acc, {:cont, x} when is_bitstring(x) ->
         <<acc::bitstring, x::bitstring>>
@@ -153,27 +122,22 @@ defimpl Collectable, for: BitString do
       acc, :done ->
         acc
 
-      _acc, :halt ->
+      _, :halt ->
         :ok
     end
 
-    {bitstring, fun}
+    {original, fun}
   end
 end
 
 defimpl Collectable, for: Map do
-  def into(map) do
+  def into(original) do
     fun = fn
-      map_acc, {:cont, {key, value}} ->
-        Map.put(map_acc, key, value)
-
-      map_acc, :done ->
-        map_acc
-
-      _map_acc, :halt ->
-        :ok
+      map, {:cont, {k, v}} -> :maps.put(k, v, map)
+      map, :done -> map
+      _, :halt -> :ok
     end
 
-    {map, fun}
+    {original, fun}
   end
 end

lib/elixir/lib/config.ex

@@ -1,359 +0,0 @@
-defmodule Config do
-  @moduledoc ~S"""
-  A simple keyword-based configuration API.
-
-  ## Example
-
-  This module is most commonly used to define application configuration,
-  typically in `config/config.exs`:
-
-      import Config
-
-      config :some_app,
-        key1: "value1",
-        key2: "value2"
-
-      import_config "#{config_env()}.exs"
-
-  `import Config` will import the functions `config/2`, `config/3`
-  `config_env/0`, `config_target/0`, and `import_config/1`
-  to help you manage your configuration.
-
-  `config/2` and `config/3` are used to define key-value configuration
-  for a given application. Once Mix starts, it will automatically
-  evaluate the configuration file and persist the configuration above
-  into `:some_app`'s application environment, which can be accessed in
-  as follows:
-
-      "value1" = Application.fetch_env!(:some_app, :key1)
-
-  Finally, the line `import_config "#{config_env()}.exs"` will import
-  other config files based on the current configuration environment,
-  such as `config/dev.exs` and `config/test.exs`.
-
-  `Config` also provides a low-level API for evaluating and reading
-  configuration, under the `Config.Reader` module.
-
-  > **Important:** if you are writing a library to be used by other developers,
-  > it is generally recommended to avoid the application environment, as the
-  > application environment is effectively a global storage. Also note that
-  > the `config/config.exs` of a library is not evaluated when the library is
-  > used as a dependency, as configuration is always meant to configure the
-  > current project. For more information, read our [library guidelines](library-guidelines.md).
-
-  ## Migrating from `use Mix.Config`
-
-  The `Config` module in Elixir was introduced in v1.9 as a replacement to
-  `Mix.Config`, which was specific to Mix and has been deprecated.
-
-  You can leverage `Config` instead of `Mix.Config` in three steps. The first
-  step is to replace `use Mix.Config` at the top of your config files by
-  `import Config`.
-
-  The second is to make sure your `import_config/1` calls do not have a
-  wildcard character. If so, you need to perform the wildcard lookup
-  manually. For example, if you did:
-
-      import_config "../apps/*/config/config.exs"
-
-  It has to be replaced by:
-
-      for config <- "../apps/*/config/config.exs" |> Path.expand(__DIR__) |> Path.wildcard() do
-        import_config config
-      end
-
-  The last step is to replace all `Mix.env()` calls in the config files with `config_env()`.
-
-  Keep in mind you must also avoid using `Mix.env()` inside your project files.
-  To check the environment at _runtime_, you may add a configuration key:
-
-      # config.exs
-      ...
-      config :my_app, env: config_env()
-
-  Then, in other scripts and modules, you may get the environment with
-  `Application.fetch_env!/2`:
-
-      # router.exs
-      ...
-      if Application.fetch_env!(:my_app, :env) == :prod do
-        ...
-      end
-
-  The only files where you may access functions from the `Mix` module are
-  the `mix.exs` file and inside custom Mix tasks, which always within the
-  `Mix.Tasks` namespace.
-
-  ## config/runtime.exs
-
-  For runtime configuration, you can use the `config/runtime.exs` file.
-  It is executed right before applications start in both Mix and releases
-  (assembled with `mix release`).
-  """
-
-  @opts_key {__MODULE__, :opts}
-  @config_key {__MODULE__, :config}
-  @imports_key {__MODULE__, :imports}
-
-  defp get_opts!(), do: Process.get(@opts_key) || raise_improper_use!()
-  defp put_opts(value), do: Process.put(@opts_key, value)
-  defp delete_opts(), do: Process.delete(@opts_key)
-
-  defp get_config!(), do: Process.get(@config_key) || raise_improper_use!()
-  defp put_config(value), do: Process.put(@config_key, value)
-  defp delete_config(), do: Process.delete(@config_key)
-
-  defp get_imports!(), do: Process.get(@imports_key) || raise_improper_use!()
-  defp put_imports(value), do: Process.put(@imports_key, value)
-  defp delete_imports(), do: Process.delete(@imports_key)
-
-  defp raise_improper_use!() do
-    raise "could not set configuration via Config. " <>
-            "This usually means you are trying to execute a configuration file " <>
-            "directly, instead of reading it with Config.Reader"
-  end
-
-  @doc """
-  Configures the given `root_key`.
-
-  Keyword lists are always deep-merged.
-
-  ## Examples
-
-  The given `opts` are merged into the existing configuration
-  for the given `root_key`. Conflicting keys are overridden by the
-  ones specified in `opts`, unless they are keywords, which are
-  deep merged recursively. For example, the application configuration
-  below
-
-      config :logger,
-        level: :warn,
-        backends: [:console]
-
-      config :logger,
-        level: :info,
-        truncate: 1024
-
-  will have a final configuration for `:logger` of:
-
-      [level: :info, backends: [:console], truncate: 1024]
-
-  """
-  @doc since: "1.9.0"
-  def config(root_key, opts) when is_atom(root_key) and is_list(opts) do
-    unless Keyword.keyword?(opts) do
-      raise ArgumentError, "config/2 expected a keyword list, got: #{inspect(opts)}"
-    end
-
-    get_config!()
-    |> __merge__([{root_key, opts}])
-    |> put_config()
-  end
-
-  @doc """
-  Configures the given `key` for the given `root_key`.
-
-  Keyword lists are always deep merged.
-
-  ## Examples
-
-  The given `opts` are merged into the existing values for `key`
-  in the given `root_key`. Conflicting keys are overridden by the
-  ones specified in `opts`, unless they are keywords, which are
-  deep merged recursively. For example, the application configuration
-  below
-
-      config :ecto, Repo,
-        log_level: :warn,
-        adapter: Ecto.Adapters.Postgres,
-        metadata: [read_only: true]
-
-      config :ecto, Repo,
-        log_level: :info,
-        pool_size: 10,
-        metadata: [replica: true]
-
-  will have a final value of the configuration for the `Repo`
-  key in the `:ecto` application of:
-
-      Application.get_env(:ecto, Repo)
-      #=> [
-      #=>   log_level: :info,
-      #=>   pool_size: 10,
-      #=>   adapter: Ecto.Adapters.Postgres,
-      #=>   metadata: [read_only: true, replica: true]
-      #=> ]
-
-  """
-  @doc since: "1.9.0"
-  def config(root_key, key, opts) when is_atom(root_key) and is_atom(key) do
-    get_config!()
-    |> __merge__([{root_key, [{key, opts}]}])
-    |> put_config()
-  end
-
-  @doc """
-  Returns the environment this configuration file is executed on.
-
-  In Mix projects this function returns the environment this configuration
-  file is executed on. In releases, the environment when `mix release` ran.
-
-  This is most often used to execute conditional code:
-
-      if config_env() == :prod do
-        config :my_app, :debug, false
-      end
-
-  """
-  @doc since: "1.11.0"
-  defmacro config_env() do
-    quote do
-      Config.__env__!()
-    end
-  end
-
-  @doc false
-  @spec __env__!() :: atom()
-  def __env__!() do
-    elem(get_opts!(), 0) || raise "no :env key was given to this configuration file"
-  end
-
-  @doc """
-  Returns the target this configuration file is executed on.
-
-  This is most often used to execute conditional code:
-
-      if config_target() == :host do
-        config :my_app, :debug, false
-      end
-
-  """
-  @doc since: "1.11.0"
-  defmacro config_target() do
-    quote do
-      Config.__target__!()
-    end
-  end
-
-  @doc false
-  @spec __target__!() :: atom()
-  def __target__!() do
-    elem(get_opts!(), 1) || raise "no :target key was given to this configuration file"
-  end
-
-  @doc ~S"""
-  Imports configuration from the given file.
-
-  In case the file doesn't exist, an error is raised.
-
-  If file is a relative, it will be expanded relatively to the
-  directory the current configuration file is in.
-
-  ## Examples
-
-  This is often used to emulate configuration across environments:
-
-      import_config "#{config_env()}.exs"
-
-  Note, however, some configuration files, such as `config/runtime.exs`
-  does not support imports, as they are meant to be copied across
-  systems.
-  """
-  @doc since: "1.9.0"
-  defmacro import_config(file) do
-    quote do
-      Config.__import__!(Path.expand(unquote(file), __DIR__))
-      :ok
-    end
-  end
-
-  @doc false
-  @spec __import__!(Path.t()) :: {term, Code.binding()}
-  def __import__!(file) when is_binary(file) do
-    import_config!(file, File.read!(file), true)
-  end
-
-  @doc false
-  @spec __eval__!(Path.t(), binary(), keyword) :: {keyword, [Path.t()] | :disabled}
-  def __eval__!(file, content, opts \\ []) when is_binary(file) and is_list(opts) do
-    env = Keyword.get(opts, :env)
-    target = Keyword.get(opts, :target)
-    imports = Keyword.get(opts, :imports, [])
-
-    previous_opts = put_opts({env, target})
-    previous_config = put_config([])
-    previous_imports = put_imports(imports)
-
-    try do
-      {eval_config, _} = import_config!(file, content, false)
-
-      case get_config!() do
-        [] when is_list(eval_config) ->
-          {validate!(eval_config, file), get_imports!()}
-
-        pdict_config ->
-          {pdict_config, get_imports!()}
-      end
-    after
-      if previous_opts, do: put_opts(previous_opts), else: delete_opts()
-      if previous_config, do: put_config(previous_config), else: delete_config()
-      if previous_imports, do: put_imports(previous_imports), else: delete_imports()
-    end
-  end
-
-  defp import_config!(file, contents, raise_when_disabled?) do
-    current_imports = get_imports!()
-
-    cond do
-      current_imports == :disabled ->
-        if raise_when_disabled? do
-          raise "import_config/1 is not enabled for this configuration file. " <>
-                  "Some configuration files do not allow importing other files " <>
-                  "as they are often copied to external systems"
-        end
-
-      file in current_imports ->
-        raise ArgumentError,
-              "attempting to load configuration #{Path.relative_to_cwd(file)} recursively"
-
-      true ->
-        put_imports([file | current_imports])
-        :ok
-    end
-
-    Code.eval_string(contents, [], file: file)
-  end
-
-  @doc false
-  def __merge__(config1, config2) when is_list(config1) and is_list(config2) do
-    Keyword.merge(config1, config2, fn _, app1, app2 ->
-      Keyword.merge(app1, app2, &deep_merge/3)
-    end)
-  end
-
-  defp deep_merge(_key, value1, value2) do
-    if Keyword.keyword?(value1) and Keyword.keyword?(value2) do
-      Keyword.merge(value1, value2, &deep_merge/3)
-    else
-      value2
-    end
-  end
-
-  defp validate!(config, file) do
-    Enum.all?(config, fn
-      {app, value} when is_atom(app) ->
-        if Keyword.keyword?(value) do
-          true
-        else
-          raise ArgumentError,
-                "expected config for app #{inspect(app)} in #{Path.relative_to_cwd(file)} " <>
-                  "to return keyword list, got: #{inspect(value)}"
-        end
-
-      _ ->
-        false
-    end)
-
-    config
-  end
-end

lib/elixir/lib/config/provider.ex

@@ -1,415 +0,0 @@
-defmodule Config.Provider do
-  @moduledoc """
-  Specifies a provider API that loads configuration during boot.
-
-  Config providers are typically used during releases to load
-  external configuration while the system boots. This is done
-  by starting the VM with the minimum amount of applications
-  running, then invoking all of the providers, and then
-  restarting the system. This requires a mutable configuration
-  file on disk, as the results of the providers are written to
-  the file system. For more information on runtime configuration,
-  see `mix release`.
-
-  ## Multiple config files
-
-  One common use of config providers is to specify multiple
-  configuration files in a release. Elixir ships with one provider,
-  called `Config.Reader`, which is capable of handling Elixir's
-  built-in config files.
-
-  For example, imagine you want to list some basic configuration
-  on Mix's built-in `config/runtime.exs` file, but you also want
-  to support additional configuration files. To do so, you can add
-  this inside the `def project` portion of  your `mix.exs`:
-
-      releases: [
-        demo: [
-          config_providers: [
-            {Config.Reader, {:system, "RELEASE_ROOT", "/extra_config.exs"}}
-          ]
-        ]
-      ]
-
-  You can place this `extra_config.exs` file in your release in
-  multiple ways:
-
-    1. If it is available on the host when assembling the release,
-      you can place it on "rel/overlays/extra_config.exs" and it
-      will be automatically copied to the release root
-
-    2. If it is available on the target during deployment, you can
-      simply copy it to the release root as a step in your deployment
-
-  Now once the system boots, it will load both `config/runtime.exs`
-  and `extra_config.exs` early in the boot process. You can learn
-  more options on `Config.Reader`.
-
-  ## Custom config provider
-
-  You can also implement custom config providers, similar to how
-  `Config.Reader` works. For example, imagine you need to load
-  some configuration from a JSON file and load that into the system.
-  Said configuration provider would look like:
-
-      defmodule JSONConfigProvider do
-        @behaviour Config.Provider
-
-        # Let's pass the path to the JSON file as config
-        @impl true
-        def init(path) when is_binary(path), do: path
-
-        @impl true
-        def load(config, path) do
-          # We need to start any app we may depend on.
-          {:ok, _} = Application.ensure_all_started(:jason)
-
-          json = path |> File.read!() |> Jason.decode!()
-
-          Config.Reader.merge(
-            config,
-            my_app: [
-              some_value: json["my_app_some_value"],
-              another_value: json["my_app_another_value"],
-            ]
-          )
-        end
-      end
-
-  Then, when specifying your release, you can specify the provider in
-  the release configuration:
-
-      releases: [
-        demo: [
-          config_providers: [
-            {JSONConfigProvider, "/etc/config.json"}
-          ]
-        ]
-      ]
-
-  """
-
-  @type config :: keyword
-  @type state :: term
-
-  @typedoc """
-  A path pointing to a configuration file.
-
-  Since configuration files are often accessed on target machines,
-  it can be expressed either as:
-
-    * a binary representing an absolute path
-
-    * a `{:system, system_var, path}` tuple where the config is the
-      concatenation of the environment variable `system_var` with
-      the given `path`
-
-  """
-  @type config_path :: {:system, binary(), binary()} | binary()
-
-  @doc """
-  Invoked when initializing a config provider.
-
-  A config provider is typically initialized on the machine
-  where the system is assembled and not on the target machine.
-  The `c:init/1` callback is useful to verify the arguments
-  given to the provider and prepare the state that will be
-  given to `c:load/2`.
-
-  Furthermore, because the state returned by `c:init/1` can
-  be written to text-based config files, it should be
-  restricted only to simple data types, such as integers,
-  strings, atoms, tuples, maps, and lists. Entries such as
-  PIDs, references, and functions cannot be serialized.
-  """
-  @callback init(term) :: state
-
-  @doc """
-  Loads configuration (typically during system boot).
-
-  It receives the current `config` and the `state` returned by
-  `c:init/1`. Then, you typically read the extra configuration
-  from an external source and merge it into the received `config`.
-  Merging should be done with `Config.Reader.merge/2`, as it
-  performs deep merge. It should return the updated config.
-
-  Note that `c:load/2` is typically invoked very early in the
-  boot process, therefore if you need to use an application
-  in the provider, it is your responsibility to start it.
-  """
-  @callback load(config, state) :: config
-
-  @doc false
-  defstruct [
-    :providers,
-    :config_path,
-    extra_config: [],
-    prune_runtime_sys_config_after_boot: false,
-    reboot_system_after_config: false,
-    validate_compile_env: false
-  ]
-
-  @reserved_apps [:kernel, :stdlib]
-
-  @doc """
-  Validates a `t:config_path/0`.
-  """
-  @doc since: "1.9.0"
-  @spec validate_config_path!(config_path) :: :ok
-  def validate_config_path!({:system, name, path})
-      when is_binary(name) and is_binary(path),
-      do: :ok
-
-  def validate_config_path!(path) do
-    if is_binary(path) and Path.type(path) != :relative do
-      :ok
-    else
-      raise ArgumentError, """
-      expected configuration path to be:
-
-        * a binary representing an absolute path
-        * a tuple {:system, system_var, path} where the config is the \
-      concatenation of the `system_var` with the given `path`
-
-      Got: #{inspect(path)}
-      """
-    end
-  end
-
-  @doc """
-  Resolves a `t:config_path/0` to an actual path.
-  """
-  @doc since: "1.9.0"
-  @spec resolve_config_path!(config_path) :: binary
-  def resolve_config_path!(path) when is_binary(path), do: path
-  def resolve_config_path!({:system, name, path}), do: System.fetch_env!(name) <> path
-
-  # Private keys
-  @init_key :config_provider_init
-  @booted_key :config_provider_booted
-
-  # Public keys
-  @reboot_mode_key :config_provider_reboot_mode
-
-  @doc false
-  def init(providers, config_path, opts \\ []) when is_list(providers) and is_list(opts) do
-    validate_config_path!(config_path)
-    providers = for {provider, init} <- providers, do: {provider, provider.init(init)}
-    init = struct!(%Config.Provider{config_path: config_path, providers: providers}, opts)
-    [elixir: [{@init_key, init}]]
-  end
-
-  @doc false
-  def boot(reboot_fun \\ &restart_and_sleep/0) do
-    # The config provider typically runs very early in the
-    # release process, so we need to make sure Elixir is started
-    # before we go around running Elixir code.
-    {:ok, _} = :application.ensure_all_started(:elixir)
-
-    case Application.fetch_env(:elixir, @booted_key) do
-      {:ok, {:booted, path}} ->
-        path && File.rm(path)
-
-        with {:ok, %Config.Provider{} = provider} <- Application.fetch_env(:elixir, @init_key) do
-          maybe_validate_compile_env(provider)
-        end
-
-        :booted
-
-      _ ->
-        case Application.fetch_env(:elixir, @init_key) do
-          {:ok, %Config.Provider{} = provider} ->
-            path = resolve_config_path!(provider.config_path)
-            reboot_config = [elixir: [{@booted_key, booted_value(provider, path)}]]
-            boot_providers(path, provider, reboot_config, reboot_fun)
-
-          _ ->
-            :skip
-        end
-    end
-  end
-
-  defp boot_providers(path, provider, reboot_config, reboot_fun) do
-    original_config = read_config!(path)
-
-    config =
-      original_config
-      |> Config.__merge__(provider.extra_config)
-      |> run_providers(provider)
-
-    if provider.reboot_system_after_config do
-      config
-      |> Config.__merge__(reboot_config)
-      |> write_config!(path)
-
-      reboot_fun.()
-    else
-      for app <- @reserved_apps, config[app] != original_config[app] do
-        abort("""
-        Cannot configure #{inspect(app)} because :reboot_system_after_config has been set \
-        to false and #{inspect(app)} has already been loaded, meaning any further \
-        configuration won't have an effect.
-
-        The configuration for #{inspect(app)} before config providers was:
-
-        #{inspect(original_config[app])}
-
-        The configuration for #{inspect(app)} after config providers was:
-
-        #{inspect(config[app])}
-        """)
-      end
-
-      _ = Application.put_all_env(config, persistent: true)
-      maybe_validate_compile_env(provider)
-      :ok
-    end
-  end
-
-  defp maybe_validate_compile_env(provider) do
-    with [_ | _] = compile_env <- provider.validate_compile_env do
-      validate_compile_env(compile_env)
-    end
-  end
-
-  @doc false
-  def validate_compile_env(compile_env, ensure_loaded? \\ true) do
-    for {app, [key | path], compile_return} <- compile_env,
-        ensure_app_loaded?(app, ensure_loaded?) do
-      try do
-        traverse_env(Application.fetch_env(app, key), path)
-      rescue
-        e ->
-          abort("""
-          application #{inspect(app)} failed reading its compile environment #{path(key, path)}:
-
-          #{Exception.format(:error, e, __STACKTRACE__)}
-
-          Expected it to match the compile time value of #{return_to_text(compile_return)}.
-
-          #{compile_env_tips(app)}
-          """)
-      else
-        ^compile_return ->
-          :ok
-
-        runtime_return ->
-          abort("""
-          the application #{inspect(app)} has a different value set #{path(key, path)} \
-          during runtime compared to compile time. Since this application environment entry was \
-          marked as compile time, this difference can lead to different behaviour than expected:
-
-            * Compile time value #{return_to_text(compile_return)}
-            * Runtime value #{return_to_text(runtime_return)}
-
-          #{compile_env_tips(app)}
-          """)
-      end
-    end
-
-    :ok
-  end
-
-  defp ensure_app_loaded?(app, true), do: Application.ensure_loaded(app) == :ok
-  defp ensure_app_loaded?(app, false), do: Application.spec(app, :vsn) != nil
-
-  defp path(key, []), do: "for key #{inspect(key)}"
-  defp path(key, path), do: "for path #{inspect(path)} inside key #{inspect(key)}"
-
-  defp compile_env_tips(app),
-    do: """
-    To fix this error, you might:
-
-      * Make the runtime value match the compile time one
-
-      * Recompile your project. If the misconfigured application is a dependency, \
-    you may need to run "mix deps.compile #{app} --force"
-
-      * Alternatively, you can disable this check. If you are using releases, you can \
-    set :validate_compile_env to false in your release configuration. If you are \
-    using Mix to start your system, you can pass the --no-validate-compile-env flag
-    """
-
-  defp return_to_text({:ok, value}), do: "was set to: #{inspect(value)}"
-  defp return_to_text(:error), do: "was not set"
-
-  defp traverse_env(return, []), do: return
-  defp traverse_env(:error, _paths), do: :error
-  defp traverse_env({:ok, value}, [key | keys]), do: traverse_env(Access.fetch(value, key), keys)
-
-  @compile {:no_warn_undefined, {:init, :restart, 1}}
-  defp restart_and_sleep() do
-    mode = Application.get_env(:elixir, @reboot_mode_key)
-
-    if mode in [:embedded, :interactive] do
-      :init.restart(mode: mode)
-    else
-      :init.restart()
-    end
-
-    Process.sleep(:infinity)
-  end
-
-  defp booted_value(%{prune_runtime_sys_config_after_boot: true}, path), do: {:booted, path}
-  defp booted_value(%{prune_runtime_sys_config_after_boot: false}, _path), do: {:booted, nil}
-
-  defp read_config!(path) do
-    case :file.consult(path) do
-      {:ok, [inner]} ->
-        inner
-
-      {:error, reason} ->
-        bad_path_abort(
-          "Could not read runtime configuration due to reason: #{inspect(reason)}",
-          path
-        )
-    end
-  end
-
-  defp run_providers(config, %{providers: providers}) do
-    Enum.reduce(providers, config, fn {provider, state}, acc ->
-      try do
-        provider.load(acc, state)
-      catch
-        kind, error ->
-          IO.puts(:stderr, "ERROR! Config provider #{inspect(provider)} failed with:")
-          IO.puts(:stderr, Exception.format(kind, error, __STACKTRACE__))
-          :erlang.raise(kind, error, __STACKTRACE__)
-      else
-        term when is_list(term) ->
-          term
-
-        term ->
-          abort("Expected provider #{inspect(provider)} to return a list, got: #{inspect(term)}")
-      end
-    end)
-  end
-
-  defp write_config!(config, path) do
-    contents = :io_lib.format("%% coding: utf-8~n~tw.~n", [config])
-
-    case File.write(path, IO.chardata_to_string(contents)) do
-      :ok ->
-        :ok
-
-      {:error, reason} ->
-        bad_path_abort(
-          "Could not write runtime configuration due to reason: #{inspect(reason)}",
-          path
-        )
-    end
-  end
-
-  defp bad_path_abort(msg, path) do
-    abort(
-      msg <>
-        ". Please make sure #{inspect(path)} is writable and accessible " <>
-        "or choose a different path"
-    )
-  end
-
-  defp abort(msg) do
-    IO.puts("ERROR! " <> msg)
-    :erlang.raise(:error, "aborting boot", [{Config.Provider, :boot, 2, []}])
-  end
-end

lib/elixir/lib/config/reader.ex

@@ -1,138 +0,0 @@
-defmodule Config.Reader do
-  @moduledoc """
-  API for reading config files defined with `Config`.
-
-  ## As a provider
-
-  `Config.Reader` can also be used as a `Config.Provider`. A config
-  provider is used during releases to customize how applications are
-  configured. When used as a provider, it expects a single argument:
-  the configuration path (as outlined in `t:Config.Provider.config_path/0`)
-  for the file to be read and loaded during the system boot.
-
-  For example, if you expect the target system to have a config file
-  in an absolute path, you can add this inside the `def project` portion
-  of  your `mix.exs`:
-
-      releases: [
-        demo: [
-          config_providers: [
-            {Config.Reader, "/etc/config.exs"}
-          ]
-        ]
-      ]
-
-  Or if you want to read a custom path inside the release:
-
-      config_providers: [{Config.Reader, {:system, "RELEASE_ROOT", "/config.exs"}}]
-
-  You can also pass a keyword list of options to the reader,
-  where the `:path` is a required key:
-
-      config_providers: [
-        {Config.Reader,
-         path: "/etc/config.exs",
-         env: :prod,
-         imports: :disabled}
-      ]
-
-  Remember Mix already loads `config/runtime.exs` by default.
-  For more examples and scenarios, see the `Config.Provider` module.
-  """
-
-  @behaviour Config.Provider
-
-  @impl true
-  def init(opts) when is_list(opts) do
-    {path, opts} = Keyword.pop!(opts, :path)
-    Config.Provider.validate_config_path!(path)
-    {path, opts}
-  end
-
-  def init(path) do
-    init(path: path)
-  end
-
-  @impl true
-  def load(config, {path, opts}) do
-    merge(config, path |> Config.Provider.resolve_config_path!() |> read!(opts))
-  end
-
-  @doc """
-  Evaluates the configuration `contents` for the given `file`.
-
-  Accepts the same options as `read!/2`.
-  """
-  @doc since: "1.11.0"
-  @spec eval!(Path.t(), binary, keyword) :: keyword
-  def eval!(file, contents, opts \\ [])
-      when is_binary(file) and is_binary(contents) and is_list(opts) do
-    Config.__eval__!(Path.expand(file), contents, opts) |> elem(0)
-  end
-
-  @doc """
-  Reads the configuration file.
-
-  ## Options
-
-    * `:imports` - a list of already imported paths or `:disabled`
-      to disable imports
-
-    * `:env` - the environment the configuration file runs on.
-      See `Config.config_env/0` for sample usage
-
-    * `:target` - the target the configuration file runs on.
-      See `Config.config_target/0` for sample usage
-
-  """
-  @doc since: "1.9.0"
-  @spec read!(Path.t(), keyword) :: keyword
-  def read!(file, opts \\ []) when is_binary(file) and is_list(opts) do
-    file = Path.expand(file)
-    Config.__eval__!(file, File.read!(file), opts) |> elem(0)
-  end
-
-  @doc """
-  Reads the given configuration file and returns the configuration
-  with its imports.
-
-  Accepts the same options as `read!/2`. Although note the `:imports`
-  option cannot be disabled in `read_imports!/2`.
-  """
-  @doc since: "1.9.0"
-  @spec read_imports!(Path.t(), keyword) :: {keyword, [Path.t()]}
-  def read_imports!(file, opts \\ []) when is_binary(file) and is_list(opts) do
-    if opts[:imports] == :disabled do
-      raise ArgumentError, ":imports must be a list of paths"
-    end
-
-    file = Path.expand(file)
-    Config.__eval__!(file, File.read!(file), opts)
-  end
-
-  @doc """
-  Merges two configurations.
-
-  The configurations are merged together with the values in
-  the second one having higher preference than the first in
-  case of conflicts. In case both values are set to keyword
-  lists, it deep merges them.
-
-  ## Examples
-
-      iex> Config.Reader.merge([app: [k: :v1]], [app: [k: :v2]])
-      [app: [k: :v2]]
-
-      iex> Config.Reader.merge([app: [k: [v1: 1, v2: 2]]], [app: [k: [v2: :a, v3: :b]]])
-      [app: [k: [v1: 1, v2: :a, v3: :b]]]
-
-      iex> Config.Reader.merge([app1: []], [app2: []])
-      [app1: [], app2: []]
-
-  """
-  @doc since: "1.9.0"
-  @spec merge(keyword, keyword) :: keyword
-  def merge(config1, config2) when is_list(config1) and is_list(config2) do
-    Config.__merge__(config1, config2)
-  end
-end

lib/elixir/lib/dict.ex

@@ -18,14 +18,13 @@ defmodule Dict do
   message =
     "Use the Map module for working with maps or the Keyword module for working with keyword lists"
 
+  # TODO: Remove by 2.0
+
+  @deprecated message
   defmacro __using__(_) do
     # Use this import to guarantee proper code expansion
     import Kernel, except: [size: 1]
 
-    if __CALLER__.module != HashDict do
-      IO.warn("use Dict is deprecated. " <> unquote(message), __CALLER__)
-    end
-
     quote do
       message = "Use maps and the Map module instead"
 
@@ -155,13 +154,13 @@ defmodule Dict do
       end
 
       @deprecated message
-      def update(dict, key, default, fun) do
+      def update(dict, key, initial, fun) do
         case fetch(dict, key) do
           {:ok, value} ->
             put(dict, key, fun.(value))
 
           :error ->
-            put(dict, key, default)
+            put(dict, key, initial)
         end
       end
 
@@ -296,7 +295,7 @@ defmodule Dict do
   end
 
   @deprecated message
-  @spec fetch!(t, key) :: value
+  @spec fetch!(t, key) :: value | no_return
   def fetch!(dict, key) do
     target(dict).fetch!(dict, key)
   end
@@ -378,8 +377,8 @@ defmodule Dict do
 
   @deprecated message
   @spec update(t, key, value, (value -> value)) :: t
-  def update(dict, key, default, fun) do
-    target(dict).update(dict, key, default, fun)
+  def update(dict, key, initial, fun) do
+    target(dict).update(dict, key, initial, fun)
   end
 
   @deprecated message

lib/elixir/lib/dynamic_supervisor.ex

@@ -1,21 +1,22 @@
 defmodule DynamicSupervisor do
   @moduledoc ~S"""
-  A supervisor optimized to only start children dynamically.
+  A supervisor that starts children dynamically.
 
   The `Supervisor` module was designed to handle mostly static children
   that are started in the given order when the supervisor starts. A
   `DynamicSupervisor` starts with no children. Instead, children are
-  started on demand via `start_child/2` and there is no ordering between
-  children. This allows the `DynamicSupervisor` to hold millions of
-  children by using efficient data structures and to execute certain
-  operations, such as shutting down, concurrently.
+  started on demand via `start_child/2`. When a dynamic supervisor
+  terminates, all children are shutdown at the same time, with no guarantee
+  of ordering.
 
   ## Examples
 
-  A dynamic supervisor is started with no children and often a name:
+  A dynamic supervisor is started with no children, often under a
+  supervisor with the supervision strategy (the only strategy currently
+  supported is `:one_for_one`) and a name:
 
       children = [
-        {DynamicSupervisor, name: MyApp.DynamicSupervisor}
+        {DynamicSupervisor, strategy: :one_for_one, name: MyApp.DynamicSupervisor}
       ]
 
       Supervisor.start_link(children, strategy: :one_for_one)
@@ -37,46 +38,6 @@ defmodule DynamicSupervisor do
       DynamicSupervisor.count_children(MyApp.DynamicSupervisor)
       #=> %{active: 2, specs: 2, supervisors: 0, workers: 2}
 
-  ## Scalability and partitioning
-
-  The `DynamicSupervisor` is a single process responsible for starting
-  other processes. In some applications, the `DynamicSupervisor` may
-  become a bottleneck. To address this, you can start multiple instances
-  of the `DynamicSupervisor` and then pick a "random" instance to start
-  the child on.
-
-  Instead of:
-
-      children = [
-        {DynamicSupervisor, name: MyApp.DynamicSupervisor}
-      ]
-
-  and:
-
-      DynamicSupervisor.start_child(MyApp.DynamicSupervisor, {Agent, fn -> %{} end})
-
-  You can do this:
-
-      children = [
-        {PartitionSupervisor,
-         child_spec: DynamicSupervisor,
-         name: MyApp.DynamicSupervisors}
-      ]
-
-  and then:
-
-      DynamicSupervisor.start_child(
-        {:via, PartitionSupervisor, {MyApp.DynamicSupervisors, self()}},
-        {Agent, fn -> %{} end}
-      )
-
-  In the code above, we start a partition supervisor that will by default
-  start a dynamic supervisor for each core in your machine. Then, instead
-  of calling the `DynamicSupervisor` by name, you call it through the
-  partition supervisor, using `self()` as the routing key. This means each
-  process will be assigned one of the existing dynamic supervisors.
-  Read the `PartitionSupervisor` docs for more information.
-
   ## Module-based supervisors
 
   Similar to `Supervisor`, dynamic supervisors also support module-based
@@ -86,20 +47,18 @@ defmodule DynamicSupervisor do
         # Automatically defines child_spec/1
         use DynamicSupervisor
 
-        def start_link(init_arg) do
-          DynamicSupervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
+        def start_link(arg) do
+          DynamicSupervisor.start_link(__MODULE__, arg, name: __MODULE__)
         end
 
         @impl true
-        def init(_init_arg) do
+        def init(_arg) do
           DynamicSupervisor.init(strategy: :one_for_one)
         end
       end
 
   See the `Supervisor` docs for a discussion of when you may want to use
-  module-based supervisors. A `@doc` annotation immediately preceding
-  `use DynamicSupervisor` will be attached to the generated `child_spec/1`
-  function.
+  module-based supervisors.
 
   ## Name registration
 
@@ -117,20 +76,20 @@ defmodule DynamicSupervisor do
       defmodule MySupervisor do
         use Supervisor
 
-        def start_link(init_arg) do
-          Supervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
+        def start_link(arg) do
+          Supervisor.start_link(__MODULE__, arg, name: __MODULE__)
         end
 
         def start_child(foo, bar, baz) do
-          # This will start child by calling MyWorker.start_link(init_arg, foo, bar, baz)
+          # This will start child by calling MyWorker.start_link(initial_arg, foo, bar, baz)
           Supervisor.start_child(__MODULE__, [foo, bar, baz])
         end
 
         @impl true
-        def init(init_arg) do
+        def init(initial_arg) do
           children = [
-            # Or the deprecated: worker(MyWorker, [init_arg])
-            %{id: MyWorker, start: {MyWorker, :start_link, [init_arg]}}
+            # Or the deprecated: worker(MyWorker, [initial_arg])
+            %{id: MyWorker, start: {MyWorker, :start_link, [initial_arg]})
           ]
 
           Supervisor.init(children, strategy: :simple_one_for_one)
@@ -142,8 +101,8 @@ defmodule DynamicSupervisor do
       defmodule MySupervisor do
         use DynamicSupervisor
 
-        def start_link(init_arg) do
-          DynamicSupervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
+        def start_link(arg) do
+          DynamicSupervisor.start_link(__MODULE__, arg, name: __MODULE__)
         end
 
         def start_child(foo, bar, baz) do
@@ -154,10 +113,10 @@ defmodule DynamicSupervisor do
         end
 
         @impl true
-        def init(init_arg) do
+        def init(initial_arg) do
           DynamicSupervisor.init(
             strategy: :one_for_one,
-            extra_arguments: [init_arg]
+            extra_arguments: [initial_arg]
           )
         end
       end
@@ -176,7 +135,7 @@ defmodule DynamicSupervisor do
   Developers typically invoke `DynamicSupervisor.init/1` at the end of
   their init callback to return the proper supervision flags.
   """
-  @callback init(init_arg :: term) :: {:ok, sup_flags()} | :ignore
+  @callback init(args :: term) :: {:ok, sup_flags()} | :ignore
 
   @typedoc "The supervisor flags returned on init"
   @type sup_flags() :: %{
@@ -187,10 +146,13 @@ defmodule DynamicSupervisor do
           extra_arguments: [term()]
         }
 
-  @typedoc "Options given to `start_link` functions"
-  @type option :: GenServer.option()
+  @typedoc "Option values used by the `start*` functions"
+  @type option :: {:name, Supervisor.name()} | init_option()
 
-  @typedoc "Options given to `start_link` and `init/1` functions"
+  @typedoc "Options used by the `start*` functions"
+  @type options :: [option, ...]
+
+  @typedoc "Options given to `start_link/2` and `init/1`"
   @type init_option ::
           {:strategy, strategy()}
           | {:max_restarts, non_neg_integer()}
@@ -208,7 +170,6 @@ defmodule DynamicSupervisor do
           | :ignore
           | {:error, {:already_started, pid} | :max_children | term}
 
-  # In this struct, `args` refers to the arguments passed to init/1 (the `init_arg`).
   defstruct [
     :args,
     :extra_arguments,
@@ -247,14 +208,12 @@ defmodule DynamicSupervisor do
   defmacro __using__(opts) do
     quote location: :keep, bind_quoted: [opts: opts] do
       @behaviour DynamicSupervisor
-      unless Module.has_attribute?(__MODULE__, :doc) do
-        @doc """
-        Returns a specification to start this module under a supervisor.
 
-        See `Supervisor`.
-        """
-      end
+      @doc """
+      Returns a specification to start this module under a supervisor.
 
+      See `Supervisor`.
+      """
       def child_spec(arg) do
         default = %{
           id: __MODULE__,
@@ -272,74 +231,12 @@ defmodule DynamicSupervisor do
   @doc """
   Starts a supervisor with the given options.
 
-  This function is typically not invoked directly, instead it is invoked
-  when using a `DynamicSupervisor` as a child of another supervisor:
+  The `:strategy` is a required option and the currently supported
+  value is `:one_for_one`. The remaining options can be found in the
+  `init/1` docs.
 
-      children = [
-        {DynamicSupervisor, name: MySupervisor}
-      ]
-
-  If the supervisor is successfully spawned, this function returns
-  `{:ok, pid}`, where `pid` is the PID of the supervisor. If the supervisor
-  is given a name and a process with the specified name already exists,
-  the function returns `{:error, {:already_started, pid}}`, where `pid`
-  is the PID of that process.
-
-  Note that a supervisor started with this function is linked to the parent
-  process and exits not only on crashes but also if the parent process exits
-  with `:normal` reason.
-
-  ## Options
-
-    * `:name` - registers the supervisor under the given name.
-      The supported values are described under the "Name registration"
-      section in the `GenServer` module docs.
-
-    * `:strategy` - the restart strategy option. The only supported
-      value is `:one_for_one` which means that no other child is
-      terminated if a child process terminates. You can learn more
-      about strategies in the `Supervisor` module docs.
-
-    * `:max_restarts` - the maximum number of restarts allowed in
-      a time frame. Defaults to `3`.
-
-    * `:max_seconds` - the time frame in which `:max_restarts` applies.
-      Defaults to `5`.
-
-    * `:max_children` - the maximum amount of children to be running
-      under this supervisor at the same time. When `:max_children` is
-      exceeded, `start_child/2` returns `{:error, :max_children}`. Defaults
-      to `:infinity`.
-
-    * `:extra_arguments` - arguments that are prepended to the arguments
-      specified in the child spec given to `start_child/2`. Defaults to
-      an empty list.
-
-  """
-  @doc since: "1.6.0"
-  @spec start_link([option | init_option]) :: Supervisor.on_start()
-  def start_link(options) when is_list(options) do
-    keys = [:extra_arguments, :max_children, :max_seconds, :max_restarts, :strategy]
-    {sup_opts, start_opts} = Keyword.split(options, keys)
-    start_link(Supervisor.Default, init(sup_opts), start_opts)
-  end
-
-  @doc """
-  Starts a module-based supervisor process with the given `module` and `init_arg`.
-
-  To start the supervisor, the `c:init/1` callback will be invoked in the given
-  `module`, with `init_arg` as its argument. The `c:init/1` callback must return a
-  supervisor specification which can be created with the help of the `init/1`
-  function.
-
-  If the `c:init/1` callback returns `:ignore`, this function returns
-  `:ignore` as well and the supervisor terminates with reason `:normal`.
-  If it fails or returns an incorrect value, this function returns
-  `{:error, term}` where `term` is a term with information about the
-  error, and the supervisor terminates with reason `term`.
-
-  The `:name` option can also be given in order to register a supervisor
-  name, the supported values are described in the "Name registration"
+  The `:name` option can also be used to register a supervisor name.
+  The supported values are described under the "Name registration"
   section in the `GenServer` module docs.
 
   If the supervisor is successfully spawned, this function returns
@@ -353,19 +250,43 @@ defmodule DynamicSupervisor do
   with `:normal` reason.
   """
   @doc since: "1.6.0"
-  @spec start_link(module, term, [option]) :: Supervisor.on_start()
-  def start_link(module, init_arg, opts \\ []) do
-    GenServer.start_link(__MODULE__, {module, init_arg, opts[:name]}, opts)
+  @spec start_link(options) :: Supervisor.on_start()
+  def start_link(options) when is_list(options) do
+    keys = [:extra_arguments, :max_children, :max_seconds, :max_restarts, :strategy]
+    {sup_opts, start_opts} = Keyword.split(options, keys)
+    start_link(Supervisor.Default, init(sup_opts), start_opts)
+  end
+
+  @doc """
+  Starts a module-based supervisor process with the given `module` and `arg`.
+
+  To start the supervisor, the `c:init/1` callback will be invoked in the given
+  `module`, with `arg` as its argument. The `c:init/1` callback must return a
+  supervisor specification which can be created with the help of the `init/1`
+  function.
+
+  If the `c:init/1` callback returns `:ignore`, this function returns
+  `:ignore` as well and the supervisor terminates with reason `:normal`.
+  If it fails or returns an incorrect value, this function returns
+  `{:error, term}` where `term` is a term with information about the
+  error, and the supervisor terminates with reason `term`.
+
+  The `:name` option can also be given in order to register a supervisor
+  name, the supported values are described in the "Name registration"
+  section in the `GenServer` module docs.
+  """
+  @doc since: "1.6.0"
+  @spec start_link(module, term, GenServer.options()) :: Supervisor.on_start()
+  def start_link(mod, args, opts \\ []) do
+    GenServer.start_link(__MODULE__, {mod, args, opts[:name]}, opts)
   end
 
   @doc """
   Dynamically adds a child specification to `supervisor` and starts that child.
 
   `child_spec` should be a valid child specification as detailed in the
-  "Child specification" section of the documentation for `Supervisor`. The child
-  process will be started as defined in the child specification. Note that while
-  the `:id` field is still required in the spec, the value is ignored and
-  therefore does not need to be unique.
+  "child_spec/1" section of the documentation for `Supervisor`. The child
+  process will be started as defined in the child specification.
 
   If the child process start function returns `{:ok, child}` or `{:ok, child,
   info}`, then child specification and PID are added to the supervisor and
@@ -376,21 +297,15 @@ defmodule DynamicSupervisor do
 
   If the child process start function returns an error tuple or an erroneous
   value, or if it fails, the child specification is discarded and this function
-  returns `{:error, error}` where `error` is the error or erroneous value
-  returned from child process start function, or failure reason if it fails.
+  returns `{:error, error}` where `error` is a term containing information about
+  the error and child specification.
 
   If the supervisor already has N children in a way that N exceeds the amount
   of `:max_children` set on the supervisor initialization (see `init/1`), then
   this function returns `{:error, :max_children}`.
   """
   @doc since: "1.6.0"
-  @spec start_child(
-          Supervisor.supervisor(),
-          Supervisor.child_spec()
-          | {module, term}
-          | module
-          | (old_erlang_child_spec :: :supervisor.child_spec())
-        ) ::
+  @spec start_child(Supervisor.supervisor(), :supervisor.child_spec() | {module, term} | module) ::
           on_start_child()
   def start_child(supervisor, {_, _, _, _, _, _} = child_spec) do
     validate_and_start_child(supervisor, child_spec)
@@ -485,7 +400,7 @@ defmodule DynamicSupervisor do
 
     * `id` - it is always `:undefined` for dynamic supervisors
 
-    * `child` - the PID of the corresponding child process or the
+    * `child` - the pid of the corresponding child process or the
       atom `:restarting` if the process is about to be restarted
 
     * `type` - `:worker` or `:supervisor` as defined in the child
@@ -496,8 +411,7 @@ defmodule DynamicSupervisor do
   """
   @doc since: "1.6.0"
   @spec which_children(Supervisor.supervisor()) :: [
-          # module() | :dynamic here because :supervisor.modules() is not exported
-          {:undefined, pid | :restarting, :worker | :supervisor, [module()] | :dynamic}
+          {:undefined, pid | :restarting, :worker | :supervisor, :supervisor.modules()}
         ]
   def which_children(supervisor) do
     call(supervisor, :which_children)
@@ -548,26 +462,52 @@ defmodule DynamicSupervisor do
   end
 
   @doc """
-  Receives a set of `options` that initializes a dynamic supervisor.
+  Receives a set of options that initializes a dynamic supervisor.
 
   This is typically invoked at the end of the `c:init/1` callback of
-  module-based supervisors. See the "Module-based supervisors" section
+  module-based supervisors. See the sections "Module-based supervisors"
   in the module documentation for more information.
 
-  It accepts the same `options` as `start_link/1` (except for `:name`)
-  and it returns a tuple containing the supervisor options.
+  The options received by this function are also supported by `start_link/2`.
+
+  This function returns a tuple containing the supervisor options.
 
   ## Examples
 
       def init(_arg) do
-        DynamicSupervisor.init(max_children: 1000)
+        DynamicSupervisor.init(max_children: 1000, strategy: :one_for_one)
       end
 
+  ## Options
+
+    * `:strategy` - the restart strategy option. The only supported
+      value is `:one_for_one` which means that no other child is
+      terminate if a child process terminates. You can learn more
+      about strategies in the `Supervisor` module docs.
+
+    * `:max_restarts` - the maximum number of restarts allowed in
+      a time frame. Defaults to `3`.
+
+    * `:max_seconds` - the time frame in which `:max_restarts` applies.
+      Defaults to `5`.
+
+    * `:max_children` - the maximum amount of children to be running
+      under this supervisor at the same time. When `:max_children` is
+      exceeded, `start_child/2` returns `{:error, :max_children}`. Defaults
+      to `:infinity`.
+
+    * `:extra_arguments` - arguments that are prepended to the arguments
+      specified in the child spec given to `start_child/2`. Defaults to
+      an empty list.
+
   """
   @doc since: "1.6.0"
   @spec init([init_option]) :: {:ok, sup_flags()}
   def init(options) when is_list(options) do
-    strategy = Keyword.get(options, :strategy, :one_for_one)
+    unless strategy = options[:strategy] do
+      raise ArgumentError, "expected :strategy option to be given"
+    end
+
     intensity = Keyword.get(options, :max_restarts, 3)
     period = Keyword.get(options, :max_seconds, 5)
     max_children = Keyword.get(options, :max_children, :infinity)
@@ -587,11 +527,11 @@ defmodule DynamicSupervisor do
   ## Callbacks
 
   @impl true
-  def init({mod, init_arg, name}) do
+  def init({mod, args, name}) do
     Process.put(:"$initial_call", {:supervisor, mod, 1})
     Process.flag(:trap_exit, true)
 
-    case mod.init(init_arg) do
+    case mod.init(args) do
       {:ok, flags} when is_map(flags) ->
         name =
           cond do
@@ -600,7 +540,7 @@ defmodule DynamicSupervisor do
             is_tuple(name) -> name
           end
 
-        state = %DynamicSupervisor{mod: mod, args: init_arg, name: name}
+        state = %DynamicSupervisor{mod: mod, args: args, name: name}
 
         case init(state, flags) do
           {:ok, state} -> {:ok, state}
@@ -800,26 +740,13 @@ defmodule DynamicSupervisor do
   end
 
   def handle_info(msg, state) do
-    :logger.error(
-      %{
-        label: {DynamicSupervisor, :unexpected_msg},
-        report: %{
-          msg: msg
-        }
-      },
-      %{
-        domain: [:otp, :elixir],
-        error_logger: %{tag: :error_msg},
-        report_cb: &__MODULE__.format_report/1
-      }
-    )
-
+    :error_logger.error_msg('DynamicSupervisor received unexpected message: ~p~n', [msg])
     {:noreply, state}
   end
 
   @impl true
-  def code_change(_, %{mod: mod, args: init_arg} = state, _) do
-    case mod.init(init_arg) do
+  def code_change(_, %{mod: mod, args: args} = state, _) do
+    case mod.init(args) do
       {:ok, flags} when is_map(flags) ->
         case init(state, flags) do
           {:ok, state} -> {:ok, state}
@@ -1056,22 +983,12 @@ defmodule DynamicSupervisor do
   end
 
   defp report_error(error, reason, pid, child, %{name: name, extra_arguments: extra}) do
-    :logger.error(
-      %{
-        label: {:supervisor, error},
-        report: [
-          {:supervisor, name},
-          {:errorContext, error},
-          {:reason, reason},
-          {:offender, extract_child(pid, child, extra)}
-        ]
-      },
-      %{
-        domain: [:otp, :sasl],
-        report_cb: &:logger.format_otp_report/1,
-        logger_formatter: %{title: "SUPERVISOR REPORT"},
-        error_logger: %{tag: :error_report, type: :supervisor_report}
-      }
+    :error_logger.error_report(
+      :supervisor_report,
+      supervisor: name,
+      errorContext: error,
+      reason: reason,
+      offender: extract_child(pid, child, extra)
     )
   end
 
@@ -1102,12 +1019,4 @@ defmodule DynamicSupervisor do
   defp call(supervisor, req) do
     GenServer.call(supervisor, req, :infinity)
   end
-
-  @doc false
-  def format_report(%{
-        label: {__MODULE__, :unexpected_msg},
-        report: %{msg: msg}
-      }) do
-    {'DynamicSupervisor received unexpected message: ~p~n', [msg]}
-  end
 end

lib/elixir/lib/file/stat.ex

@@ -12,7 +12,7 @@ defmodule File.Stat do
 
     * `size` - size of file in bytes.
 
-    * `type` - `:device | :directory | :regular | :other | :symlink`; the type of the
+    * `type` - `:device | :directory | :regular | :other`; the type of the
       file.
 
     * `access` - `:read | :write | :read_write | :none`; the current system
@@ -23,7 +23,7 @@ defmodule File.Stat do
     * `mtime` - the last time the file was written.
 
     * `ctime` - the interpretation of this time field depends on the operating
-      system. On Unix-like operating systems, it is the last time the file or the inode was changed.
+      system. On Unix, it is the last time the file or the inode was changed.
       In Windows, it is the time of creation.
 
     * `mode` - the file permissions.
@@ -35,17 +35,17 @@ defmodule File.Stat do
       In Windows, the number indicates a drive as follows: 0 means A:, 1 means
       B:, and so on.
 
-    * `minor_device` - only valid for character devices on Unix-like systems. In all other
+    * `minor_device` - only valid for character devices on Unix. In all other
       cases, this field is zero.
 
-    * `inode` - gives the inode number. On non-Unix-like file systems, this field
+    * `inode` - gives the inode number. On non-Unix file systems, this field
       will be zero.
 
-    * `uid` - indicates the owner of the file. Will be zero for non-Unix-like file
+    * `uid` - indicates the owner of the file. Will be zero for non-Unix file
       systems.
 
     * `gid` - indicates the group that owns the file. Will be zero for
-      non-Unix-like file systems.
+      non-Unix file systems.
 
   The time type returned in `atime`, `mtime`, and `ctime` is dependent on the
   time type set in options. `{:time, type}` where type can be `:local`,
@@ -58,27 +58,11 @@ defmodule File.Stat do
   pairs = :lists.zip(keys, vals)
 
   defstruct keys
-
-  @type t :: %__MODULE__{
-          size: non_neg_integer(),
-          type: :device | :directory | :regular | :other | :symlink,
-          access: :read | :write | :read_write | :none,
-          atime: :calendar.datetime() | integer(),
-          mtime: :calendar.datetime() | integer(),
-          ctime: :calendar.datetime() | integer(),
-          mode: non_neg_integer(),
-          links: non_neg_integer(),
-          major_device: non_neg_integer(),
-          minor_device: non_neg_integer(),
-          inode: non_neg_integer(),
-          uid: non_neg_integer(),
-          gid: non_neg_integer()
-        }
+  @type t :: %__MODULE__{}
 
   @doc """
   Converts a `File.Stat` struct to a `:file_info` record.
   """
-  @spec to_record(t()) :: :file.file_info()
   def to_record(%File.Stat{unquote_splicing(pairs)}) do
     {:file_info, unquote_splicing(vals)}
   end
@@ -86,7 +70,6 @@ defmodule File.Stat do
   @doc """
   Converts a `:file_info` record into a `File.Stat`.
   """
-  @spec from_record(:file.file_info()) :: t()
   def from_record(file_info)
 
   def from_record({:file_info, unquote_splicing(vals)}) do

lib/elixir/lib/float.ex

@@ -15,7 +15,7 @@ defmodule Float do
   ## Known issues
 
   There are some very well known problems with floating-point numbers
-  and arithmetic due to the fact most decimal fractions cannot be
+  and arithmetics due to the fact most decimal fractions cannot be
   represented by a floating-point binary and most operations are not exact,
   but operate on approximations. Those issues are not specific
   to Elixir, they are a property of floating point representation itself.
@@ -36,7 +36,7 @@ defmodule Float do
   To learn more about floating-point arithmetic visit:
 
     * [0.30000000000000004.com](http://0.30000000000000004.com/)
-    * [What Every Programmer Should Know About Floating-Point Arithmetic](https://floating-point-gui.de/)
+    * [What Every Programmer Should Know About Floating-Point Arithmetic](http://floating-point-gui.de/)
 
   """
 
@@ -46,71 +46,6 @@ defmodule Float do
   @precision_range 0..15
   @type precision_range :: 0..15
 
-  @min_finite then(<<0xFFEFFFFFFFFFFFFF::64>>, fn <<num::float>> -> num end)
-  @max_finite then(<<0x7FEFFFFFFFFFFFFF::64>>, fn <<num::float>> -> num end)
-
-  @doc """
-  Returns the maximum finite value for a float.
-
-  ## Examples
-
-      iex> Float.max_finite()
-      1.7976931348623157e308
-
-  """
-  def max_finite, do: @max_finite
-
-  @doc """
-  Returns the minimum finite value for a float.
-
-  ## Examples
-
-      iex> Float.min_finite()
-      -1.7976931348623157e308
-
-  """
-  def min_finite, do: @min_finite
-
-  @doc """
-  Computes `base` raised to power of `exponent`.
-
-  `base` must be a float and `exponent` can be any number.
-  However, if a negative base and a fractional exponent
-  are given, it raises `ArithmeticError`.
-
-  It always returns a float. See `Integer.pow/2` for
-  exponentiation that returns integers.
-
-  ## Examples
-
-      iex> Float.pow(2.0, 0)
-      1.0
-      iex> Float.pow(2.0, 1)
-      2.0
-      iex> Float.pow(2.0, 10)
-      1024.0
-      iex> Float.pow(2.0, -1)
-      0.5
-      iex> Float.pow(2.0, -3)
-      0.125
-
-      iex> Float.pow(3.0, 1.5)
-      5.196152422706632
-
-      iex> Float.pow(-2.0, 3)
-      -8.0
-      iex> Float.pow(-2.0, 4)
-      16.0
-
-      iex> Float.pow(-1.0, 0.5)
-      ** (ArithmeticError) bad argument in arithmetic expression
-
-  """
-  @doc since: "1.12.0"
-  @spec pow(float, number) :: float
-  def pow(base, exponent) when is_float(base) and is_number(exponent),
-    do: :math.pow(base, exponent)
-
   @doc """
   Parses a binary into a float.
 
@@ -119,8 +54,7 @@ defmodule Float do
   returned.
 
   If the size of float exceeds the maximum size of `1.7976931348623157e+308`,
-  `:error` is returned even though the textual representation itself might be
-  well formed.
+  the `ArgumentError` exception is raised.
 
   If you want to convert a string-formatted float directly to a float,
   `String.to_float/1` can be used instead.
@@ -136,8 +70,6 @@ defmodule Float do
 
       iex> Float.parse("pi")
       :error
-      iex> Float.parse("1.7976931348623159e+308")
-      :error
 
   """
   @spec parse(binary) :: {float, binary} | :error
@@ -175,18 +107,7 @@ defmodule Float do
        when exp_marker in 'eE' and sign in '-+' and digit in ?0..?9,
        do: parse_unsigned(rest, true, true, <<add_dot(acc, dot?)::binary, ?e, sign, digit>>)
 
-  # When floats are expressed in scientific notation, :erlang.binary_to_float/1 can raise an
-  # ArgumentError if the e exponent is too big. For example, "1.0e400". Because of this, we
-  # rescue the ArgumentError here and return an error.
-  defp parse_unsigned(rest, dot?, true = _e?, acc) do
-    :erlang.binary_to_float(add_dot(acc, dot?))
-  rescue
-    ArgumentError -> :error
-  else
-    float -> {float, rest}
-  end
-
-  defp parse_unsigned(rest, dot?, false = _e?, acc),
+  defp parse_unsigned(rest, dot?, _e?, acc),
     do: {:erlang.binary_to_float(add_dot(acc, dot?)), rest}
 
   defp add_dot(acc, true), do: acc
@@ -228,10 +149,6 @@ defmodule Float do
   @spec floor(float, precision_range) :: float
   def floor(number, precision \\ 0)
 
-  def floor(number, 0) when is_float(number) do
-    :math.floor(number)
-  end
-
   def floor(number, precision) when is_float(number) and precision in @precision_range do
     round(number, precision, :floor)
   end
@@ -275,10 +192,6 @@ defmodule Float do
   @spec ceil(float, precision_range) :: float
   def ceil(number, precision \\ 0)
 
-  def ceil(number, 0) when is_float(number) do
-    :math.ceil(number)
-  end
-
   def ceil(number, precision) when is_float(number) and precision in @precision_range do
     round(number, precision, :ceil)
   end
@@ -335,26 +248,25 @@ defmodule Float do
   # and could be implemented in the future.
   def round(float, precision \\ 0)
 
-  def round(float, 0) when is_float(float) do
-    float |> :erlang.round() |> :erlang.float()
-  end
-
   def round(float, precision) when is_float(float) and precision in @precision_range do
     round(float, precision, :half_up)
   end
 
-  def round(float, precision) when is_float(float) do
+  def round(number, precision) when is_float(number) do
     raise ArgumentError, invalid_precision_message(precision)
   end
 
-  defp round(0.0 = num, _precision, _rounding), do: num
-
   defp round(float, precision, rounding) do
     <<sign::1, exp::11, significant::52-bitstring>> = <<float::float>>
-    {num, count} = decompose(significant, 1)
+    {num, count, _} = decompose(significant)
     count = count - exp + 1023
 
     cond do
+      # There is no decimal precision
+      # zero or minus zero
+      count <= 0 or (0 == exp and <<0::52>> == significant) ->
+        float
+
       # Precision beyond 15 digits
       count >= 104 ->
         case rounding do
@@ -384,7 +296,7 @@ defmodule Float do
         num = rounding(rounding, sign, num, div)
 
         # Convert back to float without loss
-        # https://www.exploringbinary.com/correct-decimal-to-floating-point-using-big-integers/
+        # http://www.exploringbinary.com/correct-decimal-to-floating-point-using-big-integers/
         den = power_of_10(precision)
         boundary = den <<< 52
 
@@ -403,22 +315,6 @@ defmodule Float do
     end
   end
 
-  defp decompose(significant, initial) do
-    decompose(significant, 1, 0, initial)
-  end
-
-  defp decompose(<<1::1, bits::bitstring>>, count, last_count, acc) do
-    decompose(bits, count + 1, count, (acc <<< (count - last_count)) + 1)
-  end
-
-  defp decompose(<<0::1, bits::bitstring>>, count, last_count, acc) do
-    decompose(bits, count + 1, last_count, acc)
-  end
-
-  defp decompose(<<>>, _count, last_count, acc) do
-    {acc, last_count}
-  end
-
   defp scale_up(num, boundary, exp) when num >= boundary, do: {num, exp}
   defp scale_up(num, boundary, exp), do: scale_up(num <<< 1, boundary, exp - 1)
 
@@ -477,8 +373,6 @@ defmodule Float do
 
   ## Examples
 
-      iex> Float.ratio(0.0)
-      {0, 1}
       iex> Float.ratio(3.14)
       {7070651414971679, 2251799813685248}
       iex> Float.ratio(-3.14)
@@ -494,74 +388,59 @@ defmodule Float do
 
   """
   @doc since: "1.4.0"
-  @spec ratio(float) :: {integer, pos_integer}
-  def ratio(0.0), do: {0, 1}
-
+  @spec ratio(float) :: {pos_integer | neg_integer, pos_integer}
   def ratio(float) when is_float(float) do
-    <<sign::1, exp::11, mantissa::52>> = <<float::float>>
+    <<sign::1, exp::11, significant::52-bitstring>> = <<float::float>>
+    {num, _, den} = decompose(significant)
+    num = sign(sign, num)
 
-    {num, den_exp} =
-      if exp != 0 do
-        # Floats are expressed like this:
-        # (2**52 + mantissa) * 2**(-52 + exp - 1023)
-        #
-        # We compute the root factors of the mantissa so we have this:
-        # (2**52 + mantissa * 2**count) * 2**(-52 + exp - 1023)
-        {mantissa, count} = root_factors(mantissa, 0)
+    case exp - 1023 do
+      exp when exp > 0 ->
+        {den, exp} = shift_right(den, exp)
+        {shift_left(num, exp), den}
 
-        # Now we can move the count around so we have this:
-        # (2**(52-count) + mantissa) * 2**(count + -52 + exp - 1023)
-        if mantissa == 0 do
-          {1, exp - 1023}
-        else
-          num = (1 <<< (52 - count)) + mantissa
-          den_exp = count - 52 + exp - 1023
-          {num, den_exp}
-        end
-      else
-        # Subnormals are expressed like this:
-        # (mantissa) * 2**(-52 + 1 - 1023)
-        #
-        # So we compute it to this:
-        # (mantissa * 2**(count)) * 2**(-52 + 1 - 1023)
-        #
-        # Which becomes:
-        # mantissa * 2**(count-1074)
-        root_factors(mantissa, -1074)
-      end
+      exp when exp < 0 ->
+        {num, shift_left(den, -exp)}
 
-    if den_exp > 0 do
-      {sign(sign, num <<< den_exp), 1}
-    else
-      {sign(sign, num), 1 <<< -den_exp}
+      0 ->
+        {num, den}
     end
   end
 
-  defp root_factors(mantissa, count) when mantissa != 0 and (mantissa &&& 1) == 0,
-    do: root_factors(mantissa >>> 1, count + 1)
+  defp decompose(significant) do
+    decompose(significant, 1, 0, 2, 1, 1)
+  end
 
-  defp root_factors(mantissa, count),
-    do: {mantissa, count}
+  defp decompose(<<1::1, bits::bitstring>>, count, last_count, power, _last_power, acc) do
+    decompose(bits, count + 1, count, power <<< 1, power, shift_left(acc, count - last_count) + 1)
+  end
+
+  defp decompose(<<0::1, bits::bitstring>>, count, last_count, power, last_power, acc) do
+    decompose(bits, count + 1, last_count, power <<< 1, last_power, acc)
+  end
+
+  defp decompose(<<>>, _count, last_count, _power, last_power, acc) do
+    {acc, last_count, last_power}
+  end
 
-  @compile {:inline, sign: 2}
   defp sign(0, num), do: num
   defp sign(1, num), do: -num
 
+  defp shift_left(num, 0), do: num
+  defp shift_left(num, times), do: shift_left(num <<< 1, times - 1)
+
+  defp shift_right(num, 0), do: {num, 0}
+  defp shift_right(1, times), do: {1, times}
+  defp shift_right(num, times), do: shift_right(num >>> 1, times - 1)
+
   @doc """
-  Returns a charlist which corresponds to the shortest text representation
+  Returns a charlist which corresponds to the text representation
   of the given float.
 
-  The underlying algorithm changes depending on the Erlang/OTP version:
-
-    * For OTP >= 24, it uses the algorithm presented in "Ryū: fast
-      float-to-string conversion" in Proceedings of the SIGPLAN '2018
-      Conference on Programming Language Design and Implementation.
-
-    * For OTP < 24, it uses the algorithm presented in "Printing Floating-Point
-      Numbers Quickly and Accurately" in Proceedings of the SIGPLAN '1996
-      Conference on Programming Language Design and Implementation.
-
-  For a configurable representation, use `:erlang.float_to_list/2`.
+  It uses the shortest representation according to algorithm described
+  in "Printing Floating-Point Numbers Quickly and Accurately" in
+  Proceedings of the SIGPLAN '96 Conference on Programming Language
+  Design and Implementation.
 
   ## Examples
 
@@ -575,20 +454,13 @@ defmodule Float do
   end
 
   @doc """
-  Returns a binary which corresponds to the shortest text representation
+  Returns a binary which corresponds to the text representation
   of the given float.
 
-  The underlying algorithm changes depending on the Erlang/OTP version:
-
-    * For OTP >= 24, it uses the algorithm presented in "Ryū: fast
-      float-to-string conversion" in Proceedings of the SIGPLAN '2018
-      Conference on Programming Language Design and Implementation.
-
-    * For OTP < 24, it uses the algorithm presented in "Printing Floating-Point
-      Numbers Quickly and Accurately" in Proceedings of the SIGPLAN '1996
-      Conference on Programming Language Design and Implementation.
-
-  For a configurable representation, use `:erlang.float_to_binary/2`.
+  It uses the shortest representation according to algorithm described
+  in "Printing Floating-Point Numbers Quickly and Accurately" in
+  Proceedings of the SIGPLAN '96 Conference on Programming Language
+  Design and Implementation.
 
   ## Examples
 
@@ -602,16 +474,19 @@ defmodule Float do
   end
 
   @doc false
+  # TODO: Remove by 2.0
   @deprecated "Use Float.to_charlist/1 instead"
   def to_char_list(float), do: Float.to_charlist(float)
 
   @doc false
+  # TODO: Remove by 2.0
   @deprecated "Use :erlang.float_to_list/2 instead"
   def to_char_list(float, options) do
     :erlang.float_to_list(float, expand_compact(options))
   end
 
   @doc false
+  # TODO: Remove by 2.0
   @deprecated "Use :erlang.float_to_binary/2 instead"
   def to_string(float, options) do
     :erlang.float_to_binary(float, expand_compact(options))

lib/elixir/lib/function.ex

@@ -2,59 +2,11 @@ defmodule Function do
   @moduledoc """
   A set of functions for working with functions.
 
-  Anonymous functions are typically created by using `fn`:
-
-      iex> add = fn a, b -> a + b end
-      iex> add.(1, 2)
-      3
-
-  Anonymous functions can also have multiple clauses. All clauses
-  should expect the same number of arguments:
-
-      iex> negate = fn
-      ...>   true -> false
-      ...>   false -> true
-      ...> end
-      iex> negate.(false)
-      true
-
-  ## The capture operator
-
-  It is also possible to capture public module functions and pass them
-  around as if they were anonymous functions by using the capture
-  operator `&/1`:
-
-      iex> add = &Kernel.+/2
-      iex> add.(1, 2)
-      3
-
-      iex> length = &String.length/1
-      iex> length.("hello")
-      5
-
-  To capture a definition within the current module, you can skip the
-  module prefix, such as `&my_fun/2`. In those cases, the captured
-  function can be public (`def`) or private (`defp`).
-
-  The capture operator can also be used to create anonymous functions
-  that expect at least one argument:
-
-      iex> add = &(&1 + &2)
-      iex> add.(1, 2)
-      3
-
-  In such cases, using the capture operator is no different than using `fn`.
-
-  ## Internal and external functions
-
-  We say that functions that point to definitions residing in modules, such
-  as `&String.length/1`, are **external** functions. All other functions are
-  **local** and they are always bound to the file or module that defined them.
-
-  Besides the functions in this module to work with functions, `Kernel` also
-  has an `apply/2` function that invokes a function with a dynamic number of
-  arguments, as well as `is_function/1` and `is_function/2`, to check
-  respectively if a given value is a function or a function of a given arity.
+  There are two types of captured functions: **external** and **local**.
+  External functions are functions residing in modules that are captured
+  with `&/1`, such as `&String.length/1`. Local functions are anonymous functions
+  defined with `fn/1` or with the capture operator `&/1` using `&1`, `&2`,
+  and so on as replacements.
   """
 
   @type information ::
@@ -182,27 +134,4 @@ defmodule Function do
   @doc since: "1.7.0"
   @spec info(fun, item) :: {item, term} when item: information
   def info(fun, item), do: :erlang.fun_info(fun, item)
-
-  @doc """
-  Returns its input `value`. This function can be passed as an anonymous function
-  to transformation functions.
-
-  ## Examples
-
-      iex> Function.identity("Hello world!")
-      "Hello world!"
-
-      iex> 'abcdaabccc' |> Enum.sort() |> Enum.chunk_by(&Function.identity/1)
-      ['aaa', 'bb', 'cccc', 'd']
-
-      iex> Enum.group_by('abracadabra', &Function.identity/1)
-      %{97 => 'aaaaa', 98 => 'bb', 99 => 'c', 100 => 'd', 114 => 'rr'}
-
-      iex> Enum.map([1, 2, 3, 4], &Function.identity/1)
-      [1, 2, 3, 4]
-
-  """
-  @doc since: "1.10.0"
-  @spec identity(value) :: value when value: var
-  def identity(value), do: value
 end

lib/elixir/lib/gen_event.ex

@@ -1,13 +1,15 @@
 defmodule GenEvent do
+  # TODO: Remove by 2.0
+
   # Functions from this module are deprecated in elixir_dispatch.
 
   @moduledoc """
-  An event manager with event handlers behaviour.
+  A event manager with event handlers behaviour.
 
   If you are interested in implementing an event manager, please read the
   "Alternatives" section below. If you have to implement an event handler to
   integrate with an existing system, such as Elixir's Logger, please use
-  [`:gen_event`](`:gen_event`) instead.
+  `:gen_event` instead.
 
   ## Alternatives
 
@@ -38,7 +40,7 @@ defmodule GenEvent do
 
   If your use case requires exactly what GenEvent provided, or you have to
   integrate with an existing `:gen_event`-based system, you can still use the
-  [`:gen_event`](`:gen_event`) Erlang module.
+  [`:gen_event`](http://erlang.org/doc/man/gen_event.html) Erlang module.
   """
 
   @moduledoc deprecated: "Use Erlang/OTP's :gen_event module instead"
@@ -88,10 +90,12 @@ defmodule GenEvent do
   @deprecated message
   @doc false
   defmacro __using__(_) do
+    %{file: file, line: line} = __CALLER__
+
     deprecation_message =
       "the GenEvent module is deprecated, see its documentation for alternatives"
 
-    IO.warn(deprecation_message, __CALLER__)
+    :elixir_errors.warn(line, file, deprecation_message)
 
     quote location: :keep do
       @behaviour :gen_event
@@ -324,7 +328,14 @@ defmodule GenEvent do
 
   def init_it(starter, parent, name, _mod, _args, options) do
     Process.put(:"$initial_call", {__MODULE__, :init_it, 6})
-    debug = :gen.debug_options(name, options)
+
+    debug =
+      if function_exported?(:gen, :debug_options, 2) do
+        :gen.debug_options(name, options)
+      else
+        :gen.debug_options(options)
+      end
+
     :proc_lib.init_ack(starter, {:ok, self()})
     loop(parent, name(name), [], debug, false)
   end

lib/elixir/lib/gen_server.ex

@@ -16,7 +16,7 @@ defmodule GenServer do
 
   Let's start with a code example and then explore the available callbacks.
   Imagine we want a GenServer that works like a stack, allowing us to push
-  and pop elements:
+  and pop items:
 
       defmodule Stack do
         use GenServer
@@ -34,8 +34,8 @@ defmodule GenServer do
         end
 
         @impl true
-        def handle_cast({:push, element}, state) do
-          {:noreply, [element | state]}
+        def handle_cast({:push, item}, state) do
+          {:noreply, [item | state]}
         end
       end
 
@@ -54,16 +54,14 @@ defmodule GenServer do
 
   We start our `Stack` by calling `start_link/2`, passing the module
   with the server implementation and its initial argument (a list
-  representing the stack containing the element `:hello`). We can primarily
+  representing the stack containing the item `:hello`). We can primarily
   interact with the server by sending two types of messages. **call**
   messages expect a reply from the server (and are therefore synchronous)
   while **cast** messages do not.
 
   Every time you do a `GenServer.call/3`, the client will send a message
   that must be handled by the `c:handle_call/3` callback in the GenServer.
-  A `cast/2` message must be handled by `c:handle_cast/2`. There are 8 possible
-  callbacks to be implemented when you use a `GenServer`. The only required
-  callback is `c:init/1`.
+  A `cast/2` message must be handled by `c:handle_cast/2`.
 
   ## Client / Server APIs
 
@@ -83,8 +81,8 @@ defmodule GenServer do
           GenServer.start_link(__MODULE__, default)
         end
 
-        def push(pid, element) do
-          GenServer.cast(pid, {:push, element})
+        def push(pid, item) do
+          GenServer.cast(pid, {:push, item})
         end
 
         def pop(pid) do
@@ -104,8 +102,8 @@ defmodule GenServer do
         end
 
         @impl true
-        def handle_cast({:push, element}, state) do
-          {:noreply, [element | state]}
+        def handle_cast({:push, item}, state) do
+          {:noreply, [item | state]}
         end
       end
 
@@ -113,50 +111,25 @@ defmodule GenServer do
   the same module. If the server and/or client implementations are growing
   complex, you may want to have them in different modules.
 
-  ## How to supervise
+  ## use GenServer and callbacks
 
-  A `GenServer` is most commonly started under a supervision tree.
-  When we invoke `use GenServer`, it automatically defines a `child_spec/1`
-  function that allows us to start the `Stack` directly under a supervisor.
-  To start a default stack of `[:hello]` under a supervisor, one may do:
+  There are 7 callbacks to be implemented when you use a `GenServer`.
+  The only required callback is `init/1`.
 
-      children = [
-        {Stack, [:hello]}
-      ]
-
-      Supervisor.start_link(children, strategy: :one_for_all)
-
-  Note you can also start it simply as `Stack`, which is the same as
-  `{Stack, []}`:
-
-      children = [
-        Stack # The same as {Stack, []}
-      ]
-
-      Supervisor.start_link(children, strategy: :one_for_all)
-
-  In both cases, `Stack.start_link/1` is always invoked.
-
-  `use GenServer` also accepts a list of options which configures the
-  child specification and therefore how it runs under a supervisor.
-  The generated `child_spec/1` can be customized with the following options:
+  `use GenServer` also defines a `child_spec/1` function, allowing the
+  defined module to be put under a supervision tree. The generated
+  `child_spec/1` can be customized with the following options:
 
     * `:id` - the child specification identifier, defaults to the current module
+    * `:start` - how to start the child process (defaults to calling `__MODULE__.start_link/1`)
     * `:restart` - when the child should be restarted, defaults to `:permanent`
-    * `:shutdown` - how to shut down the child, either immediately or by giving it time to shut down
+    * `:shutdown` - how to shut down the child
 
   For example:
 
       use GenServer, restart: :transient, shutdown: 10_000
 
-  See the "Child specification" section in the `Supervisor` module for more
-  detailed information. The `@doc` annotation immediately preceding
-  `use GenServer` will be attached to the generated `child_spec/1` function.
-
-  When stopping the GenServer, for example by returning a `{:stop, reason, new_state}`
-  tuple from a callback, the exit reason is used by the supervisor to determine
-  whether the GenServer needs to be restarted. See the "Exit reasons and restarts"
-  section in the `Supervisor` module.
+  See the `Supervisor` docs for more information.
 
   ## Name registration
 
@@ -164,16 +137,16 @@ defmodule GenServer do
   a name on start via the `:name` option. Registered names are also
   automatically cleaned up on termination. The supported values are:
 
-    * an atom - the GenServer is registered locally (to the current node)
-      with the given name using `Process.register/2`.
+    * an atom - the GenServer is registered locally with the given name
+      using `Process.register/2`.
 
     * `{:global, term}` - the GenServer is registered globally with the given
-      term using the functions in the [`:global` module](`:global`).
+      term using the functions in the [`:global` module](http://www.erlang.org/doc/man/global.html).
 
     * `{:via, module, term}` - the GenServer is registered with the given
       mechanism and name. The `:via` option expects a module that exports
       `register_name/2`, `unregister_name/1`, `whereis_name/1` and `send/2`.
-      One such example is the [`:global` module](`:global`) which uses these functions
+      One such example is the [`:global` module](http://www.erlang.org/doc/man/global.html) which uses these functions
       for keeping the list of names of processes and their associated PIDs
       that are available globally for a network of Elixir nodes. Elixir also
       ships with a local, decentralized and scalable registry called `Registry`
@@ -185,8 +158,7 @@ defmodule GenServer do
       {:ok, _} = GenServer.start_link(Stack, [:hello], name: MyStack)
 
       # Now messages can be sent directly to MyStack
-      GenServer.call(MyStack, :pop)
-      #=> :hello
+      GenServer.call(MyStack, :pop) #=> :hello
 
   Once the server is started, the remaining functions in this module (`call/3`,
   `cast/2`, and friends) will also accept an atom, or any `{:global, ...}` or
@@ -212,7 +184,7 @@ defmodule GenServer do
   the GenServer callbacks as doing so will cause the GenServer to misbehave.
 
   Besides the synchronous and asynchronous communication provided by `call/3`
-  and `cast/2`, "regular" messages sent by functions such as `send/2`,
+  and `cast/2`, "regular" messages sent by functions such as `Kernel.send/2`,
   `Process.send_after/4` and similar, can be handled inside the `c:handle_info/2`
   callback.
 
@@ -223,57 +195,28 @@ defmodule GenServer do
       defmodule MyApp.Periodically do
         use GenServer
 
-        def start_link(_) do
+        def start_link do
           GenServer.start_link(__MODULE__, %{})
         end
 
         @impl true
         def init(state) do
-          # Schedule work to be performed on start
-          schedule_work()
-
+          schedule_work() # Schedule work to be performed on start
           {:ok, state}
         end
 
         @impl true
         def handle_info(:work, state) do
           # Do the desired work here
-          # ...
-
-          # Reschedule once more
-          schedule_work()
-
+          schedule_work() # Reschedule once more
           {:noreply, state}
         end
 
-        defp schedule_work do
-          # We schedule the work to happen in 2 hours (written in milliseconds).
-          # Alternatively, one might write :timer.hours(2)
-          Process.send_after(self(), :work, 2 * 60 * 60 * 1000)
+        defp schedule_work() do
+          Process.send_after(self(), :work, 2 * 60 * 60 * 1000) # In 2 hours
         end
       end
 
-  ## Timeouts
-
-  The return value of `c:init/1` or any of the `handle_*` callbacks may include
-  a timeout value in milliseconds; if not, `:infinity` is assumed.
-  The timeout can be used to detect a lull in incoming messages.
-
-  The `timeout()` value is used as follows:
-
-    * If the process has any message already waiting when the `timeout()` value
-      is returned, the timeout is ignored and the waiting message is handled as
-      usual. This means that even a timeout of `0` milliseconds is not guaranteed
-      to execute (if you want to take another action immediately and unconditionally,
-      use a `:continue` instruction instead).
-
-    * If any message arrives before the specified number of milliseconds
-      elapse, the timeout is cleared and that message is handled as usual.
-
-    * Otherwise, when the specified number of milliseconds have elapsed with no
-      message arriving, `handle_info/2` is called with `:timeout` as the first
-      argument.
-
   ## When (not) to use a GenServer
 
   So far, we have learned that a `GenServer` can be used as a supervised process
@@ -291,10 +234,6 @@ defmodule GenServer do
         GenServer.call(__MODULE__, {:add, a, b})
       end
 
-      def subtract(a, b) do
-        GenServer.call(__MODULE__, {:subtract, a, b})
-      end
-
       def handle_call({:add, a, b}, _from, state) do
         {:reply, a + b, state}
       end
@@ -322,14 +261,14 @@ defmodule GenServer do
 
   ## Debugging with the :sys module
 
-  GenServers, as [special processes](https://www.erlang.org/doc/design_principles/spec_proc.html),
-  can be debugged using the [`:sys` module](`:sys`).
+  GenServers, as [special processes](http://erlang.org/doc/design_principles/spec_proc.html),
+  can be debugged using the [`:sys` module](http://www.erlang.org/doc/man/sys.html).
   Through various hooks, this module allows developers to introspect the state of
   the process and trace system events that happen during its execution, such as
   received messages, sent replies and state changes.
 
   Let's explore the basic functions from the
-  [`:sys` module](`:sys`) used for debugging:
+  [`:sys` module](http://www.erlang.org/doc/man/sys.html) used for debugging:
 
     * `:sys.get_state/2` - allows retrieval of the state of the process.
       In the case of a GenServer process, it will be the callback module state,
@@ -361,48 +300,29 @@ defmodule GenServer do
       *DBG* <0.122.0> got cast {push,1}
       *DBG* <0.122.0> new state [1]
       :ok
-
       iex> :sys.get_state(pid)
       [1]
-
       iex> Stack.pop(pid)
       *DBG* <0.122.0> got call pop from <0.80.0>
       *DBG* <0.122.0> sent 1 to <0.80.0>, new state []
       1
-
       iex> :sys.statistics(pid, :get)
       {:ok,
-       [
-         start_time: {{2016, 7, 16}, {12, 29, 41}},
-         current_time: {{2016, 7, 16}, {12, 29, 50}},
-         reductions: 117,
-         messages_in: 2,
-         messages_out: 0
-       ]}
-
+       [start_time: {{2016, 7, 16}, {12, 29, 41}},
+        current_time: {{2016, 7, 16}, {12, 29, 50}},
+        reductions: 117, messages_in: 2, messages_out: 0]}
       iex> :sys.no_debug(pid) # turn off all debug handlers
       :ok
-
       iex> :sys.get_status(pid)
       {:status, #PID<0.122.0>, {:module, :gen_server},
-       [
-         [
-           "$initial_call": {Stack, :init, 1},            # process dictionary
-           "$ancestors": [#PID<0.80.0>, #PID<0.51.0>]
-         ],
-         :running,                                        # :running | :suspended
-         #PID<0.80.0>,                                    # parent
-         [],                                              # debugger state
-         [
-           header: 'Status for generic server <0.122.0>', # module status
-           data: [
-             {'Status', :running},
-             {'Parent', #PID<0.80.0>},
-             {'Logged events', []}
-           ],
-           data: [{'State', [1]}]
-         ]
-       ]}
+       [["$initial_call": {Stack, :init, 1},            # pdict
+         "$ancestors": [#PID<0.80.0>, #PID<0.51.0>]],
+        :running,                                       # :running | :suspended
+        #PID<0.80.0>,                                   # parent
+        [],                                             # debugger state
+        [header: 'Status for generic server <0.122.0>', # module status
+         data: [{'Status', :running}, {'Parent', #PID<0.80.0>},
+           {'Logged events', []}], data: [{'State', [1]}]]]}
 
   ## Learn more
 
@@ -410,10 +330,10 @@ defmodule GenServer do
   guide provides a tutorial-like introduction. The documentation and links
   in Erlang can also provide extra insight.
 
-    * [GenServer - Elixir's Getting Started Guide](https://elixir-lang.org/getting-started/mix-otp/genserver.html)
-    * [`:gen_server` module documentation](`:gen_server`)
-    * [gen_server Behaviour - OTP Design Principles](https://www.erlang.org/doc/design_principles/gen_server_concepts.html)
-    * [Clients and Servers - Learn You Some Erlang for Great Good!](http://learnyousomeerlang.com/clients-and-servers)
+    * [GenServer – Elixir's Getting Started Guide](http://elixir-lang.org/getting-started/mix-otp/genserver.html)
+    * [`:gen_server` module documentation](http://www.erlang.org/doc/man/gen_server.html)
+    * [gen_server Behaviour – OTP Design Principles](http://www.erlang.org/doc/design_principles/gen_server_concepts.html)
+    * [Clients and Servers – Learn You Some Erlang for Great Good!](http://learnyousomeerlang.com/clients-and-servers)
 
   """
 
@@ -421,23 +341,23 @@ defmodule GenServer do
   Invoked when the server is started. `start_link/3` or `start/3` will
   block until it returns.
 
-  `init_arg` is the argument term (second argument) passed to `start_link/3`.
+  `args` is the argument term (second argument) passed to `start_link/3`.
 
   Returning `{:ok, state}` will cause `start_link/3` to return
   `{:ok, pid}` and the process to enter its loop.
 
-  Returning `{:ok, state, timeout}` is similar to `{:ok, state}`,
-  except that it also sets a timeout. See the "Timeouts" section
-  in the module documentation for more information.
+  Returning `{:ok, state, timeout}` is similar to `{:ok, state}`
+  except `handle_info(:timeout, state)` will be called after `timeout`
+  milliseconds if no messages are received within the timeout.
 
   Returning `{:ok, state, :hibernate}` is similar to `{:ok, state}`
   except the process is hibernated before entering the loop. See
   `c:handle_call/3` for more information on hibernation.
 
-  Returning `{:ok, state, {:continue, continue_arg}}` is similar to
-  `{:ok, state}` except that immediately after entering the loop,
-  the `c:handle_continue/2` callback will be invoked with `continue_arg`
-  as the first argument and `state` as the second one.
+  Returning `{:ok, state, {:continue, continue}}` is similar to
+  `{:ok, state}` except that immediately after entering the loop
+  the `c:handle_continue/2` callback will be invoked with the value
+  `continue` as first argument.
 
   Returning `:ignore` will cause `start_link/3` to return `:ignore` and
   the process will exit normally without entering the loop or calling
@@ -458,9 +378,9 @@ defmodule GenServer do
   `{:error, reason}` and the process to exit with reason `reason` without
   entering the loop or calling `c:terminate/2`.
   """
-  @callback init(init_arg :: term) ::
+  @callback init(args :: term) ::
               {:ok, state}
-              | {:ok, state, timeout | :hibernate | {:continue, continue_arg :: term}}
+              | {:ok, state, timeout | :hibernate | {:continue, term}}
               | :ignore
               | {:stop, reason :: any}
             when state: any
@@ -477,20 +397,19 @@ defmodule GenServer do
   caller and continues the loop with new state `new_state`.
 
   Returning `{:reply, reply, new_state, timeout}` is similar to
-  `{:reply, reply, new_state}` except that it also sets a timeout.
-  See the "Timeouts" section in the module documentation for more information.
+  `{:reply, reply, new_state}` except `handle_info(:timeout, new_state)` will be
+  called after `timeout` milliseconds if no messages are received.
 
   Returning `{:reply, reply, new_state, :hibernate}` is similar to
   `{:reply, reply, new_state}` except the process is hibernated and will
-  continue the loop once a message is in its message queue. However, if a message is
-  already in the message queue, the process will continue the loop immediately. Hibernating a
+  continue the loop once a message is in its message queue. If a message is
+  already in the message queue this will be immediately. Hibernating a
   `GenServer` causes garbage collection and leaves a continuous heap that
   minimises the memory used by the process.
 
-  Returning `{:reply, reply, new_state, {:continue, continue_arg}}` is similar to
-  `{:reply, reply, new_state}` except that `c:handle_continue/2` will be invoked
-  immediately after with `continue_arg` as the first argument and
-  `state` as the second one.
+  Returning `{:reply, reply, new_state, {:continue, continue}}` is similar to
+  `{:reply, reply, new_state}` except `c:handle_continue/2` will be invoked
+  immediately after with the value `continue` as first argument.
 
   Hibernating should not be used aggressively as too much time could be spent
   garbage collecting. Normally it should only be used when a message is not
@@ -513,12 +432,12 @@ defmodule GenServer do
   process exits without replying as the caller will be blocking awaiting a
   reply.
 
-  Returning `{:noreply, new_state, timeout | :hibernate | {:continue, continue_arg}}`
+  Returning `{:noreply, new_state, timeout | :hibernate | {:continue, continue}}`
   is similar to `{:noreply, new_state}` except a timeout, hibernation or continue
   occurs as with a `:reply` tuple.
 
   Returning `{:stop, reason, reply, new_state}` stops the loop and `c:terminate/2`
-  is called with reason `reason` and state `new_state`. Then, the `reply` is sent
+  is called with reason `reason` and state `new_state`. Then the `reply` is sent
   as the response to call and the process exits with reason `reason`.
 
   Returning `{:stop, reason, new_state}` is similar to
@@ -529,10 +448,9 @@ defmodule GenServer do
   """
   @callback handle_call(request :: term, from, state :: term) ::
               {:reply, reply, new_state}
-              | {:reply, reply, new_state,
-                 timeout | :hibernate | {:continue, continue_arg :: term}}
+              | {:reply, reply, new_state, timeout | :hibernate | {:continue, term}}
               | {:noreply, new_state}
-              | {:noreply, new_state, timeout | :hibernate | {:continue, continue_arg :: term}}
+              | {:noreply, new_state, timeout | :hibernate, {:continue, term}}
               | {:stop, reason, reply, new_state}
               | {:stop, reason, new_state}
             when reply: term, new_state: term, reason: term
@@ -545,18 +463,17 @@ defmodule GenServer do
 
   Returning `{:noreply, new_state}` continues the loop with new state `new_state`.
 
-  Returning `{:noreply, new_state, timeout}` is similar to `{:noreply, new_state}`
-  except that it also sets a timeout. See the "Timeouts" section in the module
-  documentation for more information.
+  Returning `{:noreply, new_state, timeout}` is similar to
+  `{:noreply, new_state}` except `handle_info(:timeout, new_state)` will be
+  called after `timeout` milliseconds if no messages are received.
 
   Returning `{:noreply, new_state, :hibernate}` is similar to
   `{:noreply, new_state}` except the process is hibernated before continuing the
   loop. See `c:handle_call/3` for more information.
 
-  Returning `{:noreply, new_state, {:continue, continue_arg}}` is similar to
+  Returning `{:noreply, new_state, {:continue, continue}}` is similar to
   `{:noreply, new_state}` except `c:handle_continue/2` will be invoked
-  immediately after with `continue_arg` as the first argument and
-  `state` as the second one.
+  immediately after with the value `continue` as first argument.
 
   Returning `{:stop, reason, new_state}` stops the loop and `c:terminate/2` is
   called with the reason `reason` and state `new_state`. The process exits with
@@ -567,7 +484,7 @@ defmodule GenServer do
   """
   @callback handle_cast(request :: term, state :: term) ::
               {:noreply, new_state}
-              | {:noreply, new_state, timeout | :hibernate | {:continue, continue_arg :: term}}
+              | {:noreply, new_state, timeout | :hibernate | {:continue, term}}
               | {:stop, reason :: term, new_state}
             when new_state: term
 
@@ -584,12 +501,12 @@ defmodule GenServer do
   """
   @callback handle_info(msg :: :timeout | term, state :: term) ::
               {:noreply, new_state}
-              | {:noreply, new_state, timeout | :hibernate | {:continue, continue_arg :: term}}
+              | {:noreply, new_state, timeout | :hibernate | {:continue, term}}
               | {:stop, reason :: term, new_state}
             when new_state: term
 
   @doc """
-  Invoked to handle continue instructions.
+  Invoked to handle `continue` instructions.
 
   It is useful for performing work after initialization or for splitting the work
   in a callback in multiple steps, updating the process state along the way.
@@ -598,12 +515,14 @@ defmodule GenServer do
 
   This callback is optional. If one is not implemented, the server will fail
   if a continue instruction is used.
+
+  This callback is only supported on Erlang/OTP 21+.
   """
-  @callback handle_continue(continue_arg, state :: term) ::
+  @callback handle_continue(continue :: term, state :: term) ::
               {:noreply, new_state}
-              | {:noreply, new_state, timeout | :hibernate | {:continue, continue_arg}}
+              | {:noreply, new_state, timeout | :hibernate | {:continue, term}}
               | {:stop, reason :: term, new_state}
-            when new_state: term, continue_arg: term
+            when new_state: term
 
   @doc """
   Invoked when the server is about to exit. It should do any cleanup required.
@@ -611,28 +530,23 @@ defmodule GenServer do
   `reason` is exit reason and `state` is the current state of the `GenServer`.
   The return value is ignored.
 
-  `c:terminate/2` is called if the `GenServer` traps exits (using `Process.flag/2`)
-  *and* the parent process sends an exit signal, or a callback (except `c:init/1`)
-  does one of the following:
+  `c:terminate/2` is called if a callback (except `c:init/1`) does one of the
+  following:
 
     * returns a `:stop` tuple
-    * raises (via `raise/2`) or exits (via `exit/1`)
+    * raises
+    * calls `Kernel.exit/1`
     * returns an invalid value
+    * the `GenServer` traps exits (using `Process.flag/2`) *and* the parent
+      process sends an exit signal
 
-  If part of a supervision tree, a `GenServer` will receive an exit
-  signal when the tree is shutting down. The exit signal is based on
-  the shutdown strategy in the child's specification, where this
-  value can be:
-
-    * `:brutal_kill`: the `GenServer` is killed and so `c:terminate/2` is not called.
-
-    * a timeout value, where the supervisor will send the exit signal `:shutdown` and
-      the `GenServer` will have the duration of the timeout to terminate.
-      If after duration of this timeout the process is still alive, it will be killed
-      immediately.
-
-  For a more in-depth explanation, please read the "Shutdown values (:shutdown)"
-  section in the `Supervisor` module.
+  If part of a supervision tree, a `GenServer`'s `Supervisor` will send an exit
+  signal when shutting it down. The exit signal is based on the shutdown
+  strategy in the child's specification. If it is `:brutal_kill` the `GenServer`
+  is killed and so `c:terminate/2` is not called. However if it is a timeout the
+  `Supervisor` will send the exit signal `:shutdown` and the `GenServer` will
+  have the duration of the timeout to call `c:terminate/2` - if the process is
+  still alive after the timeout it is killed.
 
   If the `GenServer` receives an exit signal (that is not `:normal`) from any
   process when it is not trapping exits it will exit abruptly with the same
@@ -643,18 +557,18 @@ defmodule GenServer do
   Therefore it is not guaranteed that `c:terminate/2` is called when a `GenServer`
   exits. For such reasons, we usually recommend important clean-up rules to
   happen in separated processes either by use of monitoring or by links
-  themselves. There is no cleanup needed when the `GenServer` controls a `port` (for example,
+  themselves. There is no cleanup needed when the `GenServer` controls a `port` (e.g.
   `:gen_tcp.socket`) or `t:File.io_device/0`, because these will be closed on
   receiving a `GenServer`'s exit signal and do not need to be closed manually
   in `c:terminate/2`.
 
-  If `reason` is neither `:normal`, `:shutdown`, nor `{:shutdown, term}` an error is
+  If `reason` is not `:normal`, `:shutdown`, nor `{:shutdown, term}` an error is
   logged.
 
   This callback is optional.
   """
   @callback terminate(reason, state :: term) :: term
-            when reason: :normal | :shutdown | {:shutdown, term} | term
+            when reason: :normal | :shutdown | {:shutdown, term}
 
   @doc """
   Invoked to change the state of the `GenServer` when a different version of a
@@ -680,10 +594,15 @@ defmodule GenServer do
   @callback code_change(old_vsn, state :: term, extra :: term) ::
               {:ok, new_state :: term}
               | {:error, reason :: term}
-            when old_vsn: term | {:down, term}
+              | {:down, term}
+            when old_vsn: term
 
   @doc """
-  Invoked in some cases to retrieve a formatted version of the `GenServer` status:
+  Invoked in some cases to retrieve a formatted version of the `GenServer` status.
+
+  This callback can be useful to control the *appearance* of the status of the
+  `GenServer`. For example, it can be used to return a compact representation of
+  the `GenServer`'s state to avoid having large state terms printed.
 
     * one of `:sys.get_status/1` or `:sys.get_status/2` is invoked to get the
       status of the `GenServer`; in such cases, `reason` is `:normal`
@@ -691,10 +610,6 @@ defmodule GenServer do
     * the `GenServer` terminates abnormally and logs an error; in such cases,
       `reason` is `:terminate`
 
-  This callback can be useful to control the *appearance* of the status of the
-  `GenServer`. For example, it can be used to return a compact representation of
-  the `GenServer`'s state to avoid having large state terms printed.
-
   `pdict_and_state` is a two-elements list `[pdict, state]` where `pdict` is a
   list of `{key, value}` tuples representing the current process dictionary of
   the `GenServer` and `state` is the current state of the `GenServer`.
@@ -724,18 +639,12 @@ defmodule GenServer do
           {:debug, debug}
           | {:name, name}
           | {:timeout, timeout}
-          | {:spawn_opt, [Process.spawn_opt()]}
-          | {:hibernate_after, timeout}
+          | {:spawn_opt, Process.spawn_opt()}
 
   @typedoc "Debug options supported by the `start*` functions"
   @type debug :: [:trace | :log | :statistics | {:log_to_file, Path.t()}]
 
-  @typedoc """
-  The server reference.
-
-  This is either a plain PID or a value representing a registered name.
-  See the "Name registration" section of this document for more information.
-  """
+  @typedoc "The server reference"
   @type server :: pid | name | {atom, node}
 
   @typedoc """
@@ -751,18 +660,15 @@ defmodule GenServer do
     quote location: :keep, bind_quoted: [opts: opts] do
       @behaviour GenServer
 
-      unless Module.has_attribute?(__MODULE__, :doc) do
-        @doc """
-        Returns a specification to start this module under a supervisor.
+      @doc """
+      Returns a specification to start this module under a supervisor.
 
-        See `Supervisor`.
-        """
-      end
-
-      def child_spec(init_arg) do
+      See `Supervisor`.
+      """
+      def child_spec(arg) do
         default = %{
           id: __MODULE__,
-          start: {__MODULE__, :start_link, [init_arg]}
+          start: {__MODULE__, :start_link, [arg]}
         }
 
         Supervisor.child_spec(default, unquote(Macro.escape(opts)))
@@ -770,7 +676,7 @@ defmodule GenServer do
 
       defoverridable child_spec: 1
 
-      # TODO: Remove this on v2.0
+      # TODO: Remove this on Elixir v2.0
       @before_compile GenServer
 
       @doc false
@@ -799,22 +705,8 @@ defmodule GenServer do
             {_, name} -> name
           end
 
-        :logger.error(
-          %{
-            label: {GenServer, :no_handle_info},
-            report: %{
-              module: __MODULE__,
-              message: msg,
-              name: proc
-            }
-          },
-          %{
-            domain: [:otp, :elixir],
-            error_logger: %{tag: :error_msg},
-            report_cb: &GenServer.format_report/1
-          }
-        )
-
+        pattern = '~p ~p received unexpected message in handle_info/2: ~p~n'
+        :error_logger.error_msg(pattern, [__MODULE__, proc, msg])
         {:noreply, state}
       end
 
@@ -858,20 +750,20 @@ defmodule GenServer do
 
       We will inject a default implementation for now:
 
-          def init(init_arg) do
-            {:ok, init_arg}
+          def init(args) do
+            {:ok, args}
           end
 
       You can copy the implementation above or define your own that converts \
       the arguments given to GenServer.start_link/3 to the server state.
       """
 
-      IO.warn(message, env)
+      :elixir_errors.warn(env.line, env.file, message)
 
       quote do
         @doc false
-        def init(init_arg) do
-          {:ok, init_arg}
+        def init(args) do
+          {:ok, args}
         end
 
         defoverridable init: 1
@@ -885,7 +777,7 @@ defmodule GenServer do
   This is often used to start the `GenServer` as part of a supervision tree.
 
   Once the server is started, the `c:init/1` function of the given `module` is
-  called with `init_arg` as its argument to initialize the server. To ensure a
+  called with `args` as its arguments to initialize the server. To ensure a
   synchronized start-up procedure, this function does not return until `c:init/1`
   has returned.
 
@@ -903,15 +795,11 @@ defmodule GenServer do
       milliseconds initializing or it will be terminated and the start function
       will return `{:error, :timeout}`
 
-    * `:debug` - if present, the corresponding function in the [`:sys` module](`:sys`) is invoked
+    * `:debug` - if present, the corresponding function in the [`:sys` module](http://www.erlang.org/doc/man/sys.html) is invoked
 
     * `:spawn_opt` - if present, its value is passed as options to the
       underlying process as in `Process.spawn/4`
 
-    * `:hibernate_after` - if present, the GenServer process awaits any message for
-      the given number of milliseconds and if no message is received, the process goes
-      into hibernation automatically (by calling `:proc_lib.hibernate/3`).
-
   ## Return values
 
   If the server is successfully created and initialized, this function returns
@@ -925,8 +813,8 @@ defmodule GenServer do
   `{:error, reason}` or `:ignore`, respectively.
   """
   @spec start_link(module, any, options) :: on_start
-  def start_link(module, init_arg, options \\ []) when is_atom(module) and is_list(options) do
-    do_start(:link, module, init_arg, options)
+  def start_link(module, args, options \\ []) when is_atom(module) and is_list(options) do
+    do_start(:link, module, args, options)
   end
 
   @doc """
@@ -935,23 +823,23 @@ defmodule GenServer do
   See `start_link/3` for more information.
   """
   @spec start(module, any, options) :: on_start
-  def start(module, init_arg, options \\ []) when is_atom(module) and is_list(options) do
-    do_start(:nolink, module, init_arg, options)
+  def start(module, args, options \\ []) when is_atom(module) and is_list(options) do
+    do_start(:nolink, module, args, options)
   end
 
-  defp do_start(link, module, init_arg, options) do
+  defp do_start(link, module, args, options) do
     case Keyword.pop(options, :name) do
       {nil, opts} ->
-        :gen.start(:gen_server, link, module, init_arg, opts)
+        :gen.start(:gen_server, link, module, args, opts)
 
       {atom, opts} when is_atom(atom) ->
-        :gen.start(:gen_server, link, {:local, atom}, module, init_arg, opts)
+        :gen.start(:gen_server, link, {:local, atom}, module, args, opts)
 
       {{:global, _term} = tuple, opts} ->
-        :gen.start(:gen_server, link, tuple, module, init_arg, opts)
+        :gen.start(:gen_server, link, tuple, module, args, opts)
 
       {{:via, via_module, _term} = tuple, opts} when is_atom(via_module) ->
-        :gen.start(:gen_server, link, tuple, module, init_arg, opts)
+        :gen.start(:gen_server, link, tuple, module, args, opts)
 
       {other, _} ->
         raise ArgumentError, """
@@ -1020,13 +908,11 @@ defmodule GenServer do
   element.
   """
   @spec call(server, term, timeout) :: term
-  def call(server, request, timeout \\ 5000)
-      when (is_integer(timeout) and timeout >= 0) or timeout == :infinity do
+  def call(server, request, timeout \\ 5000) do
     case whereis(server) do
       nil ->
         exit({:noproc, {__MODULE__, :call, [server, request, timeout]}})
 
-      # TODO: remove this clause when we require Erlang/OTP 25+
       pid when pid == self() ->
         exit({:calling_self, {__MODULE__, :call, [server, request, timeout]}})
 
@@ -1050,8 +936,13 @@ defmodule GenServer do
   is unknown whether the destination `server` successfully
   handled the message.
 
-  `server` can be any of the values described in the "Name registration"
-  section of the documentation for this module.
+  `c:handle_cast/2` will be called on the server to handle
+  the request. In case the `server` is on a node which is
+  not yet connected to the caller one, the call is going to
+  block until a connection happens. This is different than
+  the behaviour in OTP's `:gen_server` where the message
+  is sent by another process in this case, which could cause
+  messages to other nodes to arrive out of order.
   """
   @spec cast(server, term) :: :ok
   def cast(server, request)
@@ -1174,16 +1065,20 @@ defmodule GenServer do
 
   """
   @spec reply(from, term) :: :ok
-  def reply(client, reply) do
-    :gen.reply(client, reply)
+  def reply(client, reply)
+
+  def reply({to, tag}, reply) when is_pid(to) do
+    try do
+      send(to, {tag, reply})
+      :ok
+    catch
+      _, _ -> :ok
+    end
   end
 
   @doc """
-  Returns the `pid` or `{name, node}` of a GenServer process, `nil` otherwise.
-
-  To be precise, `nil` is returned whenever a `pid` or `{name, node}` cannot
-  be returned. Note there is no guarantee the returned `pid` or `{name, node}`
-  is alive, as a process could terminate immediately after it is looked up.
+  Returns the `pid` or `{name, node}` of a GenServer process, or `nil` if
+  no process is associated with the given `server`.
 
   ## Examples
 
@@ -1224,12 +1119,4 @@ defmodule GenServer do
   def whereis({name, node} = server) when is_atom(name) and is_atom(node) do
     server
   end
-
-  @doc false
-  def format_report(%{
-        label: {GenServer, :no_handle_info},
-        report: %{module: mod, message: msg, name: proc}
-      }) do
-    {'~p ~p received unexpected message in handle_info/2: ~p~n', [mod, proc, msg]}
-  end
 end

lib/elixir/lib/hash_dict.ex

@@ -7,6 +7,8 @@ defmodule HashDict do
 
   @moduledoc deprecated: "Use Map instead"
 
+  # TODO: Remove by 2.0
+
   use Dict
 
   @node_bitmap 0b111
@@ -48,8 +50,8 @@ defmodule HashDict do
   end
 
   @deprecated message
-  def update(%HashDict{root: root, size: size}, key, default, fun) when is_function(fun, 1) do
-    {root, counter} = do_update(root, key, fn -> default end, fun, key_hash(key))
+  def update(%HashDict{root: root, size: size}, key, initial, fun) when is_function(fun, 1) do
+    {root, counter} = do_update(root, key, fn -> initial end, fun, key_hash(key))
     %HashDict{root: root, size: size + counter}
   end
 
@@ -135,25 +137,25 @@ defmodule HashDict do
     end
   end
 
-  defp do_update(node, key, default, fun, hash) do
+  defp do_update(node, key, initial, fun, hash) do
     index = key_mask(hash)
 
     case elem(node, index) do
       [] ->
-        {put_elem(node, index, [key | default.()]), 1}
+        {put_elem(node, index, [key | initial.()]), 1}
 
       [^key | value] ->
         {put_elem(node, index, [key | fun.(value)]), 0}
 
       [k | v] ->
-        n = put_elem(@node_template, key_mask(key_shift(hash)), [key | default.()])
+        n = put_elem(@node_template, key_mask(key_shift(hash)), [key | initial.()])
         {put_elem(node, index, {k, v, n}), 1}
 
       {^key, value, n} ->
         {put_elem(node, index, {key, fun.(value), n}), 0}
 
       {k, v, n} ->
-        {n, counter} = do_update(n, key, default, fun, key_shift(hash))
+        {n, counter} = do_update(n, key, initial, fun, key_shift(hash))
         {put_elem(node, index, {k, v, n}), counter}
     end
   end

lib/elixir/lib/inspect.ex

@@ -8,119 +8,48 @@ defprotocol Inspect do
   The `Inspect` protocol converts an Elixir data structure into an
   algebra document.
 
-  This is typically done when you want to customize how your own
-  structs are inspected in logs and the terminal.
-
   This documentation refers to implementing the `Inspect` protocol
   for your own data structures. To learn more about using inspect,
   see `Kernel.inspect/2` and `IO.inspect/2`.
 
-  ## Inspect representation
+  The `inspect/2` function receives the entity to be inspected
+  followed by the inspecting options, represented by the struct
+  `Inspect.Opts`. Building of the algebra document is done with
+  `Inspect.Algebra`.
 
-  There are typically three choices of inspect representation. In order
-  to understand them, let's imagine we have the following `User` struct:
-
-      defmodule User do
-        defstruct [:id, :name, :address]
-      end
-
-  Our choices are:
-
-    1. Print the struct using Elixir's struct syntax, for example:
-       `%User{address: "Earth", id: 13, name: "Jane"}`. This is the
-       default representation and best choice if all struct fields
-       are public.
-
-    2. Print using the `#User<...>` notation, for example: `#User<id: 13, name: "Jane", ...>`.
-       This notation does not emit valid Elixir code and is typically
-       used when the struct has private fields (for example, you may want
-       to hide the field `:address` to redact person identifiable information).
-
-    3. Print the struct using the expression syntax, for example:
-       `User.new(13, "Jane", "Earth")`. This assumes there is a `User.new/3`
-       function. This option is mostly used as an alternative to option 2
-       for representing custom data structures, such as `MapSet`, `Date.Range`,
-       and others.
-
-  You can implement the Inspect protocol for your own structs while
-  adhering to the conventions above. Option 1 is the default representation
-  and you can quickly achieve option 2 by deriving the `Inspect` protocol.
-  For option 3, you need your custom implementation.
-
-  ## Deriving
-
-  The `Inspect` protocol can be derived to customize the order of fields
-  (the default is alphabetical) and hide certain fields from structs,
-  so they don't show up in logs, inspects and similar. The latter is
-  especially useful for fields containing private information.
-
-  The supported options are:
-
-    * `:only` - only include the given fields when inspecting.
-
-    * `:except` - remove the given fields when inspecting.
-
-    * `:optional` - (since v1.14.0) do not include a field if it
-      matches its default value. This can be used to simplify the
-      struct representation at the cost of hiding information.
-
-  Whenever `:only` or `:except` are used to restrict fields,
-  the struct will be printed using the `#User<...>` notation,
-  as the struct can no longer be copy and pasted as valid Elixir
-  code. Let's see an example:
-
-      defmodule User do
-        @derive {Inspect, only: [:id, :name]}
-        defstruct [:id, :name, :address]
-      end
-
-      inspect(%User{id: 1, name: "Jane", address: "Earth"})
-      #=> #User<id: 1, name: "Jane", ...>
-
-  If you use only the `:optional` option, the struct will still be
-  printed as `%User{...}`.
-
-  ## Custom implementation
-
-  You can also define your custom protocol implementation by
-  defining the `inspect/2` function. The function receives the
-  entity to be inspected followed by the inspecting options,
-  represented by the struct `Inspect.Opts`. Building of the
-  algebra document is done with `Inspect.Algebra`.
+  ## Examples
 
   Many times, inspecting a structure can be implemented in function
-  of existing entities. For example, here is `MapSet`'s `inspect/2`
+  of existing entities. For example, here is `MapSet`'s `inspect`
   implementation:
 
       defimpl Inspect, for: MapSet do
         import Inspect.Algebra
 
-        def inspect(map_set, opts) do
-          concat(["MapSet.new(", Inspect.List.inspect(MapSet.to_list(map_set), opts), ")"])
+        def inspect(dict, opts) do
+          concat(["#MapSet<", to_doc(MapSet.to_list(dict), opts), ">"])
         end
       end
 
-  The [`concat/1`](`Inspect.Algebra.concat/1`) function comes from
-  `Inspect.Algebra` and it concatenates algebra documents together.
-  In the example above it is concatenating the string `"MapSet.new("`,
-  the document returned by `Inspect.Algebra.to_doc/2`, and the final
-  string `")"`. Therefore, the MapSet with the numbers 1, 2, and 3
-  will be printed as:
+  The `concat/1` function comes from `Inspect.Algebra` and it
+  concatenates algebra documents together. In the example above,
+  it is concatenating the string `"MapSet<"` (all strings are
+  valid algebra documents that keep their formatting when pretty
+  printed), the document returned by `Inspect.Algebra.to_doc/2` and the
+  other string `">"`.
 
-      iex> MapSet.new([1, 2, 3], fn x -> x * 2 end)
-      MapSet.new([2, 4, 6])
+  Since regular strings are valid entities in an algebra document,
+  an implementation of inspect may simply return a string,
+  although that will devoid it of any pretty-printing.
 
-  In other words, `MapSet`'s inspect representation returns an expression
-  that, when evaluated, builds the `MapSet` itself.
-
-  ### Error handling
+  ## Error handling
 
   In case there is an error while your structure is being inspected,
   Elixir will raise an `ArgumentError` error and will automatically fall back
   to a raw representation for printing the structure.
 
-  You can however access the underlying error by invoking the `Inspect`
-  implementation directly. For example, to test `Inspect.MapSet` above,
+  You can however access the underlying error by invoking the Inspect
+  implementation directly. For example, to test Inspect.MapSet above,
   you can invoke it as:
 
       Inspect.MapSet.inspect(MapSet.new(), %Inspect.Opts{})
@@ -130,15 +59,6 @@ defprotocol Inspect do
   # Handle structs in Any
   @fallback_to_any true
 
-  @doc """
-  Converts `term` into an algebra document.
-
-  This function shouldn't be invoked directly, unless when implementing
-  a custom `inspect_fun` to be given to `Inspect.Opts`. Everywhere else,
-  `Inspect.Algebra.to_doc/2` should be preferred as it handles structs
-  and exceptions.
-  """
-  @spec inspect(t, Inspect.Opts.t()) :: Inspect.Algebra.t()
   def inspect(term, opts)
 end
 
@@ -146,7 +66,7 @@ defimpl Inspect, for: Atom do
   require Macro
 
   def inspect(atom, opts) do
-    color(Macro.inspect_atom(:literal, atom), color_key(atom), opts)
+    color(Identifier.inspect_as_atom(atom), color_key(atom), opts)
   end
 
   defp color_key(atom) when is_boolean(atom), do: :boolean
@@ -209,7 +129,7 @@ defimpl Inspect, for: BitString do
   defp each_bit(bitstring, _counter, opts) do
     size = bit_size(bitstring)
     <<h::size(size)>> = bitstring
-    concat(Inspect.Integer.inspect(h, opts), "::size(" <> Integer.to_string(size) <> ")")
+    Inspect.Integer.inspect(h, opts) <> "::size(" <> Integer.to_string(size) <> ")"
   end
 
   @compile {:inline, decrement: 1}
@@ -222,7 +142,7 @@ defimpl Inspect, for: List do
     color("[]", :list, opts)
   end
 
-  # TODO: Remove :char_list and :as_char_lists handling on v2.0
+  # TODO: Remove :char_list and :as_char_lists handling in 2.0
   def inspect(term, opts) do
     %Inspect.Opts{
       charlists: lists,
@@ -262,7 +182,7 @@ defimpl Inspect, for: List do
             {escaped, _} -> [?', escaped, ?', " ++ ..."]
           end
 
-        color(IO.iodata_to_binary(inspected), :charlist, opts)
+        IO.iodata_to_binary(inspected)
 
       keyword?(term) ->
         container_doc(open, term, close, opts, &keyword/2, separator: sep, break: :strict)
@@ -274,7 +194,7 @@ defimpl Inspect, for: List do
 
   @doc false
   def keyword({key, value}, opts) do
-    key = color(Macro.inspect_atom(:key, key), :atom, opts)
+    key = color(Identifier.inspect_as_key(key), :atom, opts)
     concat(key, concat(" ", to_doc(value, opts)))
   end
 
@@ -302,33 +222,28 @@ end
 
 defimpl Inspect, for: Map do
   def inspect(map, opts) do
-    list = Map.to_list(map)
-
-    fun =
-      if Inspect.List.keyword?(list) do
-        &Inspect.List.keyword/2
-      else
-        sep = color(" => ", :map, opts)
-        &to_assoc(&1, &2, sep)
-      end
-
-    map_container_doc(list, "", opts, fun)
+    inspect(map, "", opts)
   end
 
-  def inspect(map, name, infos, opts) do
-    fun = fn %{field: field}, opts -> Inspect.List.keyword({field, Map.get(map, field)}, opts) end
-    map_container_doc(infos, name, opts, fun)
-  end
-
-  defp to_assoc({key, value}, opts, sep) do
-    concat(concat(to_doc(key, opts), sep), to_doc(value, opts))
-  end
-
-  defp map_container_doc(list, name, opts, fun) do
+  def inspect(map, name, opts) do
+    map = :maps.to_list(map)
     open = color("%" <> name <> "{", :map, opts)
     sep = color(",", :map, opts)
     close = color("}", :map, opts)
-    container_doc(open, list, close, opts, fun, separator: sep, break: :strict)
+    container_doc(open, map, close, opts, traverse_fun(map, opts), separator: sep, break: :strict)
+  end
+
+  defp traverse_fun(list, opts) do
+    if Inspect.List.keyword?(list) do
+      &Inspect.List.keyword/2
+    else
+      sep = color(" => ", :map, opts)
+      &to_map(&1, &2, sep)
+    end
+  end
+
+  defp to_map({key, value}, opts, sep) do
+    concat(concat(to_doc(key, opts), sep), to_doc(value, opts))
   end
 end
 
@@ -366,46 +281,19 @@ defimpl Inspect, for: Integer do
 end
 
 defimpl Inspect, for: Float do
-  def inspect(float, opts) do
-    abs = abs(float)
-
-    formatted =
-      if abs >= 1.0 and abs < 1.0e16 and trunc(float) == float do
-        [Integer.to_string(trunc(float)), ?., ?0]
-      else
-        :io_lib_format.fwrite_g(float)
-      end
-
-    color(IO.iodata_to_binary(formatted), :number, opts)
+  def inspect(term, opts) do
+    inspected = IO.iodata_to_binary(:io_lib_format.fwrite_g(term))
+    color(inspected, :number, opts)
   end
 end
 
 defimpl Inspect, for: Regex do
-  def inspect(regex = %{opts: regex_opts}, opts) when is_list(regex_opts) do
-    concat([
-      "Regex.compile!(",
-      Inspect.BitString.inspect(regex.source, opts),
-      ", ",
-      Inspect.List.inspect(regex_opts, opts),
-      ")"
-    ])
-  end
-
   def inspect(regex, opts) do
-    {escaped, _} =
-      regex.source
-      |> normalize(<<>>)
-      |> Identifier.escape(?/, :infinity, &escape_map/1)
-
+    {escaped, _} = Identifier.escape(regex.source, ?/, :infinity, &escape_map/1)
     source = IO.iodata_to_binary(['~r/', escaped, ?/, regex.opts])
     color(source, :regex, opts)
   end
 
-  defp normalize(<<?\\, ?\\, rest::binary>>, acc), do: normalize(rest, <<acc::binary, ?\\, ?\\>>)
-  defp normalize(<<?\\, ?/, rest::binary>>, acc), do: normalize(rest, <<acc::binary, ?/>>)
-  defp normalize(<<char, rest::binary>>, acc), do: normalize(rest, <<acc::binary, char>>)
-  defp normalize(<<>>, acc), do: acc
-
   defp escape_map(?\a), do: '\\a'
   defp escape_map(?\f), do: '\\f'
   defp escape_map(?\n), do: '\\n'
@@ -422,12 +310,9 @@ defimpl Inspect, for: Function do
     name = fun_info[:name]
 
     cond do
-      not is_atom(mod) ->
-        "#Function<#{uniq(fun_info)}/#{fun_info[:arity]}>"
-
       fun_info[:type] == :external and fun_info[:env] == [] ->
-        inspected_as_atom = Macro.inspect_atom(:literal, mod)
-        inspected_as_function = Macro.inspect_atom(:remote_call, name)
+        inspected_as_atom = Identifier.inspect_as_atom(mod)
+        inspected_as_function = Identifier.inspect_as_function(name)
         "&#{inspected_as_atom}.#{inspected_as_function}/#{fun_info[:arity]}"
 
       match?('elixir_compiler_' ++ _, Atom.to_charlist(mod)) ->
@@ -443,7 +328,7 @@ defimpl Inspect, for: Function do
   end
 
   defp default_inspect(mod, fun_info) do
-    inspected_as_atom = Macro.inspect_atom(:literal, mod)
+    inspected_as_atom = Identifier.inspect_as_atom(mod)
     extracted_name = extract_name(fun_info[:name])
     "#Function<#{uniq(fun_info)}/#{fun_info[:arity]} in #{inspected_as_atom}#{extracted_name}>"
   end
@@ -455,10 +340,10 @@ defimpl Inspect, for: Function do
   defp extract_name(name) do
     case Identifier.extract_anonymous_fun_parent(name) do
       {name, arity} ->
-        "." <> Macro.inspect_atom(:remote_call, name) <> "/" <> arity
+        "." <> Identifier.inspect_as_function(name) <> "/" <> arity
 
       :error ->
-        "." <> Macro.inspect_atom(:remote_call, name)
+        "." <> Identifier.inspect_as_function(name)
     end
   end
 
@@ -467,36 +352,6 @@ defimpl Inspect, for: Function do
   end
 end
 
-defimpl Inspect, for: Inspect.Error do
-  @impl true
-  def inspect(%{stacktrace: stacktrace} = inspect_error, _opts) do
-    message = Exception.message(inspect_error)
-    format_output(message, stacktrace)
-  end
-
-  defp format_output(message, [_ | _] = stacktrace) do
-    stacktrace = Exception.format_stacktrace(stacktrace)
-
-    """
-    #Inspect.Error<
-    #{Inspect.Error.pad(message, 2)}
-
-      Stacktrace:
-
-    #{stacktrace}
-    >\
-    """
-  end
-
-  defp format_output(message, []) do
-    """
-    #Inspect.Error<
-      #{Inspect.Error.pad(message, 2)}
-    >\
-    """
-  end
-end
-
 defimpl Inspect, for: PID do
   def inspect(pid, _opts) do
     "#PID" <> IO.iodata_to_binary(:erlang.pid_to_list(pid))
@@ -517,123 +372,20 @@ defimpl Inspect, for: Reference do
 end
 
 defimpl Inspect, for: Any do
-  defmacro __deriving__(module, struct, options) do
-    fields = Map.keys(struct) -- [:__exception__, :__struct__]
-    only = Keyword.get(options, :only, fields)
-    except = Keyword.get(options, :except, [])
-    optional = Keyword.get(options, :optional, [])
-
-    :ok = validate_option(:only, only, fields, module)
-    :ok = validate_option(:except, except, fields, module)
-    :ok = validate_option(:optional, optional, fields, module)
-
-    inspect_module =
-      if fields == only and except == [] do
-        Inspect.Map
-      else
-        Inspect.Any
-      end
-
-    filtered_fields =
-      fields
-      |> Enum.reject(&(&1 in except))
-      |> Enum.filter(&(&1 in only))
-
-    optional? =
-      if optional == [] do
-        false
-      else
-        optional_map = for field <- optional, into: %{}, do: {field, Map.fetch!(struct, field)}
-
-        quote do
-          case unquote(Macro.escape(optional_map)) do
-            %{^var!(field) => var!(default)} ->
-              var!(default) == Map.get(var!(struct), var!(field))
-
-            %{} ->
-              false
-          end
-        end
-      end
-
-    quote do
-      defimpl Inspect, for: unquote(module) do
-        def inspect(var!(struct), var!(opts)) do
-          var!(infos) =
-            for %{field: var!(field)} = var!(info) <- unquote(module).__info__(:struct),
-                var!(field) in unquote(filtered_fields) and not unquote(optional?),
-                do: var!(info)
-
-          var!(name) = Macro.inspect_atom(:literal, unquote(module))
-          unquote(inspect_module).inspect(var!(struct), var!(name), var!(infos), var!(opts))
-        end
-      end
-    end
-  end
-
-  defp validate_option(option, option_list, fields, module) do
-    case option_list -- fields do
-      [] ->
-        :ok
-
-      unknown_fields ->
-        raise ArgumentError,
-              "unknown fields #{Kernel.inspect(unknown_fields)} in #{Kernel.inspect(option)} " <>
-                "when deriving the Inspect protocol for #{Kernel.inspect(module)}"
-    end
-  end
-
   def inspect(%module{} = struct, opts) do
     try do
-      {module.__struct__(), module.__info__(:struct)}
+      module.__struct__
     rescue
       _ -> Inspect.Map.inspect(struct, opts)
     else
-      {dunder, fields} ->
-        if Map.keys(dunder) == Map.keys(struct) do
-          infos =
-            for %{field: field} = info <- fields,
-                field not in [:__struct__, :__exception__],
-                do: info
-
-          Inspect.Map.inspect(struct, Macro.inspect_atom(:literal, module), infos, opts)
+      dunder ->
+        if :maps.keys(dunder) == :maps.keys(struct) do
+          pruned = :maps.remove(:__exception__, :maps.remove(:__struct__, struct))
+          colorless_opts = %{opts | syntax_colors: []}
+          Inspect.Map.inspect(pruned, Inspect.Atom.inspect(module, colorless_opts), opts)
         else
           Inspect.Map.inspect(struct, opts)
         end
     end
   end
-
-  def inspect(map, name, infos, opts) do
-    open = color("#" <> name <> "<", :map, opts)
-    sep = color(",", :map, opts)
-    close = color(">", :map, opts)
-
-    fun = fn
-      %{field: field}, opts -> Inspect.List.keyword({field, Map.get(map, field)}, opts)
-      :..., _opts -> "..."
-    end
-
-    container_doc(open, infos ++ [:...], close, opts, fun, separator: sep, break: :strict)
-  end
 end
-
-require Protocol
-
-Protocol.derive(
-  Inspect,
-  Macro.Env,
-  only: [
-    :module,
-    :file,
-    :line,
-    :function,
-    :context,
-    :aliases,
-    :requires,
-    :functions,
-    :macros,
-    :macro_aliases,
-    :context_modules,
-    :lexical_tracker
-  ]
-)

lib/elixir/lib/inspect/algebra.ex

@@ -1,165 +1,97 @@
 defmodule Inspect.Opts do
   @moduledoc """
-  Defines the options used by the `Inspect` protocol.
+  Defines the Inspect.Opts used by the Inspect protocol.
 
   The following fields are available:
 
+    * `:structs` - when `false`, structs are not formatted by the inspect
+      protocol, they are instead printed as maps, defaults to `true`.
+
+    * `:binaries` - when `:as_strings` all binaries will be printed as strings,
+      non-printable bytes will be escaped.
+
+      When `:as_binaries` all binaries will be printed in bit syntax.
+
+      When the default `:infer`, the binary will be printed as a string if it
+      is printable, otherwise in bit syntax.
+
+    * `:charlists` - when `:as_charlists` all lists will be printed as char
+      lists, non-printable elements will be escaped.
+
+      When `:as_lists` all lists will be printed as lists.
+
+      When the default `:infer`, the list will be printed as a charlist if it
+      is printable, otherwise as list.
+
+    * `:limit` - limits the number of items that are printed for tuples,
+      bitstrings, maps, lists and any other collection of items. It does not
+      apply to strings nor charlists and defaults to 50. If you don't want to limit
+      the number of items to a particular number, use `:infinity`.
+
+    * `:printable_limit` - limits the number of bytes that are printed for strings
+      and char lists. Defaults to 4096. If you don't want to limit the number of items
+      to a particular number, use `:infinity`.
+
+    * `:pretty` - if set to `true` enables pretty printing, defaults to `false`.
+
+    * `:width` - defaults to 80 characters, used when pretty is `true` or when
+      printing to IO devices. Set to 0 to force each item to be printed on its
+      own line. If you don't want to limit the number of items to a particular
+      number, use `:infinity`.
+
     * `:base` - prints integers as `:binary`, `:octal`, `:decimal`, or `:hex`,
       defaults to `:decimal`. When inspecting binaries any `:base` other than
       `:decimal` implies `binaries: :as_binaries`.
 
-    * `:binaries` - when `:as_binaries` all binaries will be printed in bit
-      syntax.
-
-      When `:as_strings` all binaries will be printed as strings, non-printable
-      bytes will be escaped.
-
-      When the default `:infer`, the binary will be printed as a string if it
-      is printable, otherwise in bit syntax. See `String.printable?/1` to learn
-      when a string is printable.
-
-    * `:charlists` - when `:as_charlists` all lists will be printed as charlists,
-      non-printable elements will be escaped.
-
-      When `:as_lists` all lists will be printed as lists.
-
-      When the default `:infer`, the list will be printed as a charlist if it
-      is printable, otherwise as list. See `List.ascii_printable?/1` to learn
-      when a charlist is printable.
-
-    * `:custom_options` (since v1.9.0) - a keyword list storing custom user-defined
-      options. Useful when implementing the `Inspect` protocol for nested structs
-      to pass the custom options through.
-
-    * `:inspect_fun` (since v1.9.0) - a function to build algebra documents.
-      Defaults to `Inspect.Opts.default_inspect_fun/0`.
-
-    * `:limit` - limits the number of items that are inspected for tuples,
-      bitstrings, maps, lists and any other collection of items, with the exception of
-      printable strings and printable charlists which use the `:printable_limit` option.
-      If you don't want to limit the number of items to a particular number,
-      use `:infinity`. It accepts a positive integer or `:infinity`.
-      Defaults to `50`.
-
-    * `:pretty` - if set to `true` enables pretty printing. Defaults to `false`.
-
-    * `:printable_limit` - limits the number of characters that are inspected
-      on printable strings and printable charlists. You can use `String.printable?/1`
-      and `List.ascii_printable?/1` to check if a given string or charlist is
-      printable. If you don't want to limit the number of characters to a particular
-      number, use `:infinity`. It accepts a positive integer or `:infinity`.
-      Defaults to `4096`.
-
     * `:safe` - when `false`, failures while inspecting structs will be raised
       as errors instead of being wrapped in the `Inspect.Error` exception. This
       is useful when debugging failures and crashes for custom inspect
-      implementations. Defaults to `true`.
+      implementations
 
-    * `:structs` - when `false`, structs are not formatted by the inspect
-      protocol, they are instead printed as maps. Defaults to `true`.
-
-    * `:syntax_colors` - when set to a keyword list of colors the output is
-      colorized. The keys are types and the values are the colors to use for
+    * `:syntax_colors` - when set to a keyword list of colors the output will
+      be colorized. The keys are types and the values are the colors to use for
       each type (for example, `[number: :red, atom: :blue]`). Types can include
-      `:atom`, `:binary`, `:boolean`, `:list`, `:map`, `:number`, `:regex`,
-      `:string`, and `:tuple`. Custom data types may provide their own options.
+      `:number`, `:atom`, `regex`, `:tuple`, `:map`, `:list`, and `:reset`.
       Colors can be any `t:IO.ANSI.ansidata/0` as accepted by `IO.ANSI.format/1`.
-      A default list of colors can be retrieved from `IO.ANSI.syntax_colors/0`.
-
-    * `:width` - number of characters per line used when pretty is `true` or when
-      printing to IO devices. Set to `0` to force each item to be printed on its
-      own line. If you don't want to limit the number of items to a particular
-      number, use `:infinity`. Defaults to `80`.
 
   """
 
-  # TODO: Remove :char_lists key on v2.0
-  defstruct base: :decimal,
+  # TODO: Remove :char_lists key by 2.0
+  defstruct structs: true,
             binaries: :infer,
-            char_lists: :infer,
             charlists: :infer,
-            custom_options: [],
-            inspect_fun: &Inspect.inspect/2,
+            char_lists: :infer,
             limit: 50,
-            pretty: false,
             printable_limit: 4096,
+            width: 80,
+            base: :decimal,
+            pretty: false,
             safe: true,
-            structs: true,
-            syntax_colors: [],
-            width: 80
+            syntax_colors: []
 
   @type color_key :: atom
 
+  # TODO: Remove :char_lists key and :as_char_lists value by 2.0
   @type t :: %__MODULE__{
-          base: :decimal | :binary | :hex | :octal,
+          structs: boolean,
           binaries: :infer | :as_binaries | :as_strings,
           charlists: :infer | :as_lists | :as_charlists,
-          custom_options: keyword,
-          inspect_fun: (any, t -> Inspect.Algebra.t()),
-          limit: non_neg_integer | :infinity,
+          char_lists: :infer | :as_lists | :as_char_lists,
+          limit: pos_integer | :infinity,
+          printable_limit: pos_integer | :infinity,
+          width: pos_integer | :infinity,
+          base: :decimal | :binary | :hex | :octal,
           pretty: boolean,
-          printable_limit: non_neg_integer | :infinity,
           safe: boolean,
-          structs: boolean,
-          syntax_colors: [{color_key, IO.ANSI.ansidata()}],
-          width: non_neg_integer | :infinity
+          syntax_colors: [{color_key, IO.ANSI.ansidata()}]
         }
+end
 
-  @doc """
-  Builds an `Inspect.Opts` struct.
+defmodule Inspect.Error do
+  @moduledoc """
+  Raised when a struct cannot be inspected.
   """
-  @doc since: "1.13.0"
-  @spec new(keyword()) :: t
-  def new(opts) do
-    struct(%Inspect.Opts{inspect_fun: default_inspect_fun()}, opts)
-  end
-
-  @doc """
-  Returns the default inspect function.
-  """
-  @doc since: "1.13.0"
-  @spec default_inspect_fun() :: (term, t -> Inspect.Algebra.t())
-  def default_inspect_fun do
-    :persistent_term.get({__MODULE__, :inspect_fun}, &Inspect.inspect/2)
-  end
-
-  @doc """
-  Sets the default inspect function.
-
-  Set this option with care as it will change how all values
-  in the system are inspected. The main use of this functionality
-  is to provide an entry point to filter inspected values,
-  in order for entities to comply with rules and legislations
-  on data security and data privacy.
-
-  It is **extremely discouraged** for libraries to set their own
-  function as this must be controlled by applications. Libraries
-  should instead define their own structs with custom inspect
-  implementations. If a library must change the default inspect
-  function, then it is best to define to ask users of your library
-  to explicitly call `default_inspect_fun/1` with your function of
-  choice.
-
-  The default is `Inspect.inspect/2`.
-
-  ## Examples
-
-      previous_fun = Inspect.Opts.default_inspect_fun()
-
-      Inspect.Opts.default_inspect_fun(fn
-        %{address: _} = map, opts ->
-          previous_fun.(%{map | address: "[REDACTED]"}, opts)
-
-        value, opts ->
-          previous_fun.(value, opts)
-      end)
-
-  """
-  @doc since: "1.13.0"
-  @spec default_inspect_fun((term, t -> Inspect.Algebra.t())) :: :ok
-  def default_inspect_fun(fun) when is_function(fun, 2) do
-    :persistent_term.put({__MODULE__, :inspect_fun}, fun)
-  end
+  defexception [:message]
 end
 
 defmodule Inspect.Algebra do
@@ -198,7 +130,7 @@ defmodule Inspect.Algebra do
       iex> Inspect.Algebra.format(doc, 80)
       ["a", " ", "b"]
 
-  Note that the break was represented as is, because we haven't reached
+  Notice the break was represented as is, because we haven't reached
   a line limit. Once we do, it is replaced by a newline:
 
       iex> doc = Inspect.Algebra.glue(String.duplicate("a", 20), " ", "b")
@@ -216,7 +148,7 @@ defmodule Inspect.Algebra do
 
   ## Implementation details
 
-  The implementation of `Inspect.Algebra` is based on the Strictly Pretty
+  The implementation of Inspect.Algebra is based on the Strictly Pretty
   paper by [Lindig][0] which builds on top of previous pretty printing
   algorithms but is tailored to strict languages, such as Elixir.
   The core idea in the paper is the use of explicit document groups which
@@ -243,29 +175,23 @@ defmodule Inspect.Algebra do
 
   @type t ::
           binary
-          | :doc_line
           | :doc_nil
-          | doc_break
-          | doc_collapse
-          | doc_color
-          | doc_cons
-          | doc_fits
-          | doc_force
-          | doc_group
-          | doc_nest
+          | :doc_line
           | doc_string
-          | doc_limit
+          | doc_cons
+          | doc_nest
+          | doc_break
+          | doc_group
+          | doc_color
+          | doc_force
+          | doc_fits
+          | doc_collapse
 
   @typep doc_string :: {:doc_string, t, non_neg_integer}
   defmacrop doc_string(string, length) do
     quote do: {:doc_string, unquote(string), unquote(length)}
   end
 
-  @typep doc_limit :: {:doc_limit, t, pos_integer | :infinity}
-  defmacrop doc_limit(doc, limit) do
-    quote do: {:doc_limit, unquote(doc), unquote(limit)}
-  end
-
   @typep doc_cons :: {:doc_cons, t, t}
   defmacrop doc_cons(left, right) do
     quote do: {:doc_cons, unquote(left), unquote(right)}
@@ -307,25 +233,21 @@ defmodule Inspect.Algebra do
   end
 
   @docs [
-    :doc_break,
-    :doc_collapse,
-    :doc_color,
-    :doc_cons,
-    :doc_fits,
-    :doc_force,
-    :doc_group,
-    :doc_nest,
     :doc_string,
-    :doc_limit
+    :doc_cons,
+    :doc_nest,
+    :doc_break,
+    :doc_group,
+    :doc_color,
+    :doc_force,
+    :doc_fits,
+    :doc_collapse
   ]
 
   defguard is_doc(doc)
            when is_binary(doc) or doc in [:doc_nil, :doc_line] or
                   (is_tuple(doc) and elem(doc, 0) in @docs)
 
-  defguardp is_limit(limit) when limit == :infinity or (is_integer(limit) and limit >= 0)
-  defguardp is_width(limit) when limit == :infinity or (is_integer(limit) and limit >= 0)
-
   # Elixir + Inspect.Opts conveniences
 
   @doc """
@@ -335,10 +257,10 @@ defmodule Inspect.Algebra do
   @spec to_doc(any, Inspect.Opts.t()) :: t
   def to_doc(term, opts)
 
-  def to_doc(%_{} = struct, %Inspect.Opts{inspect_fun: fun} = opts) do
+  def to_doc(%_{} = struct, %Inspect.Opts{} = opts) do
     if opts.structs do
       try do
-        fun.(struct, opts)
+        Inspect.inspect(struct, opts)
       rescue
         caught_exception ->
           # Because we try to raise a nice error message in case
@@ -353,28 +275,19 @@ defmodule Inspect.Algebra do
             try do
               Process.put(:inspect_trap, true)
 
-              inspected_struct =
-                struct
-                |> Inspect.Map.inspect(%{
-                  opts
-                  | syntax_colors: [],
-                    inspect_fun: Inspect.Opts.default_inspect_fun()
-                })
-                |> format(opts.width)
-                |> IO.iodata_to_binary()
+              res = Inspect.Map.inspect(struct, %{opts | syntax_colors: []})
+              res = IO.iodata_to_binary(format(res, :infinity))
 
-              inspect_error =
-                Inspect.Error.exception(
-                  exception: caught_exception,
-                  stacktrace: __STACKTRACE__,
-                  inspected_struct: inspected_struct
-                )
+              message =
+                "got #{inspect(caught_exception.__struct__)} with message " <>
+                  "#{inspect(Exception.message(caught_exception))} while inspecting #{res}"
+
+              exception = Inspect.Error.exception(message: message)
 
               if opts.safe do
-                opts = %{opts | inspect_fun: Inspect.Opts.default_inspect_fun()}
-                Inspect.inspect(inspect_error, opts)
+                Inspect.inspect(exception, opts)
               else
-                reraise(inspect_error, __STACKTRACE__)
+                reraise(exception, __STACKTRACE__)
               end
             after
               Process.delete(:inspect_trap)
@@ -386,8 +299,8 @@ defmodule Inspect.Algebra do
     end
   end
 
-  def to_doc(arg, %Inspect.Opts{inspect_fun: fun} = opts) do
-    fun.(arg, opts)
+  def to_doc(arg, %Inspect.Opts{} = opts) do
+    Inspect.inspect(arg, opts)
   end
 
   @doc ~S"""
@@ -399,7 +312,7 @@ defmodule Inspect.Algebra do
   attempts to put as much as possible on the same line. If they are not simple,
   only one entry is shown per line if they do not fit.
 
-  The limit in the given `inspect_opts` is respected and when reached this
+  The limit in the given `Inspect.Opts` is respected and when reached this
   function stops processing and outputs `"..."` instead.
 
   ## Options
@@ -411,22 +324,18 @@ defmodule Inspect.Algebra do
 
   ## Examples
 
-      iex> inspect_opts = %Inspect.Opts{limit: :infinity}
-      iex> fun = fn i, _opts -> to_string(i) end
-      iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]", inspect_opts, fun)
+      iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]",
+      ...>         %Inspect.Opts{limit: :infinity}, fn i, _opts -> to_string(i) end)
       iex> Inspect.Algebra.format(doc, 5) |> IO.iodata_to_binary()
       "[1,\n 2,\n 3,\n 4,\n 5]"
 
-      iex> inspect_opts = %Inspect.Opts{limit: 3}
-      iex> fun = fn i, _opts -> to_string(i) end
-      iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]", inspect_opts, fun)
+      iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]",
+      ...>         %Inspect.Opts{limit: 3}, fn i, _opts -> to_string(i) end)
       iex> Inspect.Algebra.format(doc, 20) |> IO.iodata_to_binary()
       "[1, 2, 3, ...]"
 
-      iex> inspect_opts = %Inspect.Opts{limit: 3}
-      iex> fun = fn i, _opts -> to_string(i) end
-      iex> opts = [separator: "!"]
-      iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]", inspect_opts, fun, opts)
+      iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]",
+      ...>         %Inspect.Opts{limit: 3}, fn i, _opts -> to_string(i) end, separator: "!")
       iex> Inspect.Algebra.format(doc, 20) |> IO.iodata_to_binary()
       "[1! 2! 3! ...]"
 
@@ -434,7 +343,7 @@ defmodule Inspect.Algebra do
   @doc since: "1.6.0"
   @spec container_doc(t, [any], t, Inspect.Opts.t(), (term, Inspect.Opts.t() -> t), keyword()) ::
           t
-  def container_doc(left, collection, right, inspect_opts, fun, opts \\ [])
+  def container_doc(left, collection, right, inspect, fun, opts \\ [])
       when is_doc(left) and is_list(collection) and is_doc(right) and is_function(fun, 2) and
              is_list(opts) do
     case collection do
@@ -446,7 +355,7 @@ defmodule Inspect.Algebra do
         separator = Keyword.get(opts, :separator, @container_separator)
 
         {docs, simple?} =
-          container_each(collection, inspect_opts.limit, inspect_opts, fun, [], break == :maybe)
+          container_each(collection, inspect.limit, inspect, fun, [], break == :maybe)
 
         flex? = simple? or break == :flex
         docs = fold_doc(docs, &join(&1, &2, flex?, separator))
@@ -466,15 +375,13 @@ defmodule Inspect.Algebra do
     {:lists.reverse(["..." | acc]), simple?}
   end
 
-  defp container_each([term | terms], limit, opts, fun, acc, simple?)
-       when is_list(terms) and is_limit(limit) do
-    new_limit = decrement(limit)
-    doc = fun.(term, %{opts | limit: new_limit})
-    limit = if doc == :doc_nil, do: limit, else: new_limit
+  defp container_each([term | terms], limit, opts, fun, acc, simple?) when is_list(terms) do
+    limit = decrement(limit)
+    doc = fun.(term, %{opts | limit: limit})
     container_each(terms, limit, opts, fun, [doc | acc], simple? and simple?(doc))
   end
 
-  defp container_each([left | right], limit, opts, fun, acc, simple?) when is_limit(limit) do
+  defp container_each([left | right], limit, opts, fun, acc, simple?) do
     limit = decrement(limit)
     left = fun.(left, %{opts | limit: limit})
     right = fun.(right, %{opts | limit: limit})
@@ -500,13 +407,13 @@ defmodule Inspect.Algebra do
   defp simple?(other), do: is_binary(other)
 
   @doc false
-  @deprecated "Use a combination of concat/2 and nest/2 instead"
+  # TODO: Deprecate on Elixir v1.8
   def surround(left, doc, right) when is_doc(left) and is_doc(doc) and is_doc(right) do
     concat(concat(left, nest(doc, 1)), right)
   end
 
   @doc false
-  @deprecated "Use Inspect.Algebra.container_doc/6 instead"
+  # TODO: Deprecate on Elixir v1.8
   def surround_many(
         left,
         docs,
@@ -582,10 +489,6 @@ defmodule Inspect.Algebra do
     doc_cons(doc1, doc2)
   end
 
-  def no_limit(doc) do
-    doc_limit(doc, :infinity)
-  end
-
   @doc ~S"""
   Concatenates a list of documents returning a new document.
 
@@ -605,7 +508,7 @@ defmodule Inspect.Algebra do
   Colors a document if the `color_key` has a color in the options.
   """
   @doc since: "1.4.0"
-  @spec color(t, Inspect.Opts.color_key(), Inspect.Opts.t()) :: t
+  @spec color(t, Inspect.Opts.color_key(), Inspect.Opts.t()) :: doc_color
   def color(doc, color_key, %Inspect.Opts{syntax_colors: syntax_colors}) when is_doc(doc) do
     if precolor = Keyword.get(syntax_colors, color_key) do
       postcolor = Keyword.get(syntax_colors, :reset, :reset)
@@ -635,7 +538,7 @@ defmodule Inspect.Algebra do
       ["hello", "\n     ", "world"]
 
   """
-  @spec nest(t, non_neg_integer | :cursor | :reset, :always | :break) :: doc_nest | t
+  @spec nest(t, non_neg_integer) :: doc_nest
   def nest(doc, level, mode \\ :always)
 
   def nest(doc, :cursor, mode) when is_doc(doc) and mode in [:always, :break] do
@@ -670,7 +573,7 @@ defmodule Inspect.Algebra do
       iex> Inspect.Algebra.format(doc, 80)
       ["a", "\t", "b"]
 
-  Note that the break was represented with the given string, because we didn't
+  Notice the break was represented with the given string, because we didn't
   reach a line limit. Once we do, it is replaced by a newline:
 
       iex> break = Inspect.Algebra.break("\t")
@@ -737,7 +640,7 @@ defmodule Inspect.Algebra do
 
   """
   @doc since: "1.6.0"
-  @spec next_break_fits(t, :enabled | :disabled) :: doc_fits
+  @spec next_break_fits(t) :: doc_fits
   def next_break_fits(doc, mode \\ @next_break_fits)
       when is_doc(doc) and mode in [:enabled, :disabled] do
     doc_fits(doc, mode)
@@ -777,7 +680,7 @@ defmodule Inspect.Algebra do
   to the document fitting. On the other hand, they are more expensive
   since each break needs to be re-evaluated.
 
-  This function is used by `container_doc/6` and friends to the
+  This function is used by `container_doc/4` and friends to the
   maximum number of entries on the same line.
   """
   @doc since: "1.6.0"
@@ -832,31 +735,29 @@ defmodule Inspect.Algebra do
 
   ## Examples
 
-      iex> doc =
-      ...>   Inspect.Algebra.group(
-      ...>     Inspect.Algebra.concat(
-      ...>       Inspect.Algebra.group(
-      ...>         Inspect.Algebra.concat(
-      ...>           "Hello,",
-      ...>           Inspect.Algebra.concat(
-      ...>             Inspect.Algebra.break(),
-      ...>             "A"
-      ...>           )
-      ...>         )
-      ...>       ),
+      iex> doc = Inspect.Algebra.group(
+      ...>   Inspect.Algebra.concat(
+      ...>     Inspect.Algebra.group(
       ...>       Inspect.Algebra.concat(
-      ...>         Inspect.Algebra.break(),
-      ...>         "B"
+      ...>         "Hello,",
+      ...>         Inspect.Algebra.concat(
+      ...>           Inspect.Algebra.break,
+      ...>           "A"
+      ...>         )
       ...>       )
+      ...>     ),
+      ...>     Inspect.Algebra.concat(
+      ...>       Inspect.Algebra.break,
+      ...>       "B"
       ...>     )
-      ...>   )
+      ...> ))
       iex> Inspect.Algebra.format(doc, 80)
       ["Hello,", " ", "A", " ", "B"]
       iex> Inspect.Algebra.format(doc, 6)
       ["Hello,", "\n", "A", "\n", "B"]
 
   """
-  @spec group(t, :self | :inherit) :: doc_group
+  @spec group(t) :: doc_group
   def group(doc, mode \\ :self) when is_doc(doc) do
     doc_group(doc, mode)
   end
@@ -886,8 +787,7 @@ defmodule Inspect.Algebra do
       ...>     Inspect.Algebra.concat(
       ...>       "Hughes",
       ...>       Inspect.Algebra.line()
-      ...>     ),
-      ...>     "Wadler"
+      ...>     ), "Wadler"
       ...>   )
       iex> Inspect.Algebra.format(doc, 80)
       ["Hughes", "\n", "Wadler"]
@@ -900,7 +800,7 @@ defmodule Inspect.Algebra do
   @doc ~S"""
   Inserts a mandatory linebreak between two documents.
 
-  See `line/0`.
+  See `line/1`.
 
   ## Examples
 
@@ -922,10 +822,9 @@ defmodule Inspect.Algebra do
   ## Examples
 
       iex> docs = ["A", "B", "C"]
-      iex> docs =
-      ...>   Inspect.Algebra.fold_doc(docs, fn doc, acc ->
-      ...>     Inspect.Algebra.concat([doc, "!", acc])
-      ...>   end)
+      iex> docs = Inspect.Algebra.fold_doc(docs, fn(doc, acc) ->
+      ...>   Inspect.Algebra.concat([doc, "!", acc])
+      ...> end)
       iex> Inspect.Algebra.format(docs, 80)
       ["A", "!", "B", "!", "C"]
 
@@ -959,30 +858,24 @@ defmodule Inspect.Algebra do
 
   """
   @spec format(t, non_neg_integer | :infinity) :: iodata
-  def format(doc, width) when is_doc(doc) and is_width(width) do
+  def format(doc, width) when is_doc(doc) and (width == :infinity or width >= 0) do
     format(width, 0, [{0, :flat, doc}])
   end
 
-  # Type representing the document mode to be rendered:
+  # Type representing the document mode to be rendered
   #
   #   * flat - represents a document with breaks as flats (a break may fit, as it may break)
   #   * break - represents a document with breaks as breaks (a break always fits, since it breaks)
   #
-  # The following modes are exclusive to fitting:
+  # The following modes are exclusive to fitting
   #
   #   * flat_no_break - represents a document with breaks as flat not allowed to enter in break mode
   #   * break_no_flat - represents a document with breaks as breaks not allowed to enter in flat mode
   #
-  @typep mode :: :flat | :flat_no_break | :break | :break_no_flat
+  @typep mode :: :flat | :flat_no_break | :break
 
-  @spec fits?(
-          width :: non_neg_integer() | :infinity,
-          column :: non_neg_integer(),
-          break? :: boolean(),
-          entries
-        ) :: boolean()
-        when entries:
-               maybe_improper_list({integer(), mode(), t()}, {:tail, boolean(), entries} | [])
+  @spec fits?(width :: integer(), column :: integer(), break? :: boolean(), entries) :: boolean()
+        when entries: [{integer(), mode(), t()}] | {:tail, boolean(), entries}
 
   # We need at least a break to consider the document does not fit since a
   # large document without breaks has no option but fitting its current line.
@@ -1041,17 +934,7 @@ defmodule Inspect.Algebra do
   defp fits?(w, k, b?, [{i, m, doc_group(x, _)} | t]),
     do: fits?(w, k, b?, [{i, m, x} | {:tail, b?, t}])
 
-  defp fits?(w, k, b?, [{i, m, doc_limit(x, :infinity)} | t]) when w != :infinity,
-    do: fits?(:infinity, k, b?, [{i, :flat, x}, {i, m, doc_limit(empty(), w)} | t])
-
-  defp fits?(_w, k, b?, [{i, m, doc_limit(x, w)} | t]),
-    do: fits?(w, k, b?, [{i, m, x} | t])
-
-  @spec format(
-          width :: non_neg_integer() | :infinity,
-          column :: non_neg_integer(),
-          [{integer, mode, t}]
-        ) :: [binary]
+  @spec format(integer | :infinity, integer, [{integer, mode, t}]) :: [binary]
   defp format(_, _, []), do: []
   defp format(w, k, [{_, _, :doc_nil} | t]), do: format(w, k, t)
   defp format(w, _, [{i, _, :doc_line} | t]), do: [indent(i) | format(w, i, t)]
@@ -1105,15 +988,6 @@ defmodule Inspect.Algebra do
     end
   end
 
-  # Limit is set to infinity and then reverts
-  defp format(w, k, [{i, m, doc_limit(x, :infinity)} | t]) when w != :infinity do
-    format(:infinity, k, [{i, :flat, x}, {i, m, doc_limit(empty(), w)} | t])
-  end
-
-  defp format(_w, k, [{i, m, doc_limit(x, w)} | t]) do
-    format(w, k, [{i, m, x} | t])
-  end
-
   defp collapse(["\n" <> _ | t], max, count, i) do
     collapse(t, max, count + 1, i)
   end

lib/elixir/lib/integer.ex

@@ -4,11 +4,11 @@ defmodule Integer do
 
   Some functions that work on integers are found in `Kernel`:
 
-    * `Kernel.abs/1`
-    * `Kernel.div/2`
-    * `Kernel.max/2`
-    * `Kernel.min/2`
-    * `Kernel.rem/2`
+    * `abs/2`
+    * `div/2`
+    * `max/2`
+    * `min/2`
+    * `rem/2`
 
   """
 
@@ -64,53 +64,10 @@ defmodule Integer do
   """
   defguard is_even(integer) when is_integer(integer) and (integer &&& 1) == 0
 
-  @doc """
-  Computes `base` raised to power of `exponent`.
-
-  Both `base` and `exponent` must be integers.
-  The exponent must be zero or positive.
-
-  See `Float.pow/2` for exponentiation of negative
-  exponents as well as floats.
-
-  ## Examples
-
-      iex> Integer.pow(2, 0)
-      1
-      iex> Integer.pow(2, 1)
-      2
-      iex> Integer.pow(2, 10)
-      1024
-      iex> Integer.pow(2, 11)
-      2048
-      iex> Integer.pow(2, 64)
-      0x10000000000000000
-
-      iex> Integer.pow(3, 4)
-      81
-      iex> Integer.pow(4, 3)
-      64
-
-      iex> Integer.pow(-2, 3)
-      -8
-      iex> Integer.pow(-2, 4)
-      16
-
-      iex> Integer.pow(2, -2)
-      ** (ArithmeticError) bad argument in arithmetic expression
-
-  """
-  @doc since: "1.12.0"
-  @spec pow(integer, non_neg_integer) :: integer
-  def pow(base, exponent) when is_integer(base) and is_integer(exponent) do
-    if exponent < 0, do: :erlang.error(:badarith, [base, exponent])
-    base ** exponent
-  end
-
   @doc """
   Computes the modulo remainder of an integer division.
 
-  This function performs a [floored division](`floor_div/2`), which means that
+  `Integer.mod/2` uses floored division, which means that
   the result will always have the sign of the `divisor`.
 
   Raises an `ArithmeticError` exception if one of the arguments is not an
@@ -142,8 +99,8 @@ defmodule Integer do
   Raises an `ArithmeticError` exception if one of the arguments is not an
   integer, or when the `divisor` is `0`.
 
-  This function performs a *floored* integer division, which means that
-  the result will always be rounded towards negative infinity.
+  `Integer.floor_div/2` performs *floored* integer division. This means that
+  the result is always rounded towards negative infinity.
 
   If you want to perform truncated integer division (rounding towards zero),
   use `Kernel.div/2` instead.
@@ -201,7 +158,7 @@ defmodule Integer do
   Returns the integer represented by the ordered `digits`.
 
   An optional `base` value may be provided representing the radix for the `digits`.
-  Base has to be an integer greater than or equal to `2`.
+  Base has to be an integer greater or equal than `2`.
 
   ## Examples
 
@@ -269,14 +226,14 @@ defmodule Integer do
       ** (ArgumentError) invalid base 38
 
   """
-  @spec parse(binary, 2..36) :: {integer, remainder_of_binary :: binary} | :error
+  @spec parse(binary, 2..36) :: {integer, binary} | :error
   def parse(binary, base \\ 10)
 
   def parse(_binary, base) when base not in 2..36 do
     raise ArgumentError, "invalid base #{inspect(base)}"
   end
 
-  def parse(binary, base) when is_binary(binary) do
+  def parse(binary, base) do
     case count_digits(binary, base) do
       0 ->
         :error
@@ -287,14 +244,14 @@ defmodule Integer do
     end
   end
 
-  defp count_digits(<<sign, rest::bits>>, base) when sign in '+-' do
+  defp count_digits(<<sign, rest::binary>>, base) when sign in '+-' do
     case count_digits_nosign(rest, base, 1) do
       1 -> 0
       count -> count
     end
   end
 
-  defp count_digits(<<rest::bits>>, base) do
+  defp count_digits(<<rest::binary>>, base) do
     count_digits_nosign(rest, base, 0)
   end
 
@@ -304,20 +261,17 @@ defmodule Integer do
       char <- chars do
     digit = char + diff
 
-    defp count_digits_nosign(<<unquote(char), rest::bits>>, base, count)
+    defp count_digits_nosign(<<unquote(char), rest::binary>>, base, count)
          when base > unquote(digit) do
       count_digits_nosign(rest, base, count + 1)
     end
   end
 
-  defp count_digits_nosign(<<_::bits>>, _, count), do: count
+  defp count_digits_nosign(<<_::binary>>, _, count), do: count
 
   @doc """
   Returns a binary which corresponds to the text representation
-  of `integer` in the given `base`.
-
-  `base` can be an integer between 2 and 36. If no `base` is given,
-  it defaults to `10`.
+  of `integer`.
 
   Inlined by the compiler.
 
@@ -335,6 +289,22 @@ defmodule Integer do
       iex> Integer.to_string(0123)
       "123"
 
+  """
+  @spec to_string(integer) :: String.t()
+  def to_string(integer) do
+    :erlang.integer_to_binary(integer)
+  end
+
+  @doc """
+  Returns a binary which corresponds to the text representation
+  of `integer` in the given `base`.
+
+  `base` can be an integer between 2 and 36.
+
+  Inlined by the compiler.
+
+  ## Examples
+
       iex> Integer.to_string(100, 16)
       "64"
 
@@ -346,16 +316,12 @@ defmodule Integer do
 
   """
   @spec to_string(integer, 2..36) :: String.t()
-  def to_string(integer, base \\ 10) do
+  def to_string(integer, base) do
     :erlang.integer_to_binary(integer, base)
   end
 
   @doc """
-  Returns a charlist which corresponds to the text representation
-  of `integer` in the given `base`.
-
-  `base` can be an integer between 2 and 36. If no `base` is given,
-  it defaults to `10`.
+  Returns a charlist which corresponds to the text representation of the given `integer`.
 
   Inlined by the compiler.
 
@@ -373,6 +339,21 @@ defmodule Integer do
       iex> Integer.to_charlist(0123)
       '123'
 
+  """
+  @spec to_charlist(integer) :: charlist
+  def to_charlist(integer) do
+    :erlang.integer_to_list(integer)
+  end
+
+  @doc """
+  Returns a charlist which corresponds to the text representation of `integer` in the given `base`.
+
+  `base` can be an integer between 2 and 36.
+
+  Inlined by the compiler.
+
+  ## Examples
+
       iex> Integer.to_charlist(100, 16)
       '64'
 
@@ -384,7 +365,7 @@ defmodule Integer do
 
   """
   @spec to_charlist(integer, 2..36) :: charlist
-  def to_charlist(integer, base \\ 10) do
+  def to_charlist(integer, base) do
     :erlang.integer_to_list(integer, base)
   end
 
@@ -418,7 +399,8 @@ defmodule Integer do
 
   """
   @doc since: "1.5.0"
-  @spec gcd(integer, integer) :: non_neg_integer
+  @spec gcd(0, 0) :: 0
+  @spec gcd(integer, integer) :: pos_integer
   def gcd(integer1, integer2) when is_integer(integer1) and is_integer(integer2) do
     gcd_positive(abs(integer1), abs(integer2))
   end
@@ -427,62 +409,12 @@ defmodule Integer do
   defp gcd_positive(integer1, 0), do: integer1
   defp gcd_positive(integer1, integer2), do: gcd_positive(integer2, rem(integer1, integer2))
 
-  @doc """
-  Returns the extended greatest common divisor of the two given integers.
-
-  This function uses the extended Euclidean algorithm to return a three-element tuple with the `gcd`
-  and the coefficients `m` and `n` of Bézout's identity such that:
-
-      gcd(a, b) = m*a + n*b
-
-  By convention, `extended_gcd(0, 0)` returns `{0, 0, 0}`.
-
-  ## Examples
-
-      iex> Integer.extended_gcd(240, 46)
-      {2, -9, 47}
-      iex> Integer.extended_gcd(46, 240)
-      {2, 47, -9}
-      iex> Integer.extended_gcd(-46, 240)
-      {2, -47, -9}
-      iex> Integer.extended_gcd(-46, -240)
-      {2, -47, 9}
-
-      iex> Integer.extended_gcd(14, 21)
-      {7, -1, 1}
-
-      iex> Integer.extended_gcd(10, 0)
-      {10, 1, 0}
-      iex> Integer.extended_gcd(0, 10)
-      {10, 0, 1}
-      iex> Integer.extended_gcd(0, 0)
-      {0, 0, 0}
-
-  """
-  @doc since: "1.12.0"
-  @spec extended_gcd(integer, integer) :: {non_neg_integer, integer, integer}
-  def extended_gcd(0, 0), do: {0, 0, 0}
-  def extended_gcd(0, b), do: {b, 0, 1}
-  def extended_gcd(a, 0), do: {a, 1, 0}
-
-  def extended_gcd(integer1, integer2) when is_integer(integer1) and is_integer(integer2) do
-    extended_gcd(integer2, integer1, 0, 1, 1, 0)
-  end
-
-  defp extended_gcd(r1, r0, s1, s0, t1, t0) do
-    div = div(r0, r1)
-
-    case r0 - div * r1 do
-      0 when r1 > 0 -> {r1, s1, t1}
-      0 when r1 < 0 -> {-r1, -s1, -t1}
-      r2 -> extended_gcd(r2, r1, s0 - div * s1, s1, t0 - div * t1, t1)
-    end
-  end
-
+  # TODO: Remove by 2.0
   @doc false
   @deprecated "Use Integer.to_charlist/1 instead"
   def to_char_list(integer), do: Integer.to_charlist(integer)
 
+  # TODO: Remove by 2.0
   @doc false
   @deprecated "Use Integer.to_charlist/2 instead"
   def to_char_list(integer, base), do: Integer.to_charlist(integer, base)

lib/elixir/lib/io.ex

@@ -1,5 +1,5 @@
 defmodule IO do
-  @moduledoc ~S"""
+  @moduledoc """
   Functions handling input/output (IO).
 
   Many functions in this module expect an IO device as an argument.
@@ -7,10 +7,13 @@ defmodule IO do
   For convenience, Elixir provides `:stdio` and `:stderr` as
   shortcuts to Erlang's `:standard_io` and `:standard_error`.
 
-  The majority of the functions expect chardata. In case another type is given,
-  functions will convert those types to string via the `String.Chars` protocol
-  (as shown in typespecs). For more information on chardata, see the
-  "IO data" section below.
+  The majority of the functions expect chardata, i.e. strings or
+  lists of characters and strings. In case another type is given,
+  functions will convert to string via the `String.Chars` protocol
+  (as shown in typespecs).
+
+  The functions starting with `bin` expect iodata as an argument,
+  i.e. binaries or lists of bytes and binaries.
 
   ## IO devices
 
@@ -29,107 +32,24 @@ defmodule IO do
   was last accessed. The position of files can be changed using the
   `:file.position/2` function.
 
-  ## IO data
-
-  IO data is a data type that can be used as a more efficient alternative to binaries
-  in certain situations.
-
-  A term of type **IO data** is a binary or a list containing bytes (integers within the `0..255` range)
-  or nested IO data. The type is recursive. Let's see an example of one of
-  the possible IO data representing the binary `"hello"`:
-
-      [?h, "el", ["l", [?o]]]
-
-  The built-in `t:iodata/0` type is defined in terms of `t:iolist/0`. An IO list is
-  the same as IO data but it doesn't allow for a binary at the top level (but binaries
-  are still allowed in the list itself).
-
-  ### Use cases for IO data
-
-  IO data exists because often you need to do many append operations
-  on smaller chunks of binaries in order to create a bigger binary. However, in
-  Erlang and Elixir concatenating binaries will copy the concatenated binaries
-  into a new binary.
-
-      def email(username, domain) do
-        username <> "@" <> domain
-      end
-
-  In this function, creating the email address will copy the `username` and `domain`
-  binaries. Now imagine you want to use the resulting email inside another binary:
-
-      def welcome_message(name, username, domain) do
-        "Welcome #{name}, your email is: #{email(username, domain)}"
-      end
-
-      IO.puts(welcome_message("Meg", "meg", "example.com"))
-      #=> "Welcome Meg, your email is: meg@example.com"
-
-  Every time you concatenate binaries or use interpolation (`#{}`) you are making
-  copies of those binaries. However, in many cases you don't need the complete
-  binary while you create it, but only at the end to print it out or send it
-  somewhere. In such cases, you can construct the binary by creating IO data:
-
-      def email(username, domain) do
-        [username, ?@, domain]
-      end
-
-      def welcome_message(name, username, domain) do
-        ["Welcome ", name, ", your email is: ", email(username, domain)]
-      end
-
-      IO.puts(welcome_message("Meg", "meg", "example.com"))
-      #=> "Welcome Meg, your email is: meg@example.com"
-
-  Building IO data is cheaper than concatenating binaries. Concatenating multiple
-  pieces of IO data just means putting them together inside a list since IO data
-  can be arbitrarily nested, and that's a cheap and efficient operation. Most of
-  the IO-based APIs, such as `:gen_tcp` and `IO`, receive IO data and write it
-  to the socket directly without converting it to binary.
-
-  One drawback of IO data is that you can't do things like pattern match on the
-  first part of a piece of IO data like you can with a binary, because you usually
-  don't know the shape of the IO data. In those cases, you may need to convert it
-  to a binary by calling `iodata_to_binary/1`, which is reasonably efficient
-  since it's implemented natively in C. Other functionality, like computing the
-  length of IO data, can be computed directly on the iodata by calling `iodata_length/1`.
-
-  ### Chardata
-
-  Erlang and Elixir also have the idea of `t:chardata/0`. Chardata is very
-  similar to IO data: the only difference is that integers in IO data represent
-  bytes while integers in chardata represent Unicode code points. Bytes
-  (`t:byte/0`) are integers within the `0..255` range, while Unicode code points
-  (`t:char/0`) are integers within the `0..0x10FFFF` range. The `IO` module provides
-  the `chardata_to_string/1` function for chardata as the "counter-part" of the
-  `iodata_to_binary/1` function for IO data.
-
-  If you try to use `iodata_to_binary/1` on chardata, it will result in an
-  argument error. For example, let's try to put a code point that is not
-  representable with one byte, like `?π`, inside IO data:
-
-      IO.iodata_to_binary(["The symbol for pi is: ", ?π])
-      #=> ** (ArgumentError) argument error
-
-  If we use chardata instead, it will work as expected:
-
-      iex> IO.chardata_to_string(["The symbol for pi is: ", ?π])
-      "The symbol for pi is: π"
-
   """
 
   @type device :: atom | pid
   @type nodata :: {:error, term} | :eof
-  @type chardata :: String.t() | maybe_improper_list(char | chardata, String.t() | [])
+  @type chardata() :: :unicode.chardata()
 
-  defguardp is_device(term) when is_atom(term) or is_pid(term)
-  defguardp is_iodata(data) when is_list(data) or is_binary(data)
+  defmacrop is_iodata(data) do
+    quote do
+      is_list(unquote(data)) or is_binary(unquote(data))
+    end
+  end
 
   @doc """
   Reads from the IO `device`.
 
-  The `device` is iterated by the given number of characters, line by line if
-  `:line` is given, or until `:eof`.
+  The `device` is iterated by the given number of characters or line by line if
+  `:line` is given.
+  Alternatively, if `:all` is given, then whole `device` is returned.
 
   It returns:
 
@@ -141,24 +61,14 @@ defmodule IO do
       for instance, `{:error, :estale}` if reading from an
       NFS volume
 
+  If `:all` is given, `:eof` is never returned, but an
+  empty string in case the device has reached EOF.
   """
-  @spec read(device, :eof | :line | non_neg_integer) :: chardata | nodata
+  @spec read(device, :all | :line | non_neg_integer) :: chardata | nodata
   def read(device \\ :stdio, line_or_chars)
 
-  # TODO: Deprecate me on v1.17
   def read(device, :all) do
-    with :eof <- read(device, :eof) do
-      with [_ | _] = opts <- :io.getopts(device),
-           false <- Keyword.get(opts, :binary, true) do
-        ''
-      else
-        _ -> ""
-      end
-    end
-  end
-
-  def read(device, :eof) do
-    getn(device, '', :eof)
+    do_read_all(map_dev(device), "")
   end
 
   def read(device, :line) do
@@ -169,20 +79,20 @@ defmodule IO do
     :io.get_chars(map_dev(device), '', count)
   end
 
+  defp do_read_all(mapped_dev, acc) do
+    case :io.get_line(mapped_dev, "") do
+      line when is_binary(line) -> do_read_all(mapped_dev, acc <> line)
+      :eof -> acc
+      other -> other
+    end
+  end
+
   @doc """
   Reads from the IO `device`. The operation is Unicode unsafe.
 
-  The `device` is iterated as specified by the `line_or_chars` argument:
-
-    * if `line_or_chars` is an integer, it represents a number of bytes. The device is
-      iterated by that number of bytes.
-
-    * if `line_or_chars` is `:line`, the device is iterated line by line.
-
-    * if `line_or_chars` is `:eof`, the device is iterated until `:eof`. `line_or_chars`
-      can only be `:eof` since Elixir 1.13.0. `:eof` replaces the deprecated `:all`,
-      with the difference that `:all` returns `""` on end of file, while `:eof` returns
-      `:eof` itself.
+  The `device` is iterated by the given number of bytes or line by line if
+  `:line` is given.
+  Alternatively, if `:all` is given, then whole `device` is returned.
 
   It returns:
 
@@ -194,19 +104,17 @@ defmodule IO do
       for instance, `{:error, :estale}` if reading from an
       NFS volume
 
+  If `:all` is given, `:eof` is never returned, but an
+  empty string in case the device has reached EOF.
+
   Note: do not use this function on IO devices in Unicode mode
   as it will return the wrong result.
   """
-  @spec binread(device, :eof | :line | non_neg_integer) :: iodata | nodata
+  @spec binread(device, :all | :line | non_neg_integer) :: iodata | nodata
   def binread(device \\ :stdio, line_or_chars)
 
-  # TODO: Deprecate me on v1.17
   def binread(device, :all) do
-    with :eof <- binread(device, :eof), do: ""
-  end
-
-  def binread(device, :eof) do
-    binread_eof(map_dev(device), "")
+    do_binread_all(map_dev(device), "")
   end
 
   def binread(device, :line) do
@@ -224,53 +132,46 @@ defmodule IO do
   end
 
   @read_all_size 4096
-  defp binread_eof(mapped_dev, acc) do
+  defp do_binread_all(mapped_dev, acc) do
     case :file.read(mapped_dev, @read_all_size) do
-      {:ok, data} -> binread_eof(mapped_dev, acc <> data)
-      :eof -> if acc == "", do: :eof, else: acc
+      {:ok, data} -> do_binread_all(mapped_dev, acc <> data)
+      :eof -> acc
       other -> other
     end
   end
 
   @doc """
-  Writes `chardata` to the given `device`.
+  Writes `item` to the given `device`.
 
   By default, the `device` is the standard output.
 
   ## Examples
 
-      IO.write("sample")
+      IO.write "sample"
       #=> sample
 
-      IO.write(:stderr, "error")
+      IO.write :stderr, "error"
       #=> error
 
   """
   @spec write(device, chardata | String.Chars.t()) :: :ok
-  def write(device \\ :stdio, chardata) do
-    :io.put_chars(map_dev(device), to_chardata(chardata))
+  def write(device \\ :stdio, item) do
+    :io.put_chars(map_dev(device), to_chardata(item))
   end
 
   @doc """
-  Writes `iodata` to the given `device`.
+  Writes `item` as a binary to the given `device`.
+  No Unicode conversion happens.
+  The operation is Unicode unsafe.
 
-  This operation is meant to be used with "raw" devices
-  that are started without an encoding. The given `iodata`
-  is written as is to the device, without conversion. For
-  more information on IO data, see the "IO data" section in
-  the module documentation.
+  Check `write/2` for more information.
 
-  Use `write/2` for devices with encoding.
-
-  Important: do **not** use this function on IO devices in
-  Unicode mode as it will write the wrong data. In particular,
-  the standard IO device is set to Unicode by default, so writing
-  to stdio with this function will likely result in the wrong data
-  being sent down the wire.
+  Note: do not use this function on IO devices in Unicode mode
+  as it will return the wrong result.
   """
   @spec binwrite(device, iodata) :: :ok | {:error, term}
-  def binwrite(device \\ :stdio, iodata) when is_iodata(iodata) do
-    :file.write(map_dev(device), iodata)
+  def binwrite(device \\ :stdio, item) when is_iodata(item) do
+    :file.write(map_dev(device), item)
   end
 
   @doc """
@@ -282,99 +183,46 @@ defmodule IO do
 
   ## Examples
 
-      IO.puts("Hello World!")
+      IO.puts "Hello World!"
       #=> Hello World!
 
-      IO.puts(:stderr, "error")
+      IO.puts :stderr, "error"
       #=> error
 
   """
   @spec puts(device, chardata | String.Chars.t()) :: :ok
-  def puts(device \\ :stdio, item) when is_device(device) do
+  def puts(device \\ :stdio, item) do
     :io.put_chars(map_dev(device), [to_chardata(item), ?\n])
   end
 
   @doc """
-  Writes a `message` to stderr, along with the given `stacktrace_info`.
-
-  The `stacktrace_info` must be one of:
-
-    * a `__STACKTRACE__`, where all entries in the stacktrace will be
-      included in the error message
-
-    * a `Macro.Env` structure (since v1.14.0), where a single stacktrace
-      entry from the compilation environment will be used
-
-    * a keyword list with at least the `:file` option representing
-      a single stacktrace entry (since v1.14.0). The `:line`, `:module`,
-      `:function` options are also supported
+  Writes a `message` to stderr, along with the given `stacktrace`.
 
   This function also notifies the compiler a warning was printed
   (in case --warnings-as-errors was enabled). It returns `:ok`
   if it succeeds.
 
+  An empty list can be passed to avoid stacktrace printing.
+
   ## Examples
 
       stacktrace = [{MyApp, :main, 1, [file: 'my_app.ex', line: 4]}]
-      IO.warn("variable bar is unused", stacktrace)
+      IO.warn "variable bar is unused", stacktrace
       #=> warning: variable bar is unused
       #=>   my_app.ex:4: MyApp.main/1
 
   """
-  @spec warn(chardata | String.Chars.t(), Exception.stacktrace() | keyword() | Macro.Env.t()) ::
-          :ok
-  def warn(message, stacktrace_info)
-
+  @spec warn(chardata | String.Chars.t(), Exception.stacktrace()) :: :ok
   def warn(message, []) do
-    message = [to_chardata(message), ?\n]
-    :elixir_errors.log_and_print_warning(0, nil, message, message)
-  end
-
-  def warn(message, %Macro.Env{} = env) do
-    warn(message, Macro.Env.stacktrace(env))
-  end
-
-  def warn(message, [{_, _} | _] = keyword) do
-    if file = keyword[:file] do
-      warn(
-        message,
-        %{
-          __ENV__
-          | module: keyword[:module],
-            function: keyword[:function],
-            line: keyword[:line],
-            file: file
-        }
-      )
-    else
-      warn(message, [])
-    end
+    :elixir_errors.bare_warn(nil, nil, [to_chardata(message), ?\n])
   end
 
   def warn(message, [{_, _, _, opts} | _] = stacktrace) do
-    message = to_chardata(message)
     formatted_trace = Enum.map_join(stacktrace, "\n  ", &Exception.format_stacktrace_entry(&1))
+    message = [to_chardata(message), ?\n, "  ", formatted_trace, ?\n]
     line = opts[:line]
     file = opts[:file]
-
-    :elixir_errors.log_and_print_warning(
-      line || 0,
-      file && List.to_string(file),
-      message,
-      [message, ?\n, "  ", formatted_trace, ?\n]
-    )
-  end
-
-  @doc false
-  def warn_once(key, message, stacktrace_drop_levels) do
-    {:current_stacktrace, stacktrace} = Process.info(self(), :current_stacktrace)
-    stacktrace = Enum.drop(stacktrace, stacktrace_drop_levels)
-
-    if :elixir_config.warn(key, stacktrace) do
-      warn(message, stacktrace)
-    else
-      :ok
-    end
+    :elixir_errors.bare_warn(line, file && List.to_string(file), message)
   end
 
   @doc """
@@ -382,14 +230,9 @@ defmodule IO do
 
   It returns `:ok` if it succeeds.
 
-  Do not call this function at the tail of another function. Due to tail
-  call optimization, a stacktrace entry would not be added and the
-  stacktrace would be incorrectly trimmed. Therefore make sure at least
-  one expression (or an atom such as `:ok`) follows the `IO.warn/1` call.
-
   ## Examples
 
-      IO.warn("variable bar is unused")
+      IO.warn "variable bar is unused"
       #=> warning: variable bar is unused
       #=>   (iex) evaluator.ex:108: IEx.Evaluator.eval/4
 
@@ -420,7 +263,7 @@ defmodule IO do
 
   ## Examples
 
-      IO.inspect(<<0, 1, 2>>, width: 40)
+      IO.inspect <<0, 1, 2>>, width: 40
 
   Prints:
 
@@ -428,7 +271,7 @@ defmodule IO do
 
   We can use the `:label` option to decorate the output:
 
-      IO.inspect(1..100, label: "a wonderful range")
+      IO.inspect 1..100, label: "a wonderful range"
 
   Prints:
 
@@ -440,7 +283,7 @@ defmodule IO do
       |> IO.inspect(label: "before")
       |> Enum.map(&(&1 * 2))
       |> IO.inspect(label: "after")
-      |> Enum.sum()
+      |> Enum.sum
 
   Prints:
 
@@ -459,9 +302,9 @@ defmodule IO do
   See `inspect/2` for a full list of options.
   """
   @spec inspect(device, item, keyword) :: item when item: var
-  def inspect(device, item, opts) when is_device(device) and is_list(opts) do
+  def inspect(device, item, opts) when is_list(opts) do
     label = if label = opts[:label], do: [to_chardata(label), ": "], else: []
-    opts = Inspect.Opts.new(opts)
+    opts = struct(Inspect.Opts, opts)
     doc = Inspect.Algebra.group(Inspect.Algebra.to_doc(item, opts))
     chardata = Inspect.Algebra.format(doc, opts.width)
     puts(device, [label, chardata])
@@ -472,21 +315,15 @@ defmodule IO do
   Gets a number of bytes from IO device `:stdio`.
 
   If `:stdio` is a Unicode device, `count` implies
-  the number of Unicode code points to be retrieved.
+  the number of Unicode codepoints to be retrieved.
   Otherwise, `count` is the number of raw bytes to be retrieved.
 
   See `IO.getn/3` for a description of return values.
-  """
-  @spec getn(
-          device | chardata | String.Chars.t(),
-          pos_integer | :eof | chardata | String.Chars.t()
-        ) ::
-          chardata | nodata
-  def getn(prompt, count \\ 1)
 
-  def getn(prompt, :eof) do
-    getn(:stdio, prompt, :eof)
-  end
+  """
+  @spec getn(chardata | String.Chars.t(), pos_integer) :: chardata | nodata
+  @spec getn(device, chardata | String.Chars.t()) :: chardata | nodata
+  def getn(prompt, count \\ 1)
 
   def getn(prompt, count) when is_integer(count) and count > 0 do
     getn(:stdio, prompt, count)
@@ -500,7 +337,7 @@ defmodule IO do
   Gets a number of bytes from the IO `device`.
 
   If the IO `device` is a Unicode device, `count` implies
-  the number of Unicode code points to be retrieved.
+  the number of Unicode codepoints to be retrieved.
   Otherwise, `count` is the number of raw bytes to be retrieved.
 
   It returns:
@@ -514,27 +351,11 @@ defmodule IO do
       NFS volume
 
   """
-  @spec getn(device, chardata | String.Chars.t(), pos_integer | :eof) :: chardata | nodata
-  def getn(device, prompt, :eof) do
-    getn_eof(map_dev(device), to_chardata(prompt), [])
-  end
-
+  @spec getn(device, chardata | String.Chars.t(), pos_integer) :: chardata | nodata
   def getn(device, prompt, count) when is_integer(count) and count > 0 do
     :io.get_chars(map_dev(device), to_chardata(prompt), count)
   end
 
-  defp getn_eof(device, prompt, acc) do
-    case :io.get_line(device, prompt) do
-      line when is_binary(line) or is_list(line) -> getn_eof(device, '', [line | acc])
-      :eof -> wrap_eof(:lists.reverse(acc))
-      other -> other
-    end
-  end
-
-  defp wrap_eof([h | _] = acc) when is_binary(h), do: IO.iodata_to_binary(acc)
-  defp wrap_eof([h | _] = acc) when is_list(h), do: :lists.flatten(acc)
-  defp wrap_eof([]), do: :eof
-
   @doc ~S"""
   Reads a line from the IO `device`.
 
@@ -553,7 +374,7 @@ defmodule IO do
 
   To display "What is your name?" as a prompt and await user input:
 
-      IO.gets("What is your name?\n")
+      IO.gets "What is your name?\n"
 
   """
   @spec gets(device, chardata | String.Chars.t()) :: chardata | nodata
@@ -561,17 +382,6 @@ defmodule IO do
     :io.get_line(map_dev(device), to_chardata(prompt))
   end
 
-  @doc """
-  Returns a line-based `IO.Stream` on `:stdio`.
-
-  This is equivalent to:
-
-      IO.stream(:stdio, :line)
-
-  """
-  @doc since: "1.12.0"
-  def stream, do: stream(:stdio, :line)
-
   @doc """
   Converts the IO `device` into an `IO.Stream`.
 
@@ -588,35 +398,21 @@ defmodule IO do
   Note that an IO stream has side effects and every time
   you go over the stream you may get different results.
 
-  `stream/0` has been introduced in Elixir v1.12.0,
-  while `stream/2` has been available since v1.0.0.
-
   ## Examples
 
   Here is an example on how we mimic an echo server
   from the command line:
 
-      Enum.each(IO.stream(:stdio, :line), &IO.write(&1))
+      Enum.each IO.stream(:stdio, :line), &IO.write(&1)
 
   """
   @spec stream(device, :line | pos_integer) :: Enumerable.t()
-  def stream(device \\ :stdio, line_or_codepoints)
+  def stream(device, line_or_codepoints)
       when line_or_codepoints == :line
       when is_integer(line_or_codepoints) and line_or_codepoints > 0 do
     IO.Stream.__build__(map_dev(device), false, line_or_codepoints)
   end
 
-  @doc """
-  Returns a raw, line-based `IO.Stream` on `:stdio`. The operation is Unicode unsafe.
-
-  This is equivalent to:
-
-      IO.binstream(:stdio, :line)
-
-  """
-  @doc since: "1.12.0"
-  def binstream, do: binstream(:stdio, :line)
-
   @doc """
   Converts the IO `device` into an `IO.Stream`. The operation is Unicode unsafe.
 
@@ -625,7 +421,8 @@ defmodule IO do
   and write.
 
   The `device` is iterated by the given number of bytes or line by line if
-  `:line` is given. This reads from the IO device as a raw binary.
+  `:line` is given.
+  This reads from the IO device as a raw binary.
 
   Note that an IO stream has side effects and every time
   you go over the stream you may get different results.
@@ -633,21 +430,17 @@ defmodule IO do
   Finally, do not use this function on IO devices in Unicode
   mode as it will return the wrong result.
 
-  `binstream/0` has been introduced in Elixir v1.12.0,
-  while `binstream/2` has been available since v1.0.0.
   """
   @spec binstream(device, :line | pos_integer) :: Enumerable.t()
-  def binstream(device \\ :stdio, line_or_bytes)
+  def binstream(device, line_or_bytes)
       when line_or_bytes == :line
       when is_integer(line_or_bytes) and line_or_bytes > 0 do
     IO.Stream.__build__(map_dev(device), true, line_or_bytes)
   end
 
   @doc """
-  Converts chardata into a string.
-
-  For more information about chardata, see the ["Chardata"](#module-chardata)
-  section in the module documentation.
+  Converts chardata (a list of integers representing codepoints,
+  lists and strings) into a string.
 
   In case the conversion fails, it raises an `UnicodeConversionError`.
   If a string is given, it returns the string itself.
@@ -664,9 +457,7 @@ defmodule IO do
       "string"
 
   """
-  @spec chardata_to_string(chardata) :: String.t()
-  def chardata_to_string(chardata)
-
+  @spec chardata_to_string(chardata) :: String.t() | no_return
   def chardata_to_string(string) when is_binary(string) do
     string
   end
@@ -676,16 +467,14 @@ defmodule IO do
   end
 
   @doc """
-  Converts IO data into a binary
-
+  Converts iodata (a list of integers representing bytes, lists
+  and binaries) into a binary.
   The operation is Unicode unsafe.
 
-  Note that this function treats integers in the given IO data as
-  raw bytes and does not perform any kind of encoding conversion.
-  If you want to convert from a charlist to a UTF-8-encoded string,
-  use `chardata_to_string/1` instead. For more information about
-  IO data and chardata, see the ["IO data"](#module-io-data) section in the
-  module documentation.
+  Notice that this function treats lists of integers as raw bytes
+  and does not perform any kind of encoding conversion. If you want
+  to convert from a charlist to a string (UTF-8 encoded), please
+  use `chardata_to_string/1` instead.
 
   If this function receives a binary, the same binary is returned.
 
@@ -705,15 +494,12 @@ defmodule IO do
 
   """
   @spec iodata_to_binary(iodata) :: binary
-  def iodata_to_binary(iodata) do
-    :erlang.iolist_to_binary(iodata)
+  def iodata_to_binary(item) do
+    :erlang.iolist_to_binary(item)
   end
 
   @doc """
-  Returns the size of an IO data.
-
-  For more information about IO data, see the ["IO data"](#module-io-data)
-  section in the module documentation.
+  Returns the size of an iodata.
 
   Inlined by the compiler.
 
@@ -724,8 +510,8 @@ defmodule IO do
 
   """
   @spec iodata_length(iodata) :: non_neg_integer
-  def iodata_length(iodata) do
-    :erlang.iolist_size(iodata)
+  def iodata_length(item) do
+    :erlang.iolist_size(item)
   end
 
   @doc false

lib/elixir/lib/io/ansi.ex

@@ -3,7 +3,6 @@ defmodule IO.ANSI.Sequence do
 
   defmacro defsequence(name, code, terminator \\ "m") do
     quote bind_quoted: [name: name, code: code, terminator: terminator] do
-      @spec unquote(name)() :: String.t()
       def unquote(name)() do
         "\e[#{unquote(code)}#{unquote(terminator)}"
       end
@@ -22,31 +21,6 @@ defmodule IO.ANSI do
   [ANSI escape sequences](https://en.wikipedia.org/wiki/ANSI_escape_code)
   are characters embedded in text used to control formatting, color, and
   other output options on video text terminals.
-
-  ANSI escapes are typically enabled on all Unix terminals. They are also
-  available on Windows consoles from Windows 10, although it must be
-  explicitly enabled for the current user in the registry by running the
-  following command:
-
-      reg add HKCU\\Console /v VirtualTerminalLevel /t REG_DWORD /d 1
-
-  After running the command above, you must restart your current console.
-
-  ## Examples
-
-  Because the ANSI escape sequences are embedded in text, the normal usage of
-  these functions is to concatenate their output with text.
-
-      formatted_text = IO.ANSI.blue_background() <> "Example" <> IO.ANSI.reset()
-      IO.puts(formatted_text)
-
-  A higher level and more convenient API is also available via `IO.ANSI.format/1`,
-  where you use atoms to represent each ANSI escape sequence and by default
-  checks if ANSI is enabled:
-
-      IO.puts(IO.ANSI.format([:blue_background, "Example"]))
-
-  In case ANSI is disabled, the ANSI escape sequences are simply discarded.
   """
 
   import IO.ANSI.Sequence
@@ -69,34 +43,6 @@ defmodule IO.ANSI do
     Application.get_env(:elixir, :ansi_enabled, false)
   end
 
-  @doc """
-  Syntax colors to be used by `Inspect`.
-
-  Those colors are used throughout Elixir's standard library,
-  such as `dbg/2` and `IEx`.
-
-  The colors can be changed by setting the `:ansi_syntax_colors`
-  in the `:elixir` application configuration. Configuration for
-  most built-in data types are supported: `:atom`, `:binary`,
-  `:boolean`, `:charlist`, `:list`, `:map`, `:nil`, `:number`,
-  `:string`, and `:tuple`. The default is:
-
-      [
-        atom: :cyan
-        boolean: :magenta,
-        charlist: :yellow,
-        nil: :magenta,
-        number: :yellow,
-        string: :green
-      ]
-
-  """
-  @doc since: "1.14.0"
-  @spec syntax_colors :: Keyword.t(ansidata)
-  def syntax_colors do
-    Application.fetch_env!(:elixir, :ansi_syntax_colors)
-  end
-
   @doc "Sets foreground color."
   @spec color(0..255) :: String.t()
   def color(code) when code in 0..255, do: "\e[38;5;#{code}m"
@@ -271,7 +217,7 @@ defmodule IO.ANSI do
   performed. If you don't want this behaviour, use `format_fragment/2`.
 
   An optional boolean parameter can be passed to enable or disable
-  emitting actual ANSI codes. When `false`, no ANSI codes will be emitted.
+  emitting actual ANSI codes. When `false`, no ANSI codes will emitted.
   By default checks if ANSI is enabled using the `enabled?/0` function.
 
   ## Examples
@@ -280,9 +226,8 @@ defmodule IO.ANSI do
       [[[[[[], "Hello, "] | "\e[31m"] | "\e[1m"], "world!"] | "\e[0m"]
 
   """
-  @spec format(ansidata, boolean) :: IO.chardata()
-  def format(ansidata, emit? \\ enabled?()) when is_boolean(emit?) do
-    do_format(ansidata, [], [], emit?, :maybe)
+  def format(chardata, emit? \\ enabled?()) when is_boolean(emit?) do
+    do_format(chardata, [], [], emit?, :maybe)
   end
 
   @doc ~S"""
@@ -292,7 +237,7 @@ defmodule IO.ANSI do
   The named sequences are represented by atoms.
 
   An optional boolean parameter can be passed to enable or disable
-  emitting actual ANSI codes. When `false`, no ANSI codes will be emitted.
+  emitting actual ANSI codes. When `false`, no ANSI codes will emitted.
   By default checks if ANSI is enabled using the `enabled?/0` function.
 
   ## Examples
@@ -301,9 +246,8 @@ defmodule IO.ANSI do
       [[[[[[] | "\e[1m"], 87], 111], 114], 100]
 
   """
-  @spec format_fragment(ansidata, boolean) :: IO.chardata()
-  def format_fragment(ansidata, emit? \\ enabled?()) when is_boolean(emit?) do
-    do_format(ansidata, [], [], emit?, false)
+  def format_fragment(chardata, emit? \\ enabled?()) when is_boolean(emit?) do
+    do_format(chardata, [], [], emit?, false)
   end
 
   defp do_format([term | rest], rem, acc, emit?, append_reset) do

lib/elixir/lib/io/ansi/docs.ex

@@ -1,8 +1,6 @@
 defmodule IO.ANSI.Docs do
   @moduledoc false
 
-  @bullet_text_unicode "• "
-  @bullet_text_ascii "* "
   @bullets [?*, ?-, ?+]
   @spaces [" ", "\n", "\t"]
 
@@ -16,7 +14,6 @@ defmodule IO.ANSI.Docs do
     * `:doc_code`          - code blocks (cyan)
     * `:doc_headings`      - h1, h2, h3, h4, h5, h6 headings (yellow)
     * `:doc_metadata`      - documentation metadata keys (yellow)
-    * `:doc_quote`         - leading quote character `> ` (light black)
     * `:doc_inline_code`   - inline code (cyan)
     * `:doc_table_heading` - the style for table headings
     * `:doc_title`         - top level heading (reverse, yellow)
@@ -34,7 +31,6 @@ defmodule IO.ANSI.Docs do
       doc_code: [:cyan],
       doc_headings: [:yellow],
       doc_metadata: [:yellow],
-      doc_quote: [:light_black],
       doc_inline_code: [:cyan],
       doc_table_heading: [:reverse],
       doc_title: [:reverse, :yellow],
@@ -48,24 +44,19 @@ defmodule IO.ANSI.Docs do
 
   See `default_options/0` for docs on the supported options.
   """
-  @spec print_headings([String.t()], keyword) :: :ok
-  def print_headings(headings, options \\ []) do
+  @spec print_heading(String.t(), keyword) :: :ok
+  def print_heading(heading, options \\ []) do
+    IO.puts(IO.ANSI.reset())
     options = Keyword.merge(default_options(), options)
-    newline_after_block(options)
     width = options[:width]
-
-    for heading <- headings do
-      padding = div(width + String.length(heading), 2)
-      heading = String.pad_leading(heading, padding)
-      heading = if options[:enabled], do: String.pad_trailing(heading, width), else: heading
-      write(:doc_title, heading, options)
-    end
-
-    newline_after_block(options)
+    padding = div(width + String.length(heading), 2)
+    heading = heading |> String.pad_leading(padding) |> String.pad_trailing(width)
+    write(:doc_title, heading, options)
+    newline_after_block()
   end
 
   @doc """
-  Prints documentation metadata (only `delegate_to`, `deprecated`, `guard`, and `since` for now).
+  Prints documentation metadata (only `since` and `deprecated` for now).
 
   See `default_options/0` for docs on the supported options.
   """
@@ -75,21 +66,14 @@ defmodule IO.ANSI.Docs do
     print_each_metadata(metadata, options) && IO.write("\n")
   end
 
-  @metadata_filter [:deprecated, :guard, :since]
+  @metadata_filter [:deprecated, :since]
 
   defp print_each_metadata(metadata, options) do
     Enum.reduce(metadata, false, fn
       {key, value}, _printed when is_binary(value) and key in @metadata_filter ->
         label = metadata_label(key, options)
         indent = String.duplicate(" ", length_without_escape(label, 0) + 1)
-        write_with_wrap([label | String.split(value, @spaces)], options[:width], indent, true, "")
-
-      {key, value}, _printed when is_boolean(value) and key in @metadata_filter ->
-        IO.puts([metadata_label(key, options), ?\s, to_string(value)])
-
-      {:delegate_to, {m, f, a}}, _printed ->
-        label = metadata_label(:delegate_to, options)
-        IO.puts([label, ?\s, Exception.format_mfa(m, f, a)])
+        write_with_wrap([label | String.split(value, @spaces)], options[:width], indent, true)
 
       _metadata, printed ->
         printed
@@ -97,214 +81,21 @@ defmodule IO.ANSI.Docs do
   end
 
   defp metadata_label(key, options) do
-    "#{color(:doc_metadata, options)}#{key}:#{maybe_reset(options)}"
+    if options[:enabled] do
+      "#{color(:doc_metadata, options)}#{key}:#{IO.ANSI.reset()}"
+    else
+      "#{key}:"
+    end
   end
 
   @doc """
-  Prints the documentation body `doc` according to `format`.
+  Prints the documentation body.
 
-  It takes a set of `options` defined in `default_options/0`.
+  In addition to the printing string, takes a set of options
+  defined in `default_options/0`.
   """
-  @spec print(term(), String.t(), keyword) :: :ok
-  def print(doc, format, options \\ [])
-
-  def print(doc, "text/markdown", options) when is_binary(doc) and is_list(options) do
-    print_markdown(doc, options)
-  end
-
-  def print(doc, "application/erlang+html", options) when is_list(options) do
-    print_erlang_html(doc, options)
-  end
-
-  def print(_doc, format, options) when is_binary(format) and is_list(options) do
-    IO.puts("\nUnknown documentation format #{inspect(format)}\n")
-  end
-
-  ## Erlang+html
-
-  def print_erlang_html(doc, options) do
-    options = Keyword.merge(default_options(), options)
-    IO.write(traverse_erlang_html(doc, "", options))
-  end
-
-  defp traverse_erlang_html(text, _indent, _options) when is_binary(text) do
-    text
-  end
-
-  defp traverse_erlang_html(nodes, indent, options) when is_list(nodes) do
-    for node <- nodes do
-      traverse_erlang_html(node, indent, options)
-    end
-  end
-
-  defp traverse_erlang_html({:div, [class: class] ++ _, entries}, indent, options) do
-    prefix = indent <> quote_prefix(options)
-
-    content =
-      entries
-      |> traverse_erlang_html(indent, options)
-      |> IO.iodata_to_binary()
-      |> String.trim_trailing()
-
-    [
-      prefix,
-      class |> to_string() |> String.upcase(),
-      "\n#{prefix}\n#{prefix}" | String.replace(content, "\n", "\n#{prefix}")
-    ]
-    |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:p, _, entries}, indent, options) do
-    [indent | handle_erlang_html_text(entries, indent, options)]
-  end
-
-  defp traverse_erlang_html({:h1, _, entries}, indent, options) do
-    entries |> traverse_erlang_html(indent, options) |> heading(1, options) |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:h2, _, entries}, indent, options) do
-    entries |> traverse_erlang_html(indent, options) |> heading(2, options) |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:h3, _, entries}, indent, options) do
-    entries |> traverse_erlang_html(indent, options) |> heading(3, options) |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:h4, _, entries}, indent, options) do
-    entries |> traverse_erlang_html(indent, options) |> heading(4, options) |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:h5, _, entries}, indent, options) do
-    entries |> traverse_erlang_html(indent, options) |> heading(5, options) |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:h6, _, entries}, indent, options) do
-    entries |> traverse_erlang_html(indent, options) |> heading(6, options) |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:br, _, []}, _indent, _options) do
-    []
-  end
-
-  defp traverse_erlang_html({:i, _, entries}, indent, options) do
-    inline_text("_", traverse_erlang_html(entries, indent, options), options)
-  end
-
-  defp traverse_erlang_html({:em, _, entries}, indent, options) do
-    inline_text("*", traverse_erlang_html(entries, indent, options), options)
-  end
-
-  defp traverse_erlang_html({tag, _, entries}, indent, options) when tag in [:strong, :b] do
-    inline_text("**", traverse_erlang_html(entries, indent, options), options)
-  end
-
-  defp traverse_erlang_html({:code, _, entries}, indent, options) do
-    inline_text("`", traverse_erlang_html(entries, indent, options), options)
-  end
-
-  defp traverse_erlang_html({:pre, _, [{:code, _, entries}]}, indent, options) do
-    string =
-      entries
-      |> traverse_erlang_html(indent, options)
-      |> IO.iodata_to_binary()
-
-    ["#{indent}    ", String.replace(string, "\n", "\n#{indent}    ")] |> newline_cons()
-  end
-
-  defp traverse_erlang_html({:a, attributes, entries}, indent, options) do
-    if href = attributes[:href] do
-      [traverse_erlang_html(entries, indent, options), ?\s, ?(, href, ?)]
-    else
-      traverse_erlang_html(entries, indent, options)
-    end
-  end
-
-  defp traverse_erlang_html({:dl, _, entries}, indent, options) do
-    traverse_erlang_html(entries, indent, options)
-  end
-
-  defp traverse_erlang_html({:dt, _, entries}, indent, options) do
-    [
-      "#{indent}  ",
-      bullet_text(options) | handle_erlang_html_text(entries, indent <> "    ", options)
-    ]
-  end
-
-  defp traverse_erlang_html({:dd, _, entries}, indent, options) do
-    ["#{indent}    " | handle_erlang_html_text(entries, indent <> "    ", options)]
-  end
-
-  defp traverse_erlang_html({:ul, attributes, entries}, indent, options) do
-    if attributes[:class] == "types" do
-      types =
-        for {:li, _, lines} <- entries,
-            line <- lines,
-            do: ["#{indent}    ", traverse_erlang_html(line, indent <> "    ", options), ?\n]
-
-      if types != [] do
-        ["#{indent}Typespecs:\n\n", types, ?\n]
-      else
-        []
-      end
-    else
-      for {:li, _, lines} <- entries do
-        [
-          "#{indent}  ",
-          bullet_text(options) | handle_erlang_html_text(lines, indent <> "    ", options)
-        ]
-      end
-    end
-  end
-
-  defp traverse_erlang_html({:ol, _, entries}, indent, options) do
-    for {{:li, _, lines}, i} <- Enum.with_index(entries, 1) do
-      [
-        "#{indent}  ",
-        Integer.to_string(i),
-        ". " | handle_erlang_html_text(lines, indent <> "     ", options)
-      ]
-    end
-  end
-
-  defp traverse_erlang_html({tag, _, entries}, indent, options) do
-    [
-      indent <> "<#{tag}>\n",
-      traverse_erlang_html(entries, indent <> "    ", options)
-      |> IO.iodata_to_binary()
-      |> String.trim_trailing(),
-      "\n" <> indent <> "</#{tag}>"
-    ]
-    |> newline_cons()
-  end
-
-  defp newline_cons(text) do
-    [text | "\n\n"]
-  end
-
-  defp handle_erlang_html_text(entries, indent, options) do
-    if Enum.all?(entries, &inline_html?/1) do
-      entries
-      |> traverse_erlang_html(indent, options)
-      |> IO.iodata_to_binary()
-      |> String.split(@spaces)
-      |> wrap_text(options[:width], indent, true, "", [])
-      |> tl()
-      |> newline_cons()
-    else
-      entries
-      |> traverse_erlang_html(indent, options)
-      |> IO.iodata_to_binary()
-      |> String.trim_leading()
-    end
-  end
-
-  defp inline_html?(binary) when is_binary(binary), do: true
-  defp inline_html?({tag, _, _}) when tag in [:a, :code, :em, :i, :strong, :b, :br], do: true
-  defp inline_html?(_), do: false
-
-  ## Markdown
-
-  def print_markdown(doc, options) do
+  @spec print(String.t(), keyword) :: :ok
+  def print(doc, options \\ []) do
     options = Keyword.merge(default_options(), options)
 
     doc
@@ -341,11 +132,6 @@ defmodule IO.ANSI.Docs do
     write_heading(heading, rest, text, indent, options)
   end
 
-  defp process([">" <> line | rest], text, indent, options) do
-    write_text(text, indent, options)
-    process_quote(rest, [line], indent, options)
-  end
-
   defp process(["" | rest], text, indent, options) do
     write_text(text, indent, options)
     process(rest, [], indent, options)
@@ -381,61 +167,22 @@ defmodule IO.ANSI.Docs do
     end
   end
 
-  ### Headings
+  ## Headings
 
   defp write_heading(heading, rest, text, indent, options) do
     write_text(text, indent, options)
     write(:doc_headings, heading, options)
-    newline_after_block(options)
+    newline_after_block()
     process(rest, [], "", options)
   end
 
-  ### Quotes
-
-  defp process_quote([], lines, indent, options) do
-    write_quote(lines, indent, options, false)
-  end
-
-  defp process_quote([">", ">" <> line | rest], lines, indent, options) do
-    write_quote(lines, indent, options, true)
-    write_empty_quote_line(options)
-    process_quote(rest, [line], indent, options)
-  end
-
-  defp process_quote([">" <> line | rest], lines, indent, options) do
-    process_quote(rest, [line | lines], indent, options)
-  end
-
-  defp process_quote(rest, lines, indent, options) do
-    write_quote(lines, indent, options, false)
-    process(rest, [], indent, options)
-  end
-
-  defp write_quote(lines, indent, options, no_wrap) do
-    lines
-    |> Enum.map(&String.trim/1)
-    |> Enum.reverse()
-    |> write_lines(
-      indent,
-      options,
-      no_wrap,
-      quote_prefix(options)
-    )
-  end
-
-  defp write_empty_quote_line(options) do
-    options
-    |> quote_prefix()
-    |> IO.puts()
-  end
-
-  ### Lists
+  ## Lists
 
   defp process_rest(stripped, rest, count, text, indent, options) do
     case stripped do
       <<bullet, ?\s, item::binary>> when bullet in @bullets ->
         write_text(text, indent, options)
-        process_list(bullet_text(options), item, rest, count, indent, options)
+        process_list("• ", item, rest, count, indent, options)
 
       <<d1, ?., ?\s, item::binary>> when d1 in ?0..?9 ->
         write_text(text, indent, options)
@@ -455,12 +202,10 @@ defmodule IO.ANSI.Docs do
     entry = if indent == "", do: "  " <> entry, else: entry
     new_indent = indent <> String.duplicate(" ", String.length(entry))
 
-    {contents, rest, done} =
-      process_list_next(rest, count, byte_size(new_indent) - byte_size(indent), [])
-
+    {contents, rest, done} = process_list_next(rest, count, byte_size(new_indent), [])
     process(contents, [indent <> entry <> line, :no_wrap], new_indent, options)
 
-    if done, do: newline_after_block(options)
+    if done, do: newline_after_block()
     process(rest, [], indent, options)
   end
 
@@ -501,7 +246,7 @@ defmodule IO.ANSI.Docs do
     end
   end
 
-  ### Text
+  ## Text
 
   defp write_text(text, indent, options) do
     case Enum.reverse(text) do
@@ -515,26 +260,17 @@ defmodule IO.ANSI.Docs do
   end
 
   defp write_text(lines, indent, options, no_wrap) do
-    write_lines(lines, indent, options, no_wrap, "")
-  end
-
-  defp write_lines(lines, indent, options, no_wrap, prefix) do
     lines
     |> Enum.join(" ")
-    |> format_text(options)
-    |> String.split(@spaces)
-    |> write_with_wrap(options[:width] - byte_size(indent), indent, no_wrap, prefix)
-
-    unless no_wrap, do: newline_after_block(options)
-  end
-
-  defp format_text(text, options) do
-    text
-    |> handle_links()
+    |> handle_links
     |> handle_inline(options)
+    |> String.split(@spaces)
+    |> write_with_wrap(options[:width] - byte_size(indent), indent, no_wrap)
+
+    unless no_wrap, do: newline_after_block()
   end
 
-  ### Code blocks
+  ## Code blocks
 
   defp process_code([], code, indent, options) do
     write_code(code, indent, options)
@@ -573,15 +309,15 @@ defmodule IO.ANSI.Docs do
 
   defp write_code(code, indent, options) do
     write(:doc_code, "#{indent}    #{Enum.join(Enum.reverse(code), "\n#{indent}    ")}", options)
-    newline_after_block(options)
+    newline_after_block()
   end
 
-  ### Tables
+  ## Tables
 
   defp process_table(lines, indent, options) do
     {table, rest} = Enum.split_while(lines, &table_line?/1)
     table_lines(table, options)
-    newline_after_block(options)
+    newline_after_block()
     process(rest, [], indent, options)
   end
 
@@ -605,17 +341,17 @@ defmodule IO.ANSI.Docs do
 
   defp split_into_columns(line, options) do
     line
-    |> String.trim(" ")
     |> String.trim("|")
-    |> String.split(~r{(?<!\\)\|})
+    |> String.trim()
+    |> String.split(" | ")
     |> Enum.map(&render_column(&1, options))
   end
 
   defp render_column(col, options) do
     col =
       col
-      |> String.trim()
       |> String.replace("\\\|", "|")
+      |> String.trim()
       |> handle_links
       |> handle_inline(options)
 
@@ -707,7 +443,7 @@ defmodule IO.ANSI.Docs do
   end
 
   defp table_line?(line) do
-    line =~ ~r/[:\ -]\|[:\ -]/
+    line =~ " | "
   end
 
   ## Helpers
@@ -724,30 +460,17 @@ defmodule IO.ANSI.Docs do
   defp strip_spaces(rest, acc, _max), do: {rest, acc}
 
   defp write(style, string, options) do
-    IO.puts([color(style, options), string, maybe_reset(options)])
+    IO.puts([color(style, options), string, IO.ANSI.reset()])
   end
 
-  defp write_with_wrap([], _available, _indent, _first, _prefix) do
+  defp write_with_wrap([], _available, _indent, _first) do
     :ok
   end
 
-  defp write_with_wrap(words, available, indent, first, prefix) do
-    words
-    |> wrap_text(available, indent, first, prefix, [])
-    |> tl()
-    |> IO.puts()
-  end
-
-  defp wrap_text([], _available, _indent, _first, _prefix, wrapped_lines) do
-    Enum.reverse(wrapped_lines)
-  end
-
-  defp wrap_text(words, available, indent, first, prefix, wrapped_lines) do
-    prefix_length = length_without_escape(prefix, 0)
-    {words, rest} = take_words(words, available - prefix_length, [])
-    line = [if(first, do: "", else: indent), prefix, Enum.join(words, " ")]
-
-    wrap_text(rest, available, indent, false, prefix, [line, ?\n | wrapped_lines])
+  defp write_with_wrap(words, available, indent, first) do
+    {words, rest} = take_words(words, available, [])
+    IO.puts(if(first, do: "", else: indent) <> Enum.join(words, " "))
+    write_with_wrap(rest, available, indent, false)
   end
 
   defp take_words([word | words], available, acc) do
@@ -794,22 +517,24 @@ defmodule IO.ANSI.Docs do
   end
 
   defp escape_underlines_in_link(text) do
-    # Regular expression adapted from https://tools.ietf.org/html/rfc3986#appendix-B
-    Regex.replace(~r{[a-z][a-z0-9\+\-\.]*://\S*}i, text, &String.replace(&1, "_", "\\_"))
+    ~r{https?\S*}
+    |> Regex.recompile!()
+    |> Regex.replace(text, &String.replace(&1, "_", "\\_"))
   end
 
   defp remove_square_brackets_in_link(text) do
-    Regex.replace(~r{\[([^\]]*?)\]\((.*?)\)}, text, "\\1 (\\2)")
+    ~r{\[(.*?)\]\((.*?)\)}
+    |> Regex.recompile!()
+    |> Regex.replace(text, "\\1 (\\2)")
   end
 
-  # We have four entries: **, __, *, _ and `.
+  # We have four entries: **, *, _ and `.
   #
-  # The first four behave the same while the last one is simpler
-  # when it comes to delimiters as it ignores spaces and escape
-  # characters. But, since the first two has two characters,
-  # we need to handle 3 cases:
+  # The first three behave the same while the last one is simpler
+  # when it comes to delimiters. But, since the first has two
+  # characters, we need to handle 3 cases:
   #
-  # 1. __ and **
+  # 1. **
   # 2. _ and *
   # 3. `
   #
@@ -821,10 +546,10 @@ defmodule IO.ANSI.Docs do
   @delimiters [?\s, ?', ?", ?!, ?@, ?#, ?$, ?%, ?^, ?&] ++
                 [?-, ?+, ?(, ?), ?[, ?], ?{, ?}, ?<, ?>, ?.]
 
-  ### Inline start
+  # Inline start
 
-  defp handle_inline(<<mark, mark, rest::binary>>, options) when mark in @single do
-    handle_inline(rest, [mark | mark], [<<mark, mark>>], [], options)
+  defp handle_inline(<<?*, ?*, rest::binary>>, options) do
+    handle_inline(rest, ?d, ["**"], [], options)
   end
 
   defp handle_inline(<<mark, rest::binary>>, options) when mark in @single do
@@ -835,12 +560,11 @@ defmodule IO.ANSI.Docs do
     handle_inline(rest, nil, [], [], options)
   end
 
-  ### Inline delimiters
+  # Inline delimiters
 
-  defp handle_inline(<<delimiter, mark, mark, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" and delimiter in @delimiters and mark in @single do
-    acc = [delimiter, Enum.reverse(buffer) | acc]
-    handle_inline(rest, [mark | mark], [<<mark, mark>>], acc, options)
+  defp handle_inline(<<delimiter, ?*, ?*, rest::binary>>, nil, buffer, acc, options)
+       when rest != "" and delimiter in @delimiters do
+    handle_inline(rest, ?d, ["**"], [delimiter, Enum.reverse(buffer) | acc], options)
   end
 
   defp handle_inline(<<delimiter, mark, rest::binary>>, nil, buffer, acc, options)
@@ -853,12 +577,11 @@ defmodule IO.ANSI.Docs do
     handle_inline(rest, ?`, ["`"], [Enum.reverse(buffer) | acc], options)
   end
 
-  ### Clauses for handling escape
+  # Clauses for handling escape
 
-  defp handle_inline(<<?\\, ?\\, mark, mark, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" and mark in @single do
-    acc = [?\\, Enum.reverse(buffer) | acc]
-    handle_inline(rest, [mark | mark], [<<mark, mark>>], acc, options)
+  defp handle_inline(<<?\\, ?\\, ?*, ?*, rest::binary>>, nil, buffer, acc, options)
+       when rest != "" do
+    handle_inline(rest, ?d, ["**"], [?\\, Enum.reverse(buffer) | acc], options)
   end
 
   defp handle_inline(<<?\\, ?\\, mark, rest::binary>>, nil, buffer, acc, options)
@@ -871,14 +594,15 @@ defmodule IO.ANSI.Docs do
   end
 
   # An escape is not valid inside `
-  defp handle_inline(<<?\\, mark, rest::binary>>, limit, buffer, acc, options) when limit != ?` do
+  defp handle_inline(<<?\\, mark, rest::binary>>, limit, buffer, acc, options)
+       when not (mark == limit and mark == ?`) do
     handle_inline(rest, limit, [mark | buffer], acc, options)
   end
 
-  ### Inline end
+  # Inline end
 
-  defp handle_inline(<<mark, mark, delimiter, rest::binary>>, [mark | mark], buffer, acc, options)
-       when delimiter in @delimiters and mark in @single do
+  defp handle_inline(<<?*, ?*, delimiter, rest::binary>>, ?d, buffer, acc, options)
+       when delimiter in @delimiters do
     inline_buffer = inline_buffer(buffer, options)
     handle_inline(<<delimiter, rest::binary>>, nil, [], [inline_buffer | acc], options)
   end
@@ -889,8 +613,8 @@ defmodule IO.ANSI.Docs do
     handle_inline(<<delimiter, rest::binary>>, nil, [], [inline_buffer | acc], options)
   end
 
-  defp handle_inline(<<mark, mark, rest::binary>>, [mark | mark], buffer, acc, options)
-       when rest == "" and mark in @single do
+  defp handle_inline(<<?*, ?*, rest::binary>>, ?d, buffer, acc, options)
+       when rest == "" do
     handle_inline(<<>>, nil, [], [inline_buffer(buffer, options) | acc], options)
   end
 
@@ -903,7 +627,7 @@ defmodule IO.ANSI.Docs do
     handle_inline(rest, nil, [], [inline_buffer(buffer, options) | acc], options)
   end
 
-  ### Catch all
+  # Catch all
 
   defp handle_inline(<<char, rest::binary>>, mark, buffer, acc, options) do
     handle_inline(rest, mark, [char | buffer], acc, options)
@@ -914,49 +638,23 @@ defmodule IO.ANSI.Docs do
   end
 
   defp inline_buffer(buffer, options) do
-    [mark | t] = Enum.reverse(buffer)
-    inline_text(mark, t, options)
-  end
-
-  ## Helpers
-
-  defp quote_prefix(options), do: "#{color(:doc_quote, options)}> #{maybe_reset(options)}"
-
-  defp heading(text, n, options) do
-    [color(:doc_headings, options), String.duplicate("#", n), " ", text, maybe_reset(options)]
-  end
-
-  defp inline_text(mark, text, options) do
-    if options[:enabled] do
-      [[color_for(mark, options) | text] | IO.ANSI.reset()]
-    else
-      [[mark | text] | mark]
-    end
+    [h | t] = Enum.reverse([IO.ANSI.reset() | buffer])
+    [color_for(h, options) | t]
   end
 
   defp color_for(mark, colors) do
     case mark do
-      "__" -> color(:doc_bold, colors)
-      "**" -> color(:doc_bold, colors)
-      "_" -> color(:doc_underline, colors)
-      "*" -> color(:doc_underline, colors)
       "`" -> color(:doc_inline_code, colors)
+      "_" -> color(:doc_underline, colors)
+      "*" -> color(:doc_bold, colors)
+      "**" -> color(:doc_bold, colors)
     end
   end
 
-  defp bullet_text(options) do
-    if options[:enabled], do: @bullet_text_unicode, else: @bullet_text_ascii
-  end
-
   defp color(style, colors) do
-    IO.ANSI.format_fragment(colors[style], colors[:enabled])
+    color = colors[style]
+    IO.ANSI.format_fragment(color, colors[:enabled])
   end
 
-  defp newline_after_block(options) do
-    IO.puts(maybe_reset(options))
-  end
-
-  defp maybe_reset(options) do
-    if options[:enabled], do: IO.ANSI.reset(), else: ""
-  end
+  defp newline_after_block, do: IO.puts(IO.ANSI.reset())
 end

lib/elixir/lib/io/stream.ex

@@ -26,11 +26,7 @@ defmodule IO.Stream do
 
   defstruct device: nil, raw: true, line_or_bytes: :line
 
-  @type t :: %__MODULE__{
-          device: IO.device(),
-          raw: boolean(),
-          line_or_bytes: :line | non_neg_integer()
-        }
+  @type t :: %__MODULE__{}
 
   @doc false
   def __build__(device, raw, line_or_bytes) do

lib/elixir/lib/kernel/cli.ex

@@ -1,24 +1,18 @@
 defmodule Kernel.CLI do
   @moduledoc false
 
-  @compile {:no_warn_undefined, [Logger, IEx]}
-
   @blank_config %{
     commands: [],
     output: ".",
     compile: [],
-    no_halt: false,
+    halt: true,
     compiler_options: [],
     errors: [],
     pa: [],
     pz: [],
-    verbose_compile: false,
-    profile: nil,
-    pry: false
+    verbose_compile: false
   }
 
-  @standalone_opts ["-h", "--help", "--short-version"]
-
   @doc """
   This is the API invoked by Elixir boot process.
   """
@@ -27,11 +21,6 @@ defmodule Kernel.CLI do
 
     {config, argv} = parse_argv(argv)
     System.argv(argv)
-    System.no_halt(config.no_halt)
-
-    if config.pry do
-      Application.put_env(:elixir, :dbg_callback, {IEx.Pry, :dbg, []})
-    end
 
     fun = fn _ ->
       errors = process_commands(config)
@@ -42,7 +31,7 @@ defmodule Kernel.CLI do
       end
     end
 
-    run(fun)
+    run(fun, config.halt)
   end
 
   @doc """
@@ -53,10 +42,10 @@ defmodule Kernel.CLI do
   This function is used by Elixir's CLI and also
   by escripts generated by Elixir.
   """
-  def run(fun) do
+  def run(fun, halt \\ true) do
     {ok_or_shutdown, status} = exec_fun(fun, {:ok, 0})
 
-    if ok_or_shutdown == :shutdown or not System.no_halt() do
+    if ok_or_shutdown == :shutdown or halt do
       {_, status} = at_exit({ok_or_shutdown, status})
 
       # Ensure Logger messages are flushed before halting
@@ -69,25 +58,19 @@ defmodule Kernel.CLI do
     end
   end
 
-  @doc """
-  Parses the CLI arguments. Made public for testing.
-  """
+  @doc false
   def parse_argv(argv) do
     parse_argv(argv, @blank_config)
   end
 
-  @doc """
-  Process CLI commands. Made public for testing.
-  """
+  @doc false
   def process_commands(config) do
     results = Enum.map(Enum.reverse(config.commands), &process_command(&1, config))
     errors = for {:error, msg} <- results, do: msg
     Enum.reverse(config.errors, errors)
   end
 
-  @doc """
-  Shared helper for error formatting on CLI tools.
-  """
+  @doc false
   def format_error(kind, reason, stacktrace) do
     {blamed, stacktrace} = Exception.blame(kind, reason, stacktrace)
 
@@ -95,7 +78,7 @@ defmodule Kernel.CLI do
       case blamed do
         %FunctionClauseError{} ->
           formatted = Exception.format_banner(kind, reason, stacktrace)
-          padded_blame = pad(FunctionClauseError.blame(blamed, &inspect/1, &blame_match/1))
+          padded_blame = pad(FunctionClauseError.blame(blamed, &inspect/1, &blame_match/2))
           [formatted, padded_blame]
 
         _ ->
@@ -105,15 +88,6 @@ defmodule Kernel.CLI do
     [iodata, ?\n, Exception.format_stacktrace(prune_stacktrace(stacktrace))]
   end
 
-  @doc """
-  Function invoked across nodes for `--rpc-eval`.
-  """
-  def rpc_eval(expr) do
-    wrapper(fn -> Code.eval_string(expr) end)
-  catch
-    kind, reason -> {kind, reason, __STACKTRACE__}
-  end
-
   ## Helpers
 
   defp at_exit(res) do
@@ -183,8 +157,9 @@ defmodule Kernel.CLI do
     IO.write(:stderr, format_error(kind, reason, stacktrace))
   end
 
-  defp blame_match(%{match?: true, node: node}), do: blame_ansi(:normal, "+", node)
-  defp blame_match(%{match?: false, node: node}), do: blame_ansi(:red, "-", node)
+  defp blame_match(%{match?: true, node: node}, _), do: blame_ansi(:normal, "+", node)
+  defp blame_match(%{match?: false, node: node}, _), do: blame_ansi(:red, "-", node)
+  defp blame_match(_, string), do: string
 
   defp blame_ansi(color, no_ansi, node) do
     if IO.ANSI.enabled?() do
@@ -201,9 +176,8 @@ defmodule Kernel.CLI do
   end
 
   @elixir_internals [:elixir, :elixir_aliases, :elixir_expand, :elixir_compiler, :elixir_module] ++
-                      [:elixir_clauses, :elixir_lexical, :elixir_def, :elixir_map, :elixir_locals] ++
-                      [:elixir_erl, :elixir_erl_clauses, :elixir_erl_compiler, :elixir_erl_pass] ++
-                      [Kernel.ErrorHandler, Module.ParallelChecker]
+                      [:elixir_clauses, :elixir_lexical, :elixir_def, :elixir_map] ++
+                      [:elixir_erl, :elixir_erl_clauses, :elixir_erl_pass, Kernel.ErrorHandler]
 
   defp prune_stacktrace([{mod, _, _, _} | t]) when mod in @elixir_internals do
     prune_stacktrace(t)
@@ -223,16 +197,7 @@ defmodule Kernel.CLI do
 
   # Parse shared options
 
-  defp halt_standalone(opt) do
-    IO.puts(:stderr, "#{opt} : Standalone options can't be combined with other options")
-    System.halt(1)
-  end
-
-  defp parse_shared([opt | _], _config) when opt in @standalone_opts do
-    halt_standalone(opt)
-  end
-
-  defp parse_shared([opt | t], _config) when opt in ["-v", "--version"] do
+  defp parse_shared([opt | _t], _config) when opt in ["-v", "--version"] do
     if function_exported?(IEx, :started?, 0) and IEx.started?() do
       IO.puts("IEx " <> System.build_info()[:build])
     else
@@ -240,11 +205,7 @@ defmodule Kernel.CLI do
       IO.puts("Elixir " <> System.build_info()[:build])
     end
 
-    if t != [] do
-      halt_standalone(opt)
-    else
-      System.halt(0)
-    end
+    System.halt(0)
   end
 
   defp parse_shared(["-pa", h | t], config) do
@@ -264,27 +225,13 @@ defmodule Kernel.CLI do
   end
 
   defp parse_shared(["--no-halt" | t], config) do
-    parse_shared(t, %{config | no_halt: true})
+    parse_shared(t, %{config | halt: false})
   end
 
   defp parse_shared(["-e", h | t], config) do
     parse_shared(t, %{config | commands: [{:eval, h} | config.commands]})
   end
 
-  defp parse_shared(["--eval", h | t], config) do
-    parse_shared(t, %{config | commands: [{:eval, h} | config.commands]})
-  end
-
-  defp parse_shared(["--rpc-eval", node, h | t], config) do
-    node = append_hostname(node)
-    parse_shared(t, %{config | commands: [{:rpc_eval, node, h} | config.commands]})
-  end
-
-  defp parse_shared(["--rpc-eval" | _], config) do
-    new_config = %{config | errors: ["--rpc-eval : wrong number of arguments" | config.errors]}
-    {[], new_config}
-  end
-
   defp parse_shared(["-r", h | t], config) do
     parse_shared(t, %{config | commands: [{:require, h} | config.commands]})
   end
@@ -293,15 +240,21 @@ defmodule Kernel.CLI do
     parse_shared(t, %{config | commands: [{:parallel_require, h} | config.commands]})
   end
 
-  defp parse_shared(list, config) do
-    {list, config}
+  @erl_arg_options ["--erl", "--sname", "--name", "--cookie"] ++
+                     ["--logger-otp-reports", "--logger-sasl-reports"]
+
+  @erl_boolean_options ["--detached", "--hidden", "--werl"]
+
+  defp parse_shared([erl, _ | t], config) when erl in @erl_arg_options do
+    parse_shared(t, config)
   end
 
-  defp append_hostname(node) do
-    case :string.find(node, "@") do
-      :nomatch -> node <> :string.find(Atom.to_string(node()), "@")
-      _ -> node
-    end
+  defp parse_shared([erl | t], config) when erl in @erl_boolean_options do
+    parse_shared(t, config)
+  end
+
+  defp parse_shared(list, config) do
+    {list, config}
   end
 
   defp expand_code_path(path) do
@@ -324,7 +277,7 @@ defmodule Kernel.CLI do
   end
 
   defp parse_argv(["+iex" | t], config) do
-    parse_iex(t, %{config | pry: true})
+    parse_iex(t, config)
   end
 
   defp parse_argv(["-S", h | t], config) do
@@ -337,7 +290,7 @@ defmodule Kernel.CLI do
         shared_option?(list, config, &parse_argv(&1, &2))
 
       _ ->
-        if List.keymember?(config.commands, :eval, 0) do
+        if Keyword.has_key?(config.commands, :eval) do
           {config, list}
         else
           {%{config | commands: [{:file, h} | config.commands]}, t}
@@ -382,12 +335,6 @@ defmodule Kernel.CLI do
     parse_compiler(t, %{config | verbose_compile: true})
   end
 
-  # Private compiler options
-
-  defp parse_compiler(["--profile", "time" | t], config) do
-    parse_compiler(t, %{config | profile: :time})
-  end
-
   defp parse_compiler([h | t] = list, config) do
     case h do
       "-" <> _ ->
@@ -409,16 +356,20 @@ defmodule Kernel.CLI do
     {config, t}
   end
 
+  # This clause is here so that Kernel.CLI does not
+  # error out with "unknown option"
+  defp parse_iex(["--dot-iex", _ | t], config) do
+    parse_iex(t, config)
+  end
+
+  defp parse_iex([opt, _ | t], config) when opt in ["--remsh"] do
+    parse_iex(t, config)
+  end
+
   defp parse_iex(["-S", h | t], config) do
     {%{config | commands: [{:script, h} | config.commands]}, t}
   end
 
-  # These clauses are here so that Kernel.CLI does not error out with "unknown option"
-  defp parse_iex(["--dot-iex", _ | t], config), do: parse_iex(t, config)
-  defp parse_iex(["--remsh", _ | t], config), do: parse_iex(t, config)
-
-  defp parse_iex(["--no-pry" | t], config), do: parse_iex(t, %{config | pry: false})
-
   defp parse_iex([h | t] = list, config) do
     case h do
       "-" <> _ -> shared_option?(list, config, &parse_iex(&1, &2))
@@ -444,15 +395,6 @@ defmodule Kernel.CLI do
     wrapper(fn -> Code.eval_string(expr, []) end)
   end
 
-  defp process_command({:rpc_eval, node, expr}, _config) when is_binary(expr) do
-    case :rpc.call(String.to_atom(node), __MODULE__, :rpc_eval, [expr]) do
-      :ok -> :ok
-      {:badrpc, {:EXIT, exit}} -> Process.exit(self(), exit)
-      {:badrpc, reason} -> {:error, "--rpc-eval : RPC failed with reason #{inspect(reason)}"}
-      {kind, error, stack} -> :erlang.raise(kind, error, stack)
-    end
-  end
-
   defp process_command({:app, app}, _config) when is_binary(app) do
     case Application.ensure_all_started(String.to_atom(app)) do
       {:error, {app, reason}} ->
@@ -517,25 +459,13 @@ defmodule Kernel.CLI do
         wrapper(fn ->
           Code.compiler_options(config.compiler_options)
 
-          verbose_opts =
+          opts =
             if config.verbose_compile do
-              [each_file: &IO.puts("Compiling #{Path.relative_to_cwd(&1)}")]
-            else
-              [
-                each_long_compilation:
-                  &IO.puts("Compiling #{Path.relative_to_cwd(&1)} (it's taking more than 10s)")
-              ]
-            end
-
-          profile_opts =
-            if config.profile do
-              [profile: config.profile]
+              [each_long_compilation: &IO.puts("Compiling #{&1} (it's taking more than 15s)")]
             else
               []
             end
 
-          opts = verbose_opts ++ profile_opts
-
           case Kernel.ParallelCompiler.compile_to_path(files, config.output, opts) do
             {:ok, _, _} -> :ok
             {:error, _, _} -> exit({:shutdown, 1})
@@ -549,7 +479,6 @@ defmodule Kernel.CLI do
 
   defp filter_patterns(pattern) do
     pattern
-    |> Path.expand()
     |> Path.wildcard()
     |> :lists.usort()
     |> Enum.filter(&File.regular?/1)

lib/elixir/lib/kernel/error_handler.ex

@@ -5,13 +5,13 @@ defmodule Kernel.ErrorHandler do
 
   @spec undefined_function(module, atom, list) :: term
   def undefined_function(module, fun, args) do
-    ensure_loaded(module) or ensure_compiled(module, :module, :raise)
+    ensure_loaded(module) or ensure_compiled(module, :module)
     :error_handler.undefined_function(module, fun, args)
   end
 
   @spec undefined_lambda(module, fun, list) :: term
   def undefined_lambda(module, fun, args) do
-    ensure_loaded(module) or ensure_compiled(module, :module, :raise)
+    ensure_loaded(module) or ensure_compiled(module, :module)
     :error_handler.undefined_lambda(module, fun, args)
   end
 
@@ -23,21 +23,21 @@ defmodule Kernel.ErrorHandler do
     end
   end
 
-  @spec ensure_compiled(module, atom, atom) :: :found | :not_found | :deadlock
+  @spec ensure_compiled(module, atom) :: boolean
   # Never wait on nil because it should never be defined.
-  def ensure_compiled(nil, _kind, _deadlock) do
-    :not_found
+  def ensure_compiled(nil, _kind) do
+    false
   end
 
-  def ensure_compiled(module, kind, deadlock) do
-    {compiler_pid, file_pid} = :erlang.get(:elixir_compiler_info)
+  def ensure_compiled(module, kind) do
+    parent = :erlang.get(:elixir_compiler_pid)
     ref = :erlang.make_ref()
-    modules = :elixir_module.compiler_modules()
-    send(compiler_pid, {:waiting, kind, self(), ref, file_pid, module, modules, deadlock})
+    send(parent, {:waiting, kind, self(), ref, module, :elixir_module.compiler_modules()})
     :erlang.garbage_collect(self())
 
     receive do
-      {^ref, value} -> value
+      {^ref, :found} -> true
+      {^ref, :not_found} -> false
     end
   end
 end

lib/elixir/lib/kernel/lexical_tracker.ex

@@ -6,14 +6,28 @@
 # any of the `GenServer.Behaviour` conveniences.
 defmodule Kernel.LexicalTracker do
   @moduledoc false
-  @timeout :infinity
+  @timeout 30000
   @behaviour :gen_server
 
   @doc """
-  Returns all references in this lexical scope.
+  Returns all remotes referenced in this lexical scope.
   """
-  def references(pid) do
-    :gen_server.call(pid, :references, @timeout)
+  def remote_references(arg) do
+    :gen_server.call(to_pid(arg), :remote_references, @timeout)
+  end
+
+  @doc """
+  Returns all remote dispatches in this lexical scope.
+  """
+  def remote_dispatches(arg) do
+    :gen_server.call(to_pid(arg), :remote_dispatches, @timeout)
+  end
+
+  defp to_pid(pid) when is_pid(pid), do: pid
+
+  defp to_pid(mod) when is_atom(mod) do
+    {set, _} = :elixir_module.data_tables(mod)
+    :ets.lookup_element(set, {:elixir, :lexical_tracker}, 2)
   end
 
   # Internal API
@@ -26,12 +40,7 @@ defmodule Kernel.LexicalTracker do
 
   @doc false
   def stop(pid) do
-    :gen_server.call(pid, :stop)
-  end
-
-  @doc false
-  def add_export(pid, module) when is_atom(module) do
-    :gen_server.cast(pid, {:add_export, module})
+    :gen_server.cast(pid, :stop)
   end
 
   @doc false
@@ -45,13 +54,23 @@ defmodule Kernel.LexicalTracker do
   end
 
   @doc false
-  def remote_dispatch(pid, module, mode) when is_atom(module) do
-    :gen_server.cast(pid, {:remote_dispatch, module, mode})
+  def remote_reference(pid, module, mode) when is_atom(module) do
+    :gen_server.cast(pid, {:remote_reference, module, mode})
   end
 
   @doc false
-  def import_dispatch(pid, module, fa, mode) when is_atom(module) do
-    :gen_server.cast(pid, {:import_dispatch, module, fa, mode})
+  def remote_dispatch(pid, module, fa, line, mode) when is_atom(module) do
+    :gen_server.cast(pid, {:remote_dispatch, module, fa, line, mode})
+  end
+
+  @doc false
+  def remote_struct(pid, module, line) when is_atom(module) do
+    :gen_server.cast(pid, {:remote_struct, module, line})
+  end
+
+  @doc false
+  def import_dispatch(pid, module, fa, line, mode) when is_atom(module) do
+    :gen_server.cast(pid, {:import_dispatch, module, fa, line, mode})
   end
 
   @doc false
@@ -59,16 +78,6 @@ defmodule Kernel.LexicalTracker do
     :gen_server.cast(pid, {:alias_dispatch, module})
   end
 
-  @doc false
-  def import_quoted(pid, module, function, arities) when is_atom(module) do
-    :gen_server.cast(pid, {:import_quoted, module, function, arities})
-  end
-
-  @doc false
-  def add_compile_env(pid, app, path, return) do
-    :gen_server.cast(pid, {:compile_env, app, path, return})
-  end
-
   @doc false
   def set_file(pid, file) do
     :gen_server.cast(pid, {:set_file, file})
@@ -93,28 +102,28 @@ defmodule Kernel.LexicalTracker do
 
   @doc false
   def collect_unused_imports(pid) do
-    unused(pid, :unused_imports)
+    unused(pid, :import)
   end
 
   @doc false
   def collect_unused_aliases(pid) do
-    unused(pid, :unused_aliases)
+    unused(pid, :alias)
   end
 
   defp unused(pid, tag) do
-    :gen_server.call(pid, tag, @timeout)
+    :gen_server.call(pid, {:unused, tag}, @timeout)
   end
 
   # Callbacks
 
   def init(:ok) do
     state = %{
-      aliases: %{},
-      imports: %{},
+      directives: %{},
       references: %{},
-      exports: %{},
+      compile: %{},
+      runtime: %{},
+      structs: %{},
       cache: %{},
-      compile_env: :ordsets.new(),
       file: nil
     }
 
@@ -122,75 +131,59 @@ defmodule Kernel.LexicalTracker do
   end
 
   @doc false
-  def handle_call(:unused_aliases, _from, state) do
-    {:reply, Enum.sort(state.aliases), state}
+  def handle_call({:unused, tag}, _from, state) do
+    directives =
+      for {{^tag, module_or_mfa}, marker} <- state.directives, is_integer(marker) do
+        {module_or_mfa, marker}
+      end
+
+    {:reply, Enum.sort(directives), state}
   end
 
-  def handle_call(:unused_imports, _from, state) do
-    {:reply, Enum.sort(state.imports), state}
+  def handle_call(:remote_references, _from, state) do
+    {compile, runtime} = partition(:maps.to_list(state.references), [], [])
+    {:reply, {compile, :maps.keys(state.structs), runtime}, state}
   end
 
-  def handle_call(:references, _from, state) do
-    {compile, runtime} = partition(Map.to_list(state.references), [], [])
-    {:reply, {compile, Map.keys(state.exports), runtime, state.compile_env}, state}
+  def handle_call(:remote_dispatches, _from, state) do
+    {:reply, {state.compile, state.runtime}, state}
   end
 
   def handle_call({:read_cache, key}, _from, %{cache: cache} = state) do
-    {:reply, Map.get(cache, key), state}
-  end
-
-  def handle_call(:stop, _from, state) do
-    {:stop, :normal, :ok, state}
+    {:reply, :maps.get(key, cache), state}
   end
 
   def handle_cast({:write_cache, key, value}, %{cache: cache} = state) do
-    {:noreply, %{state | cache: Map.put(cache, key, value)}}
+    {:noreply, %{state | cache: :maps.put(key, value, cache)}}
   end
 
-  def handle_cast({:remote_dispatch, module, mode}, state) do
+  def handle_cast({:remote_reference, module, mode}, state) do
+    {:noreply, %{state | references: add_reference(state.references, module, mode)}}
+  end
+
+  def handle_cast({:remote_struct, module, line}, state) do
+    state = add_remote_dispatch(state, module, {:__struct__, 1}, line, :compile)
+    structs = :maps.put(module, true, state.structs)
+    {:noreply, %{state | structs: structs}}
+  end
+
+  def handle_cast({:remote_dispatch, module, fa, line, mode}, state) do
     references = add_reference(state.references, module, mode)
+    state = add_remote_dispatch(state, module, fa, line, mode)
     {:noreply, %{state | references: references}}
   end
 
-  def handle_cast({:import_dispatch, module, {function, arity}, mode}, state) do
-    %{imports: imports, references: references} = state
+  def handle_cast({:import_dispatch, module, {function, arity} = fa, line, mode}, state) do
+    state =
+      state
+      |> add_import_dispatch(module, function, arity)
+      |> add_remote_dispatch(module, fa, line, mode)
 
-    imports =
-      case imports do
-        %{^module => modules_and_fas} ->
-          modules_and_fas
-          |> Map.delete(module)
-          |> Map.delete({function, arity})
-          |> then(&Map.put(imports, module, &1))
-
-        %{} ->
-          imports
-      end
-
-    references = add_reference(references, module, mode)
-    {:noreply, %{state | imports: imports, references: references}}
+    {:noreply, state}
   end
 
-  def handle_cast({:alias_dispatch, module}, %{aliases: aliases} = state) do
-    {:noreply, %{state | aliases: Map.delete(aliases, module)}}
-  end
-
-  def handle_cast({:import_quoted, module, function, arities}, state) do
-    %{imports: imports} = state
-
-    imports =
-      case imports do
-        %{^module => modules_and_fas} ->
-          arities
-          |> Enum.reduce(modules_and_fas, &Map.delete(&2, {function, &1}))
-          |> Map.delete(module)
-          |> then(&Map.put(imports, module, &1))
-
-        %{} ->
-          imports
-      end
-
-    {:noreply, %{state | imports: imports}}
+  def handle_cast({:alias_dispatch, module}, state) do
+    {:noreply, %{state | directives: add_dispatch(state.directives, module, :alias)}}
   end
 
   def handle_cast({:set_file, file}, state) do
@@ -201,29 +194,27 @@ defmodule Kernel.LexicalTracker do
     {:noreply, %{state | file: nil}}
   end
 
-  def handle_cast({:compile_env, app, path, return}, state) do
-    {:noreply, update_in(state.compile_env, &:ordsets.add_element({app, path, return}, &1))}
-  end
-
-  def handle_cast({:add_export, module}, state) do
-    {:noreply, put_in(state.exports[module], true)}
-  end
-
   def handle_cast({:add_import, module, fas, line, warn}, state) do
-    if warn do
-      imports = for module_or_fa <- [module | fas], do: {module_or_fa, line}, into: %{}
-      {:noreply, put_in(state.imports[module], imports)}
-    else
-      {:noreply, state}
-    end
+    directives =
+      state.directives
+      |> Enum.reject(&match?({{:import, {^module, _, _}}, _}, &1))
+      |> :maps.from_list()
+      |> add_directive(module, line, warn, :import)
+
+    directives =
+      Enum.reduce(fas, directives, fn {function, arity}, directives ->
+        add_directive(directives, {module, function, arity}, line, warn, :import)
+      end)
+
+    {:noreply, %{state | directives: directives}}
   end
 
   def handle_cast({:add_alias, module, line, warn}, state) do
-    if warn do
-      {:noreply, put_in(state.aliases[module], line)}
-    else
-      {:noreply, state}
-    end
+    {:noreply, %{state | directives: add_directive(state.directives, module, line, warn, :alias)}}
+  end
+
+  def handle_cast(:stop, state) do
+    {:stop, :normal, state}
   end
 
   @doc false
@@ -252,12 +243,56 @@ defmodule Kernel.LexicalTracker do
   # Callbacks helpers
 
   defp add_reference(references, module, :compile) when is_atom(module),
-    do: Map.put(references, module, :compile)
+    do: :maps.put(module, :compile, references)
 
   defp add_reference(references, module, :runtime) when is_atom(module) do
-    case references do
-      %{^module => _} -> references
-      %{} -> Map.put(references, module, :runtime)
+    case :maps.find(module, references) do
+      {:ok, _} -> references
+      :error -> :maps.put(module, :runtime, references)
+    end
+  end
+
+  defp add_remote_dispatch(state, module, fa, line, mode) when is_atom(module) do
+    location = location(state.file, line)
+
+    map_update(mode, %{module => %{fa => [location]}}, state, fn mode_dispatches ->
+      map_update(module, %{fa => [location]}, mode_dispatches, fn module_dispatches ->
+        map_update(fa, [location], module_dispatches, &[location | List.delete(&1, location)])
+      end)
+    end)
+  end
+
+  defp location(nil, line), do: line
+  defp location(file, line), do: {file, line}
+
+  defp add_import_dispatch(state, module, function, arity) do
+    directives =
+      add_dispatch(state.directives, module, :import)
+      |> add_dispatch({module, function, arity}, :import)
+
+    # Always compile time because we depend
+    # on the module at compile time
+    references = add_reference(state.references, module, :compile)
+
+    %{state | directives: directives, references: references}
+  end
+
+  # In the map we keep imports and aliases.
+  # If the value is a line, it was imported/aliased and has a pending warning
+  # If the value is true, it was imported/aliased and used
+  defp add_directive(directives, module_or_mfa, line, warn, tag) do
+    marker = if warn, do: line, else: true
+    :maps.put({tag, module_or_mfa}, marker, directives)
+  end
+
+  defp add_dispatch(directives, module_or_mfa, tag) do
+    :maps.put({tag, module_or_mfa}, true, directives)
+  end
+
+  defp map_update(key, initial, map, fun) do
+    case :maps.find(key, map) do
+      {:ok, val} -> :maps.put(key, fun.(val), map)
+      :error -> :maps.put(key, initial, map)
     end
   end
 end

lib/elixir/lib/kernel/parallel_compiler.ex

@@ -3,12 +3,6 @@ defmodule Kernel.ParallelCompiler do
   A module responsible for compiling and requiring files in parallel.
   """
 
-  @typedoc "The line. 0 indicates no line."
-  @type line() :: non_neg_integer()
-  @type location() :: line() | {pos_integer(), column :: non_neg_integer}
-  @type warning() :: {file :: Path.t(), location(), message :: String.t()}
-  @type error() :: {file :: Path.t(), location(), message :: String.t()}
-
   @doc """
   Starts a task for parallel compilation.
 
@@ -21,29 +15,23 @@ defmodule Kernel.ParallelCompiler do
   always awaited on by calling `Task.await/1`
   """
   @doc since: "1.6.0"
-  def async(fun) when is_function(fun, 0) do
-    case :erlang.get(:elixir_compiler_info) do
-      {compiler, _} ->
-        file = :erlang.get(:elixir_compiler_file)
-        dest = :erlang.get(:elixir_compiler_dest)
+  def async(fun) when is_function(fun) do
+    if parent = :erlang.get(:elixir_compiler_pid) do
+      file = :erlang.get(:elixir_compiler_file)
+      dest = :erlang.get(:elixir_compiler_dest)
+      {:error_handler, error_handler} = :erlang.process_info(self(), :error_handler)
 
-        {:error_handler, error_handler} = :erlang.process_info(self(), :error_handler)
-        {_parent, checker} = Module.ParallelChecker.get()
-
-        Task.async(fn ->
-          send(compiler, {:async, self()})
-          Module.ParallelChecker.put(compiler, checker)
-          :erlang.put(:elixir_compiler_info, {compiler, self()})
-          :erlang.put(:elixir_compiler_file, file)
-          dest != :undefined and :erlang.put(:elixir_compiler_dest, dest)
-          :erlang.process_flag(:error_handler, error_handler)
-          fun.()
-        end)
-
-      :undefined ->
-        raise ArgumentError,
-              "cannot spawn parallel compiler task because " <>
-                "the current file is not being compiled/required"
+      Task.async(fn ->
+        :erlang.put(:elixir_compiler_pid, parent)
+        :erlang.put(:elixir_compiler_file, file)
+        dest != :undefined and :erlang.put(:elixir_compiler_dest, dest)
+        :erlang.process_flag(:error_handler, error_handler)
+        fun.()
+      end)
+    else
+      raise ArgumentError,
+            "cannot spawn parallel compiler task because " <>
+              "the current file is not being compiled/required"
     end
   end
 
@@ -57,7 +45,7 @@ defmodule Kernel.ParallelCompiler do
 
   It returns `{:ok, modules, warnings}` or `{:error, errors, warnings}`.
 
-  Both errors and warnings are a list of three-element tuples containing
+  Both errors and warnings are a list of three element tuples containing
   the file, line and the formatted error/warning.
 
   ## Options
@@ -73,43 +61,23 @@ defmodule Kernel.ParallelCompiler do
       the file, module and the module bytecode
 
     * `:each_cycle` - after the given files are compiled, invokes this function
-      that should return the following values:
-      * `{:compile, modules, warnings}` - to continue compilation with a list of
-        further modules to compile
-      * `{:runtime, modules, warnings}` - to stop compilation and verify the list
-        of modules because dependent modules have changed
+      that return a list with potentially more files to compile
 
-    * `:long_compilation_threshold` - the timeout (in seconds) to check for modules
-      taking too long to compile. For each file that exceeds the threshold, the
-      `:each_long_compilation` callback is invoked. From Elixir v1.11, only the time
-      spent compiling the actual module is taken into account by the threshold, the
-      time spent waiting is not considered. Defaults to `10` seconds.
+    * `:long_compilation_threshold` - the timeout (in seconds) after the
+      `:each_long_compilation` callback is invoked; defaults to `15`
 
-    * `:profile` - if set to `:time` measure the compilation time of each compilation cycle
-       and group pass checker
-
-    * `:dest` - the destination directory for the BEAM files. When using `compile/2`,
+    * `:dest` - the destination directory for the BEAM files. When using `files/2`,
       this information is only used to properly annotate the BEAM files before
       they are loaded into memory. If you want a file to actually be written to
       `dest`, use `compile_to_path/3` instead.
 
-    * `:beam_timestamp` - the modification timestamp to give all BEAM files
-
   """
   @doc since: "1.6.0"
-  @spec compile([Path.t()], keyword()) :: {:ok, [atom], [warning]} | {:error, [error], [warning]}
   def compile(files, options \\ []) when is_list(options) do
     spawn_workers(files, :compile, options)
   end
 
-  @doc """
-  Compiles the given files and writes resulting BEAM files into path.
-
-  See `compile/2` for more information.
-  """
   @doc since: "1.6.0"
-  @spec compile_to_path([Path.t()], Path.t(), keyword()) ::
-          {:ok, [atom], [warning]} | {:error, [error], [warning]}
   def compile_to_path(files, path, options \\ []) when is_binary(path) and is_list(options) do
     spawn_workers(files, {:compile, path}, options)
   end
@@ -122,7 +90,7 @@ defmodule Kernel.ParallelCompiler do
 
   It returns `{:ok, modules, warnings}` or `{:error, errors, warnings}`.
 
-  Both errors and warnings are a list of three-element tuples containing
+  Both errors and warnings are a list of three element tuples containing
   the file, line and the formatted error/warning.
 
   ## Options
@@ -135,23 +103,12 @@ defmodule Kernel.ParallelCompiler do
 
   """
   @doc since: "1.6.0"
-  @spec require([Path.t()], keyword()) ::
-          {:ok, [atom], [warning]} | {:error, [error], [warning]}
   def require(files, options \\ []) when is_list(options) do
     spawn_workers(files, :require, options)
   end
 
-  @doc """
-  Prints a warning returned by the compiler.
-  """
-  @doc since: "1.13.0"
-  @spec print_warning(warning) :: :ok
-  def print_warning({file, location, warning}) do
-    :elixir_errors.print_warning(location, file, warning)
-  end
-
+  # TODO: Deprecate on Elixir v1.8
   @doc false
-  @deprecated "Use Kernel.ParallelCompiler.compile/2 instead"
   def files(files, options \\ []) when is_list(options) do
     case spawn_workers(files, :compile, options) do
       {:ok, modules, _} -> modules
@@ -159,8 +116,8 @@ defmodule Kernel.ParallelCompiler do
     end
   end
 
+  # TODO: Deprecate on Elixir v1.8
   @doc false
-  @deprecated "Use Kernel.ParallelCompiler.compile_to_path/2 instead"
   def files_to_path(files, path, options \\ []) when is_binary(path) and is_list(options) do
     case spawn_workers(files, {:compile, path}, options) do
       {:ok, modules, _} -> modules
@@ -170,371 +127,189 @@ defmodule Kernel.ParallelCompiler do
 
   defp spawn_workers(files, output, options) do
     {:module, _} = :code.ensure_loaded(Kernel.ErrorHandler)
+    compiler_pid = self()
+    :elixir_code_server.cast({:reset_warnings, compiler_pid})
     schedulers = max(:erlang.system_info(:schedulers_online), 2)
-    {:ok, checker} = Module.ParallelChecker.start_link(schedulers)
 
-    try do
-      outcome = spawn_workers(schedulers, checker, files, output, options)
-      {outcome, Code.get_compiler_option(:warnings_as_errors)}
-    else
-      {{:ok, _, [_ | _] = warnings}, true} ->
+    result =
+      spawn_workers(files, [], [], [], [], %{
+        dest: Keyword.get(options, :dest),
+        each_cycle: Keyword.get(options, :each_cycle, fn -> [] end),
+        each_file: Keyword.get(options, :each_file, fn _file -> :ok end),
+        each_long_compilation: Keyword.get(options, :each_long_compilation, fn _file -> :ok end),
+        each_module: Keyword.get(options, :each_module, fn _file, _module, _binary -> :ok end),
+        output: output,
+        long_compilation_threshold: Keyword.get(options, :long_compilation_threshold, 15),
+        schedulers: schedulers
+      })
+
+    # In case --warning-as-errors is enabled and there was a warning,
+    # compilation status will be set to error.
+    compilation_status = :elixir_code_server.call({:compilation_status, compiler_pid})
+
+    case {result, compilation_status} do
+      {{:ok, _, warnings}, :error} ->
         message = "Compilation failed due to warnings while using the --warnings-as-errors option"
         IO.puts(:stderr, message)
         {:error, warnings, []}
 
-      {{:ok, outcome, warnings}, _} ->
-        beam_timestamp = Keyword.get(options, :beam_timestamp)
-        {:ok, write_module_binaries(outcome, output, beam_timestamp), warnings}
-
-      {{:error, errors, warnings}, true} ->
+      {{:error, errors, warnings}, :error} ->
         {:error, errors ++ warnings, []}
 
-      {{:error, errors, warnings}, _} ->
-        {:error, errors, warnings}
-    after
-      Module.ParallelChecker.stop(checker)
-    end
-  end
-
-  defp spawn_workers(schedulers, checker, files, output, options) do
-    threshold = Keyword.get(options, :long_compilation_threshold, 10) * 1000
-    timer_ref = Process.send_after(self(), :threshold_check, threshold)
-
-    {outcome, state} =
-      spawn_workers(files, 0, [], [], %{}, [], %{
-        dest: Keyword.get(options, :dest),
-        each_cycle: Keyword.get(options, :each_cycle, fn -> {:runtime, [], []} end),
-        each_file: Keyword.get(options, :each_file, fn _, _ -> :ok end) |> each_file(),
-        each_long_compilation: Keyword.get(options, :each_long_compilation, fn _file -> :ok end),
-        each_module: Keyword.get(options, :each_module, fn _file, _module, _binary -> :ok end),
-        profile: profile_init(Keyword.get(options, :profile)),
-        output: output,
-        timer_ref: timer_ref,
-        long_compilation_threshold: threshold,
-        schedulers: schedulers,
-        checker: checker
-      })
-
-    Process.cancel_timer(state.timer_ref)
-
-    receive do
-      :threshold_check -> :ok
-    after
-      0 -> :ok
-    end
-
-    outcome
-  end
-
-  defp each_file(fun) when is_function(fun, 1), do: fn file, _ -> fun.(file) end
-  defp each_file(fun) when is_function(fun, 2), do: fun
-
-  defp each_file(file, lexical, parent) do
-    ref = Process.monitor(parent)
-    send(parent, {:file_ok, self(), ref, file, lexical})
-
-    receive do
-      ^ref -> :ok
-      {:DOWN, ^ref, _, _, _} -> :ok
-    end
-  end
-
-  defp write_module_binaries(result, {:compile, path}, timestamp) do
-    Enum.flat_map(result, fn
-      {{:module, module}, binary} ->
-        full_path = Path.join(path, Atom.to_string(module) <> ".beam")
-        File.write!(full_path, binary)
-        if timestamp, do: File.touch!(full_path, timestamp)
-        [module]
-
       _ ->
-        []
-    end)
+        result
+    end
   end
 
-  defp write_module_binaries(result, _output, _timestamp) do
-    for {{:module, module}, _} <- result, do: module
-  end
-
-  ## Verification
-
-  defp verify_modules(result, warnings, dependent_modules, state) do
-    checker_warnings = maybe_check_modules(result, dependent_modules, state)
-    warnings = Enum.reverse(warnings, checker_warnings)
-    {{:ok, result, warnings}, state}
-  end
-
-  defp maybe_check_modules(result, runtime_modules, state) do
-    %{profile: profile, checker: checker} = state
-
-    compiled_modules =
-      for {{:module, module}, _} <- result,
-          do: module
-
-    runtime_modules =
-      for module <- runtime_modules,
-          path = :code.which(module),
-          is_list(path) and path != [],
-          do: {module, path}
-
-    profile_checker(profile, compiled_modules, runtime_modules, fn ->
-      Module.ParallelChecker.verify(checker, runtime_modules)
-    end)
-  end
-
-  defp profile_init(:time), do: {:time, System.monotonic_time(), 0}
-  defp profile_init(nil), do: :none
-
-  defp profile_checker({:time, _, _}, compiled_modules, runtime_modules, fun) do
-    {time, result} = :timer.tc(fun)
-    time = div(time, 1000)
-    num_modules = length(compiled_modules) + length(runtime_modules)
-    IO.puts(:stderr, "[profile] Finished group pass check of #{num_modules} modules in #{time}ms")
-    result
-  end
-
-  defp profile_checker(:none, _compiled_modules, _runtime_modules, fun) do
-    fun.()
-  end
-
-  ## Compiler worker spawning
-
   # We already have n=schedulers currently running, don't spawn new ones
-  defp spawn_workers(
-         queue,
-         spawned,
-         waiting,
-         files,
-         result,
-         warnings,
-         %{schedulers: schedulers} = state
-       )
-       when spawned - length(waiting) >= schedulers do
-    wait_for_messages(queue, spawned, waiting, files, result, warnings, state)
+  defp spawn_workers(files, waiting, queued, result, warnings, %{schedulers: schedulers} = state)
+       when length(queued) - length(waiting) >= schedulers do
+    wait_for_messages(files, waiting, queued, result, warnings, state)
   end
 
   # Release waiting processes
-  defp spawn_workers([{ref, found} | t], spawned, waiting, files, result, warnings, state) do
-    {files, waiting} =
+  defp spawn_workers([{ref, found} | t], waiting, queued, result, warnings, state) do
+    waiting =
       case List.keytake(waiting, ref, 2) do
-        {{_kind, pid, ^ref, file_pid, _on, _defining, _deadlock}, waiting} ->
+        {{_kind, pid, ^ref, _on, _defining}, waiting} ->
           send(pid, {ref, found})
-          {update_timing(files, file_pid, :waiting), waiting}
+          waiting
 
         nil ->
-          # In case the waiting process died (for example, it was an async process),
-          # it will no longer be on the list. So we need to take it into account here.
-          {files, waiting}
+          waiting
       end
 
-    spawn_workers(t, spawned, waiting, files, result, warnings, state)
+    spawn_workers(t, waiting, queued, result, warnings, state)
   end
 
-  defp spawn_workers([file | queue], spawned, waiting, files, result, warnings, state) do
-    %{output: output, dest: dest, checker: checker} = state
+  defp spawn_workers([file | files], waiting, queued, result, warnings, state) do
+    %{output: output, long_compilation_threshold: threshold, dest: dest} = state
     parent = self()
-    file = Path.expand(file)
 
     {pid, ref} =
       :erlang.spawn_monitor(fn ->
-        Module.ParallelChecker.put(parent, checker)
-        :erlang.put(:elixir_compiler_info, {parent, self()})
+        :erlang.put(:elixir_compiler_pid, parent)
         :erlang.put(:elixir_compiler_file, file)
 
-        try do
-          case output do
-            {:compile, path} -> compile_file(file, path, parent)
-            :compile -> compile_file(file, dest, parent)
-            :require -> require_file(file, parent)
-          end
-        catch
-          kind, reason ->
-            send(parent, {:file_error, self(), file, {kind, reason, __STACKTRACE__}})
-        end
+        result =
+          try do
+            _ =
+              case output do
+                {:compile, path} ->
+                  :erlang.process_flag(:error_handler, Kernel.ErrorHandler)
+                  :erlang.put(:elixir_compiler_dest, path)
+                  :elixir_compiler.file_to_path(Path.expand(file), path)
 
+                :compile ->
+                  :erlang.process_flag(:error_handler, Kernel.ErrorHandler)
+                  :erlang.put(:elixir_compiler_dest, dest)
+                  Code.compile_file(file)
+
+                :require ->
+                  Code.require_file(file)
+              end
+
+            :ok
+          catch
+            kind, reason ->
+              {kind, reason, __STACKTRACE__}
+          end
+
+        send(parent, {:file_done, self(), file, result})
         exit(:shutdown)
       end)
 
-    file_data = %{
-      pid: pid,
-      ref: ref,
-      file: file,
-      timestamp: System.monotonic_time(),
-      compiling: 0,
-      waiting: 0,
-      warned: false
-    }
-
-    files = [file_data | files]
-    spawn_workers(queue, spawned + 1, waiting, files, result, warnings, state)
+    timer_ref = Process.send_after(self(), {:timed_out, pid}, threshold * 1000)
+    queued = [{pid, ref, file, timer_ref} | queued]
+    spawn_workers(files, waiting, queued, result, warnings, state)
   end
 
-  # No more queue, nothing waiting, this cycle is done
-  defp spawn_workers([], 0, [], [], result, warnings, state) do
-    cycle_return = each_cycle_return(state.each_cycle.())
-    state = cycle_timing(result, state)
+  # No more files, nothing waiting, queue is empty, this cycle is done
+  defp spawn_workers([], [], [], result, warnings, state) do
+    case state.each_cycle.() do
+      [] ->
+        modules = for {:module, mod} <- result, do: mod
+        warnings = Enum.reverse(warnings)
+        {:ok, modules, warnings}
 
-    case cycle_return do
-      {:runtime, dependent_modules, extra_warnings} ->
-        verify_modules(result, extra_warnings ++ warnings, dependent_modules, state)
-
-      {:compile, [], extra_warnings} ->
-        verify_modules(result, extra_warnings ++ warnings, [], state)
-
-      {:compile, more, extra_warnings} ->
-        spawn_workers(more, 0, [], [], result, extra_warnings ++ warnings, state)
+      more ->
+        spawn_workers(more, [], [], result, warnings, state)
     end
   end
 
-  # files x, waiting for x: POSSIBLE ERROR! Release processes so we get the failures
+  # Queued x, waiting for x: POSSIBLE ERROR! Release processes so we get the failures
 
   # Single entry, just release it.
-  defp spawn_workers(
-         [],
-         1,
-         [{_, pid, ref, _, _, _, _}] = waiting,
-         [%{pid: pid}] = files,
-         result,
-         warnings,
-         state
-       ) do
-    spawn_workers([{ref, :not_found}], 1, waiting, files, result, warnings, state)
+  defp spawn_workers([], [_] = waiting, [_] = queued, result, warnings, state) do
+    [{_, _, ref, _, _}] = waiting
+    spawn_workers([{ref, :not_found}], waiting, queued, result, warnings, state)
   end
 
   # Multiple entries, try to release modules.
-  defp spawn_workers([], spawned, waiting, files, result, warnings, state)
-       when length(waiting) == spawned do
-    # There is potentially a deadlock. We will release modules with
-    # the following order:
-    #
-    #   1. Code.ensure_compiled/1 checks without a known definition (deadlock = soft)
-    #   2. Code.ensure_compiled/1 checks with a known definition (deadlock = soft)
-    #   3. Struct/import/require/ensure_compiled! checks without a known definition (deadlock = hard)
-    #   4. Modules without a known definition
-    #   5. Code invocation (deadlock = raise)
-    #
-    # The reason for step 3 and 4 is to not treat typos as deadlocks and
-    # help developers handle those sooner. However, this can have false
-    # positives in case multiple modules are defined in the same file
-    # and the module we are waiting for is defined later on.
-    #
-    # Finally, note there is no difference between hard and raise, the
-    # difference is where the raise is happening, inside the compiler
-    # or in the caller.
+  defp spawn_workers([], waiting, queued, result, warnings, state)
+       when length(waiting) == length(queued) do
+    # The goal of this function is to find leaves in the dependency graph,
+    # i.e. to find code that depends on code that we know is not being defined.
+    # Note we only release modules because those can be rescued. A missing
+    # struct is a guaranteed compile error, so we never release it and treat
+    # it exclusively a missing entry/deadlock.
+    pending =
+      for {pid, _, _, _} <- queued,
+          entry = waiting_on_without_definition(waiting, pid),
+          {kind, _, ref, on, _} = entry,
+          kind == :module,
+          do: {on, {ref, :not_found}}
 
-    deadlocked =
-      deadlocked(waiting, :soft, false) ||
-        deadlocked(waiting, :soft, true) || deadlocked(waiting, :hard, false) ||
-        without_definition(waiting, files)
+    # Instead of releasing all files at once, we release them in groups
+    # based on the module they are waiting on. We pick the module being
+    # depended on with less edges, as it is the mostly likely source of
+    # error (for example, someone made a typo). This may not always be
+    # true though. For example, if there is a macro injecting code into
+    # multiple modules and such code becomes faulty, now multiple modules
+    # are waiting on the same module required by the faulty code. However,
+    # since we need to pick something to be first, the one with fewer edges
+    # sounds like a sane choice.
+    pending
+    |> Enum.group_by(&elem(&1, 0), &elem(&1, 1))
+    |> Enum.sort_by(&length(elem(&1, 1)))
+    |> case do
+      [{_on, refs} | _] ->
+        spawn_workers(refs, waiting, queued, result, warnings, state)
 
-    if deadlocked do
-      spawn_workers(deadlocked, spawned, waiting, files, result, warnings, state)
+      [] ->
+        errors = handle_deadlock(waiting, queued)
+        {:error, errors, warnings}
+    end
+  end
+
+  # No more files, but queue and waiting are not full or do not match
+  defp spawn_workers([], waiting, queued, result, warnings, state) do
+    wait_for_messages([], waiting, queued, result, warnings, state)
+  end
+
+  defp waiting_on_without_definition(waiting, pid) do
+    {_, ^pid, _, on, _} = entry = List.keyfind(waiting, pid, 1)
+
+    if Enum.any?(waiting, fn {_, _, _, _, defining} -> on in defining end) do
+      nil
     else
-      errors = handle_deadlock(waiting, files)
-      {{:error, errors, warnings}, state}
+      entry
     end
   end
 
-  # No more queue, but spawned and length(waiting) do not match
-  defp spawn_workers([], spawned, waiting, files, result, warnings, state) do
-    wait_for_messages([], spawned, waiting, files, result, warnings, state)
-  end
-
-  defp compile_file(file, path, parent) do
-    :erlang.process_flag(:error_handler, Kernel.ErrorHandler)
-    :erlang.put(:elixir_compiler_dest, path)
-    :elixir_compiler.file(file, &each_file(&1, &2, parent))
-  end
-
-  defp require_file(file, parent) do
-    case :elixir_code_server.call({:acquire, file}) do
-      :required ->
-        send(parent, {:file_cancel, self()})
-
-      :proceed ->
-        :elixir_compiler.file(file, &each_file(&1, &2, parent))
-        :elixir_code_server.cast({:required, file})
-    end
-  end
-
-  defp cycle_timing(_result, %{profile: :none} = state) do
-    state
-  end
-
-  defp cycle_timing(result, %{profile: {:time, cycle_start, module_counter}} = state) do
-    num_modules = count_modules(result)
-    diff_modules = num_modules - module_counter
-    now = System.monotonic_time()
-    time = System.convert_time_unit(now - cycle_start, :native, :millisecond)
-
-    IO.puts(
-      :stderr,
-      "[profile] Finished compilation cycle of #{diff_modules} modules in #{time}ms"
-    )
-
-    %{state | profile: {:time, now, num_modules}}
-  end
-
-  defp count_modules(result) do
-    Enum.count(result, &match?({{:module, _}, _}, &1))
-  end
-
-  defp each_cycle_return({kind, modules, warnings}), do: {kind, modules, warnings}
-
-  defp each_cycle_return(other) do
-    IO.warn(
-      "the :each_cycle callback must return a tuple of format {:compile | :runtime, modules, warnings}"
-    )
-
-    case other do
-      {kind, modules} -> {kind, modules, []}
-      modules when is_list(modules) -> {:compile, modules, []}
-    end
-  end
-
-  # The goal of this function is to find leaves in the dependency graph,
-  # i.e. to find code that depends on code that we know is not being defined.
-  # Note that not all files have been compiled yet, so they may not be in waiting.
-  defp without_definition(waiting, files) do
-    nilify_empty(
-      for %{pid: pid} <- files,
-          {_, _, ref, ^pid, on, _, _} <- waiting,
-          not defining?(on, waiting),
-          do: {ref, :not_found}
-    )
-  end
-
-  defp deadlocked(waiting, type, defining?) do
-    nilify_empty(
-      for {_, _, ref, _, on, _, ^type} <- waiting,
-          defining?(on, waiting) == defining?,
-          do: {ref, :deadlock}
-    )
-  end
-
-  defp defining?(on, waiting) do
-    Enum.any?(waiting, fn {_, _, _, _, _, defining, _} -> on in defining end)
-  end
-
-  defp nilify_empty([]), do: nil
-  defp nilify_empty([_ | _] = list), do: list
-
   # Wait for messages from child processes
-  defp wait_for_messages(queue, spawned, waiting, files, result, warnings, state) do
+  defp wait_for_messages(files, waiting, queued, result, warnings, state) do
     %{output: output} = state
 
     receive do
-      {:async, process} ->
-        Process.monitor(process)
-        wait_for_messages(queue, spawned + 1, waiting, files, result, warnings, state)
-
-      {:available, kind, module} ->
+      {:struct_available, module} ->
         available =
-          for {^kind, _, ref, _, ^module, _defining, _deadlock} <- waiting,
+          for {:struct, _, ref, waiting_module, _defining} <- waiting,
+              module == waiting_module,
               do: {ref, :found}
 
-        result = Map.put(result, {kind, module}, true)
-        spawn_workers(available ++ queue, spawned, waiting, files, result, warnings, state)
+        result = [{:struct, module} | result]
+        spawn_workers(available ++ files, waiting, queued, result, warnings, state)
 
       {:module_available, child, ref, file, module, binary} ->
         state.each_module.(file, module, binary)
@@ -543,178 +318,112 @@ defmodule Kernel.ParallelCompiler do
         send(child, {ref, :ack})
 
         available =
-          for {:module, _, ref, _, ^module, _defining, _deadlock} <- waiting,
+          for {:module, _, ref, waiting_module, _defining} <- waiting,
+              module == waiting_module,
               do: {ref, :found}
 
-        result = Map.put(result, {:module, module}, binary)
-        spawn_workers(available ++ queue, spawned, waiting, files, result, warnings, state)
+        cancel_waiting_timer(queued, child)
+
+        result = [{:module, module} | result]
+        spawn_workers(available ++ files, waiting, queued, result, warnings, state)
 
       # If we are simply requiring files, we do not add to waiting.
-      {:waiting, _kind, child, ref, _file_pid, _on, _defining, _deadlock} when output == :require ->
+      {:waiting, _kind, child, ref, _on, _defining} when output == :require ->
         send(child, {ref, :not_found})
-        spawn_workers(queue, spawned, waiting, files, result, warnings, state)
+        spawn_workers(files, waiting, queued, result, warnings, state)
 
-      {:waiting, kind, child_pid, ref, file_pid, on, defining, deadlock?} ->
-        # If we already got what we were waiting for, do not put it on waiting.
-        # If we're waiting on ourselves, send :found so that we can crash with
-        # a better error.
-        {files, waiting} =
-          if Map.has_key?(result, {kind, on}) or on in defining do
-            send(child_pid, {ref, :found})
-            {files, waiting}
+      {:waiting, kind, child, ref, on, defining} ->
+        # Oops, we already got it, do not put it on waiting.
+        # Alternatively, we're waiting on ourselves,
+        # send :found so that we can crash with a better error.
+        waiting =
+          if :lists.any(&match?({^kind, ^on}, &1), result) or on in defining do
+            send(child, {ref, :found})
+            waiting
           else
-            files = update_timing(files, file_pid, :compiling)
-            {files, [{kind, child_pid, ref, file_pid, on, defining, deadlock?} | waiting]}
+            [{kind, child, ref, on, defining} | waiting]
           end
 
-        spawn_workers(queue, spawned, waiting, files, result, warnings, state)
+        spawn_workers(files, waiting, queued, result, warnings, state)
 
-      :threshold_check ->
-        files =
-          for data <- files do
-            if data.warned or List.keymember?(waiting, data.pid, 1) do
-              data
-            else
-              data = update_timing(data, :compiling)
-              data = maybe_warn_long_compilation(data, state)
-              data
-            end
-          end
+      {:timed_out, child} ->
+        case List.keyfind(queued, child, 0) do
+          {^child, _, file, _} ->
+            state.each_long_compilation.(file)
 
-        timer_ref = Process.send_after(self(), :threshold_check, state.long_compilation_threshold)
-        state = %{state | timer_ref: timer_ref}
-        spawn_workers(queue, spawned, waiting, files, result, warnings, state)
+          _ ->
+            :ok
+        end
 
-      {:warning, file, location, message} ->
+        spawn_workers(files, waiting, queued, result, warnings, state)
+
+      {:warning, file, line, message} ->
         file = file && Path.absname(file)
         message = :unicode.characters_to_binary(message)
-        warning = {file, location, message}
-        wait_for_messages(queue, spawned, waiting, files, result, [warning | warnings], state)
-
-      {:file_ok, child_pid, ref, file, lexical} ->
-        state.each_file.(file, lexical)
-        send(child_pid, ref)
+        warning = {file, line, message}
+        wait_for_messages(files, waiting, queued, result, [warning | warnings], state)
 
+      {:file_done, child_pid, file, :ok} ->
         discard_down(child_pid)
-        new_files = discard_and_maybe_log_file(files, child_pid, state)
+        state.each_file.(file)
+        cancel_waiting_timer(queued, child_pid)
 
-        # Sometimes we may have spurious entries in the waiting list
-        # because someone invoked try/rescue UndefinedFunctionError
+        # Sometimes we may have spurious entries in the waiting
+        # list because someone invoked try/rescue UndefinedFunctionError
+        new_files = List.delete(files, child_pid)
+        new_queued = List.keydelete(queued, child_pid, 0)
         new_waiting = List.keydelete(waiting, child_pid, 1)
-        spawn_workers(queue, spawned - 1, new_waiting, new_files, result, warnings, state)
+        spawn_workers(new_files, new_waiting, new_queued, result, warnings, state)
 
-      {:file_cancel, child_pid} ->
+      {:file_done, child_pid, file, {kind, reason, stack}} ->
         discard_down(child_pid)
-        new_files = Enum.reject(files, &(&1.pid == child_pid))
-        spawn_workers(queue, spawned - 1, waiting, new_files, result, warnings, state)
-
-      {:file_error, child_pid, file, {kind, reason, stack}} ->
         print_error(file, kind, reason, stack)
-        discard_down(child_pid)
-        files |> Enum.reject(&(&1.pid == child_pid)) |> terminate()
-        {{:error, [to_error(file, kind, reason, stack)], warnings}, state}
+        cancel_waiting_timer(queued, child_pid)
+        terminate(queued)
+        {:error, [to_error(file, kind, reason, stack)], warnings}
 
-      {:DOWN, ref, :process, pid, reason} ->
-        waiting = List.keydelete(waiting, pid, 1)
-
-        case handle_down(files, ref, reason) do
-          :ok -> wait_for_messages(queue, spawned - 1, waiting, files, result, warnings, state)
-          {:error, errors} -> {{:error, errors, warnings}, state}
+      {:DOWN, ref, :process, _pid, reason} ->
+        case handle_down(queued, ref, reason) do
+          :ok -> wait_for_messages(files, waiting, queued, result, warnings, state)
+          {:error, errors} -> {:error, errors, warnings}
         end
     end
   end
 
-  defp update_timing(files, pid, key) do
-    Enum.map(files, fn data ->
-      if data.pid == pid do
-        time = System.monotonic_time()
-        %{data | key => data[key] + time - data.timestamp, timestamp: time}
-      else
-        data
-      end
-    end)
-  end
-
-  defp update_timing(data, key) do
-    time = System.monotonic_time()
-    %{data | key => data[key] + time - data.timestamp, timestamp: time}
-  end
-
-  defp maybe_warn_long_compilation(data, state) do
-    compiling = System.convert_time_unit(data.compiling, :native, :millisecond)
-
-    if not data.warned and compiling >= state.long_compilation_threshold do
-      state.each_long_compilation.(data.file)
-      %{data | warned: true}
-    else
-      data
-    end
-  end
-
-  defp discard_and_maybe_log_file(files, pid, state) do
-    Enum.reject(files, fn data ->
-      if data.pid == pid do
-        data = update_timing(data, :compiling)
-        data = maybe_warn_long_compilation(data, state)
-
-        if state.profile != :none do
-          compiling = to_padded_ms(data.compiling)
-          waiting = to_padded_ms(data.waiting)
-          relative = Path.relative_to_cwd(data.file)
-
-          IO.puts(
-            :stderr,
-            "[profile] #{compiling}ms compiling + #{waiting}ms waiting for #{relative}"
-          )
-        end
-
-        true
-      else
-        false
-      end
-    end)
-  end
-
-  defp to_padded_ms(time) do
-    time
-    |> System.convert_time_unit(:native, :millisecond)
-    |> Integer.to_string()
-    |> String.pad_leading(6, " ")
-  end
-
   defp discard_down(pid) do
     receive do
       {:DOWN, _, :process, ^pid, _} -> :ok
     end
   end
 
-  defp handle_down(_files, _ref, :normal) do
+  defp handle_down(_queued, _ref, :normal) do
     :ok
   end
 
-  defp handle_down(files, ref, reason) do
-    case Enum.find(files, &(&1.ref == ref)) do
-      %{pid: pid, file: file} ->
+  defp handle_down(queued, ref, reason) do
+    case List.keyfind(queued, ref, 1) do
+      {_child, ^ref, file, _timer_ref} ->
         print_error(file, :exit, reason, [])
-        files |> Enum.reject(&(&1.pid == pid)) |> terminate()
+        terminate(queued)
         {:error, [to_error(file, :exit, reason, [])]}
 
-      nil ->
+      _ ->
         :ok
     end
   end
 
-  defp handle_deadlock(waiting, files) do
+  defp handle_deadlock(waiting, queued) do
     deadlock =
-      for %{pid: pid, file: file} <- files do
+      for {pid, _, file, _} <- queued do
         {:current_stacktrace, stacktrace} = Process.info(pid, :current_stacktrace)
         Process.exit(pid, :kill)
 
-        {kind, ^pid, _, _, on, _, _} = List.keyfind(waiting, pid, 1)
+        {kind, ^pid, _, on, _} = List.keyfind(waiting, pid, 1)
         description = "deadlocked waiting on #{kind} #{inspect(on)}"
         error = CompileError.exception(description: description, file: nil, line: nil)
         print_error(file, :error, error, stacktrace)
-        {Path.relative_to_cwd(file), on, description}
+
+        {file, on, description}
       end
 
     IO.puts("""
@@ -740,10 +449,10 @@ defmodule Kernel.ParallelCompiler do
     for {file, _, description} <- deadlock, do: {Path.absname(file), nil, description}
   end
 
-  defp terminate(files) do
-    for %{pid: pid} <- files, do: Process.exit(pid, :kill)
-    for %{pid: pid} <- files, do: discard_down(pid)
-    :ok
+  defp terminate(queued) do
+    for {pid, _, _, _} <- queued do
+      Process.exit(pid, :kill)
+    end
   end
 
   defp print_error(file, kind, reason, stack) do
@@ -753,16 +462,28 @@ defmodule Kernel.ParallelCompiler do
     ])
   end
 
+  defp cancel_waiting_timer(queued, child_pid) do
+    case List.keyfind(queued, child_pid, 0) do
+      {^child_pid, _ref, _file, timer_ref} ->
+        Process.cancel_timer(timer_ref)
+        # Let's flush the message in case it arrived before we canceled the
+        # timeout.
+        receive do
+          {:timed_out, ^child_pid} -> :ok
+        after
+          0 -> :ok
+        end
+
+      nil ->
+        :ok
+    end
+  end
+
   defp to_error(file, kind, reason, stack) do
     line = get_line(file, reason, stack)
     file = Path.absname(file)
     message = :unicode.characters_to_binary(Kernel.CLI.format_error(kind, reason, stack))
-    {file, line || 0, message}
-  end
-
-  defp get_line(_file, %{line: line, column: column}, _stack)
-       when is_integer(line) and line > 0 and is_integer(column) and column >= 0 do
-    {line, column}
+    {file, line, message}
   end
 
   defp get_line(_file, %{line: line}, _stack) when is_integer(line) and line > 0 do
@@ -775,13 +496,6 @@ defmodule Kernel.ParallelCompiler do
     end
   end
 
-  defp get_line(file, _reason, [{_, _, _, [file: expanding]}, {_, _, _, info} | _])
-       when expanding in ['expanding macro', 'expanding struct'] do
-    if Keyword.get(info, :file) == to_charlist(Path.relative_to_cwd(file)) do
-      Keyword.get(info, :line)
-    end
-  end
-
   defp get_line(file, _reason, [{_, _, _, info} | _]) do
     if Keyword.get(info, :file) == to_charlist(Path.relative_to_cwd(file)) do
       Keyword.get(info, :line)

lib/elixir/lib/kernel/parallel_require.ex

@@ -1,7 +1,7 @@
 defmodule Kernel.ParallelRequire do
+  # TODO: Deprecate on Elixir v1.8
   @moduledoc false
 
-  @deprecated "Use Kernel.ParallelCompiler.require/2 instead"
   def files(files, callbacks \\ [])
 
   def files(files, callback) when is_function(callback, 1) do

lib/elixir/lib/kernel/utils.ex

@@ -22,52 +22,16 @@ defmodule Kernel.Utils do
   defp destructure_nil(count), do: [nil | destructure_nil(count - 1)]
 
   @doc """
-  Callback for defdelegate entry point.
+  Callback for defdelegate.
   """
-  def defdelegate_all(funs, opts, env) do
-    to = Keyword.get(opts, :to) || raise ArgumentError, "expected to: to be given as argument"
-    as = Keyword.get(opts, :as)
-
-    if to == env.module and is_nil(as) do
-      raise ArgumentError,
-            "defdelegate function is calling itself, which will lead to an infinite loop. You should either change the value of the :to option or specify the :as option"
-    end
-
-    if is_list(funs) do
-      IO.warn(
-        "passing a list to Kernel.defdelegate/2 is deprecated, please define each delegate separately",
-        Macro.Env.stacktrace(env)
-      )
-    end
-
-    if Keyword.has_key?(opts, :append_first) do
-      IO.warn(
-        "Kernel.defdelegate/2 :append_first option is deprecated",
-        Macro.Env.stacktrace(env)
-      )
-    end
-
-    to
-  end
-
-  @doc """
-  Callback for each function in defdelegate.
-  """
-  def defdelegate_each(fun, opts) when is_list(opts) do
-    # TODO: Remove on v2.0
+  def defdelegate(fun, opts) when is_list(opts) do
+    # TODO: Remove by 2.0
     append_first? = Keyword.get(opts, :append_first, false)
 
     {name, args} =
-      case fun do
-        {:when, _, [_left, right]} ->
-          raise ArgumentError,
-                "guards are not allowed in defdelegate/2, got: when #{Macro.to_string(right)}"
-
-        _ ->
-          case Macro.decompose_call(fun) do
-            {_, _} = pair -> pair
-            _ -> raise ArgumentError, "invalid syntax in defdelegate #{Macro.to_string(fun)}"
-          end
+      case Macro.decompose_call(fun) do
+        {_, _} = pair -> pair
+        _ -> raise ArgumentError, "invalid syntax in defdelegate #{Macro.to_string(fun)}"
       end
 
     as = Keyword.get(opts, :as, name)
@@ -100,15 +64,7 @@ defmodule Kernel.Utils do
   @doc """
   Callback for defstruct.
   """
-  def defstruct(module, fields, bootstrapped?) do
-    {set, bag} = :elixir_module.data_tables(module)
-
-    if :ets.member(set, :__struct__) do
-      raise ArgumentError,
-            "defstruct has already been called for " <>
-              "#{Kernel.inspect(module)}, defstruct can only be called once per module"
-    end
-
+  def defstruct(module, fields) do
     case fields do
       fs when is_list(fs) ->
         :ok
@@ -120,7 +76,7 @@ defmodule Kernel.Utils do
     mapper = fn
       {key, val} when is_atom(key) ->
         try do
-          :elixir_quote.escape(val, false, :none)
+          Macro.escape(val)
         rescue
           e in [ArgumentError] ->
             raise ArgumentError, "invalid value for struct field #{key}, " <> Exception.message(e)
@@ -136,23 +92,7 @@ defmodule Kernel.Utils do
     end
 
     fields = :lists.map(mapper, fields)
-
-    enforce_keys =
-      case :ets.lookup(set, :enforce_keys) do
-        [{_, enforce_keys, _, _}] when is_list(enforce_keys) ->
-          :ets.update_element(set, :enforce_keys, {3, :used})
-          enforce_keys
-
-        [{_, enforce_key, _, _}] ->
-          :ets.update_element(set, :enforce_keys, {3, :used})
-          [enforce_key]
-
-        [] ->
-          []
-      end
-
-    # TODO: Make it raise on v2.0
-    warn_on_duplicate_struct_key(:lists.keysort(1, fields))
+    enforce_keys = List.wrap(Module.get_attribute(module, :enforce_keys))
 
     foreach = fn
       key when is_atom(key) ->
@@ -163,90 +103,18 @@ defmodule Kernel.Utils do
     end
 
     :lists.foreach(foreach, enforce_keys)
+
     struct = :maps.put(:__struct__, module, :maps.from_list(fields))
-
-    body =
-      case bootstrapped? do
-        true ->
-          case enforce_keys do
-            [] ->
-              quote do
-                Enum.reduce(kv, @__struct__, fn {key, val}, map ->
-                  %{map | key => val}
-                end)
-              end
-
-            _ ->
-              quote do
-                {map, keys} =
-                  Enum.reduce(kv, {@__struct__, unquote(enforce_keys)}, fn
-                    {key, val}, {map, keys} ->
-                      {%{map | key => val}, List.delete(keys, key)}
-                  end)
-
-                case keys do
-                  [] ->
-                    map
-
-                  _ ->
-                    raise ArgumentError,
-                          "the following keys must also be given when building " <>
-                            "struct #{inspect(__MODULE__)}: #{inspect(keys)}"
-                end
-              end
-          end
-
-        false ->
-          quote do
-            :lists.foldl(
-              fn {key, val}, acc -> %{acc | key => val} end,
-              @__struct__,
-              kv
-            )
-          end
-      end
-
-    case enforce_keys -- :maps.keys(struct) do
-      [] ->
-        # The __struct__ field is used for expansion and for loading remote structs
-        :ets.insert(set, {:__struct__, struct, nil, []})
-
-        # Store all field metadata to go into __info__(:struct)
-        mapper = fn {key, val} ->
-          %{field: key, default: val, required: :lists.member(key, enforce_keys)}
-        end
-
-        :ets.insert(set, {{:elixir, :struct}, :lists.map(mapper, fields)})
-        derive = :lists.map(fn {_, value} -> value end, :ets.take(bag, {:accumulate, :derive}))
-        {struct, :lists.reverse(derive), quote(do: kv), body}
-
-      error_keys ->
-        raise ArgumentError,
-              "@enforce_keys required keys (#{inspect(error_keys)}) that are not defined in defstruct: " <>
-                "#{inspect(fields)}"
-    end
-  end
-
-  defp warn_on_duplicate_struct_key([]) do
-    :ok
-  end
-
-  defp warn_on_duplicate_struct_key([{key, _} | [{key, _} | _] = rest]) do
-    IO.warn("duplicate key #{inspect(key)} found in struct")
-    warn_on_duplicate_struct_key(rest)
-  end
-
-  defp warn_on_duplicate_struct_key([_ | rest]) do
-    warn_on_duplicate_struct_key(rest)
+    {struct, enforce_keys, Module.get_attribute(module, :derive)}
   end
 
   @doc """
   Announcing callback for defstruct.
   """
   def announce_struct(module) do
-    case :erlang.get(:elixir_compiler_info) do
+    case :erlang.get(:elixir_compiler_pid) do
       :undefined -> :ok
-      {pid, _} -> send(pid, {:available, :struct, module})
+      pid -> send(pid, {:struct_available, module})
     end
   end
 
@@ -289,32 +157,27 @@ defmodule Kernel.Utils do
   macro.
 
   Secondly, if the expression is being used outside of a guard, we want to unquote
-  `value`, but only once, and then re-use the unquoted form throughout the expression.
+  `value`––but only once, and then re-use the unquoted form throughout the expression.
 
   This helper does exactly that: takes the AST for an expression and a list of
   variable references it should be aware of, and rewrites it into a new expression
   that checks for its presence in a guard, then unquotes the variable references as
   appropriate.
 
-  The following code
+  The resulting transformation looks something like this:
 
-      expression = quote do: is_integer(value) and rem(value, 2) == 0
-      variable_references = [value: Elixir]
-      Kernel.Utils.defguard(expression, variable_references) |> Macro.to_string() |> IO.puts()
+      > expression = quote do: is_integer(value) and rem(value, 2) == 0
+      > variable_references = [value: Elixir]
+      > Kernel.Utils.defguard(expression, variable_references) |> Macro.to_string |> IO.puts
 
-  would print a code similar to:
-
-      case Macro.Env.in_guard?(__CALLER__) do
-        true ->
-          quote do
-            is_integer(unquote(value)) and rem(unquote(value), 2) == 0
-          end
-
-        false ->
-          quote do
-            value = unquote(value)
-            is_integer(value) and rem(value, 2) == 0
-          end
+      case Macro.Env.in_guard? __CALLER__ do
+        true -> quote do
+          is_integer(unquote(value)) and rem(unquote(value), 2) == 0
+        end
+        false -> quote do
+          value = unquote(value)
+          is_integer(value) and rem(value, 2) == 0
+        end
       end
 
   """
@@ -326,7 +189,7 @@ defmodule Kernel.Utils do
   def defguard(args, expr, env) do
     {^args, vars} = extract_refs_from_args(args)
     env = :elixir_env.with_vars(%{env | context: :guard}, vars)
-    {expr, _, _} = :elixir_expand.expand(expr, :elixir_env.env_to_ex(env), env)
+    {expr, _scope} = :elixir_expand.expand(expr, env)
 
     quote do
       case Macro.Env.in_guard?(__CALLER__) do
@@ -362,36 +225,25 @@ defmodule Kernel.Utils do
 
   # Prefaces `guard` with unquoted versions of `refs`.
   defp unquote_refs_once(guard, refs) do
-    {guard, used_refs} =
-      Macro.postwalk(guard, %{}, fn
+    {_, used_refs} =
+      Macro.postwalk(guard, [], fn
         {ref, meta, context} = var, acc when is_atom(ref) and is_atom(context) ->
           pair = {ref, var_context(meta, context)}
 
-          case pair in refs do
-            true ->
-              case acc do
-                %{^pair => {new_var, _}} ->
-                  {new_var, acc}
-
-                %{} ->
-                  generated = String.to_atom("arg" <> Integer.to_string(map_size(acc) + 1))
-                  new_var = Macro.var(generated, Elixir)
-                  {new_var, Map.put(acc, pair, {new_var, var})}
-              end
-
-            false ->
-              {var, acc}
+          case pair in refs and pair not in acc do
+            true -> {var, [pair | acc]}
+            false -> {var, acc}
           end
 
         node, acc ->
           {node, acc}
       end)
 
-    all_used = for ref <- :lists.reverse(refs), used = :maps.get(ref, used_refs, nil), do: used
-    {vars, exprs} = :lists.unzip(all_used)
+    vars = for {ref, context} <- :lists.reverse(used_refs), do: context_to_var(ref, context)
+    exprs = for var <- vars, do: literal_unquote(var)
 
     quote do
-      {unquote_splicing(vars)} = {unquote_splicing(Enum.map(exprs, &literal_unquote/1))}
+      {unquote_splicing(vars)} = {unquote_splicing(exprs)}
       unquote(guard)
     end
   end
@@ -404,6 +256,9 @@ defmodule Kernel.Utils do
     {:unquote, [], List.wrap(ast)}
   end
 
+  defp context_to_var(ref, ctx) when is_atom(ctx), do: {ref, [], ctx}
+  defp context_to_var(ref, ctx) when is_integer(ctx), do: {ref, [counter: ctx], nil}
+
   defp var_context(meta, kind) do
     case :lists.keyfind(:counter, 1, meta) do
       {:counter, counter} -> counter

lib/elixir/lib/list/chars.ex

@@ -3,7 +3,7 @@ defprotocol List.Chars do
   The `List.Chars` protocol is responsible for
   converting a structure to a charlist (only if applicable).
 
-  The only function that must be implemented is
+  The only function required to be implemented is
   `to_charlist/1` which does the conversion.
 
   The `to_charlist/1` function automatically imported
@@ -17,6 +17,7 @@ defprotocol List.Chars do
   def to_charlist(term)
 
   @doc false
+  # TODO: Remove by 2.0
   @deprecated "Use List.Chars.to_charlist/1 instead"
   Kernel.def to_char_list(term) do
     __MODULE__.to_charlist(term)
@@ -24,8 +25,6 @@ defprotocol List.Chars do
 end
 
 defimpl List.Chars, for: Atom do
-  def to_charlist(nil), do: ''
-
   def to_charlist(atom), do: Atom.to_charlist(atom)
 end
 

lib/elixir/lib/macro/env.ex

@@ -21,97 +21,106 @@ defmodule Macro.Env do
 
   It contains the following fields:
 
-    * `context` - the context of the environment; it can be `nil`
-      (default context), `:guard` (inside a guard) or `:match` (inside a match)
-    * `context_modules` - a list of modules defined in the current context
-    * `file` - the current absolute file name as a binary
+    * `module` - the current module name
+    * `file` - the current file name as a binary
+    * `line` - the current line as an integer
     * `function` - a tuple as `{atom, integer}`, where the first
       element is the function name and the second its arity; returns
       `nil` if not inside a function
-    * `line` - the current line as an integer
-    * `module` - the current module name
+    * `context` - the context of the environment; it can be `nil`
+      (default context), inside a guard or inside a match
+    * `aliases` -  a list of two-element tuples, where the first
+      element is the aliased name and the second one the actual name
+    * `requires` - the list of required modules
+    * `functions` - a list of functions imported from each module
+    * `macros` - a list of macros imported from each module
+    * `macro_aliases` - a list of aliases defined inside the current macro
+    * `context_modules` - a list of modules defined in the current context
+    * `lexical_tracker` - PID of the lexical tracker which is responsible for
+      keeping user info
 
-  The following fields are private to Elixir's macro expansion mechanism and
-  must not be accessed directly:
+  The following fields pertain to variable handling and must not be accessed or
+  relied on. To get a list of all variables, see `vars/1`:
 
-    * `aliases`
-    * `functions`
-    * `macro_aliases`
-    * `macros`
-    * `lexical_tracker`
-    * `requires`
-    * `tracers`
-    * `versioned_vars`
+    * `current_vars`
+    * `unused_vars`
+    * `prematch_vars`
+    * `contextual_vars`
+
+  The following fields are deprecated and must not be accessed or relied on:
+
+    * `vars` - a list keeping all defined variables as `{var, context}`
 
   """
 
-  @type context :: :match | :guard | nil
-  @type context_modules :: [module]
+  @type name_arity :: {atom, arity}
   @type file :: binary
   @type line :: non_neg_integer
-  @type name_arity :: {atom, arity}
-  @type variable :: {atom, atom | term}
+  @type aliases :: [{module, module}]
+  @type macro_aliases :: [{module, {integer, module}}]
+  @type context :: :match | :guard | nil
+  @type requires :: [module]
+  @type functions :: [{module, [name_arity]}]
+  @type macros :: [{module, [name_arity]}]
+  @type context_modules :: [module]
+  @type lexical_tracker :: pid | nil
+  @type var :: {atom, atom | non_neg_integer}
 
-  @typep aliases :: [{module, module}]
-  @typep functions :: [{module, [name_arity]}]
-  @typep lexical_tracker :: pid | nil
-  @typep macro_aliases :: [{module, {term, module}}]
-  @typep macros :: [{module, [name_arity]}]
-  @typep requires :: [module]
-  @typep tracers :: [module]
-  @typep versioned_vars :: %{optional(variable) => var_version :: non_neg_integer}
+  @typep vars :: [var]
+  @typep var_type :: :term
+  @typep var_version :: non_neg_integer
+  @typep unused_vars :: %{{var, var_version} => non_neg_integer | false}
+  @typep current_vars :: %{var => {var_version, var_type}}
+  @typep prematch_vars :: current_vars | :warn | :raise | :pin | :apply
+  @typep contextual_vars :: [atom]
 
   @type t :: %{
           __struct__: __MODULE__,
-          aliases: aliases,
-          context: context,
-          context_modules: context_modules,
+          module: atom,
           file: file,
-          function: name_arity | nil,
-          functions: functions,
-          lexical_tracker: lexical_tracker,
           line: line,
-          macro_aliases: macro_aliases,
-          macros: macros,
-          module: module,
+          function: name_arity | nil,
+          context: context,
           requires: requires,
-          tracers: tracers,
-          versioned_vars: versioned_vars
+          aliases: aliases,
+          functions: functions,
+          macros: macros,
+          macro_aliases: aliases,
+          context_modules: context_modules,
+          vars: vars,
+          unused_vars: unused_vars,
+          current_vars: current_vars,
+          prematch_vars: prematch_vars,
+          lexical_tracker: lexical_tracker,
+          contextual_vars: contextual_vars
         }
 
-  fields = [
-    aliases: [],
-    context: nil,
-    context_modules: [],
-    file: "nofile",
-    function: nil,
-    functions: [],
-    lexical_tracker: nil,
-    line: 0,
-    macro_aliases: [],
-    macros: [],
-    module: nil,
-    requires: [],
-    tracers: [],
-    versioned_vars: %{}
-  ]
+  # TODO: Remove :vars field on v2.0
+  def __struct__ do
+    %{
+      __struct__: __MODULE__,
+      module: nil,
+      file: "nofile",
+      line: 0,
+      function: nil,
+      context: nil,
+      requires: [],
+      aliases: [],
+      functions: [],
+      macros: [],
+      macro_aliases: [],
+      context_modules: [],
+      vars: [],
+      unused_vars: %{},
+      current_vars: %{},
+      prematch_vars: :warn,
+      lexical_tracker: nil,
+      contextual_vars: []
+    }
+  end
 
-  # Define the __struct__ callbacks by hand for bootstrap reasons.
-  {struct, [], kv, body} = Kernel.Utils.defstruct(__MODULE__, fields, false)
-  def __struct__(), do: unquote(:elixir_quote.escape(struct, false, :none))
-  def __struct__(unquote(kv)), do: unquote(body)
-
-  @doc """
-  Prunes compile information from the environment.
-
-  This happens when the environment is captured at compilation
-  time, for example, in the module body, and then used to
-  evaluate code after the module has been defined.
-  """
-  @doc since: "1.14.0"
-  @spec prune_compile_info(t) :: t
-  def prune_compile_info(env) do
-    %{env | lexical_tracker: nil, tracers: []}
+  def __struct__(kv) do
+    Enum.reduce(kv, __struct__(), fn {k, v}, acc -> :maps.update(k, v, acc) end)
   end
 
   @doc """
@@ -123,33 +132,22 @@ defmodule Macro.Env do
   atom or an integer.
   """
   @doc since: "1.7.0"
-  @spec vars(t) :: [variable]
+  @spec vars(t) :: [var]
   def vars(env)
 
-  def vars(%{__struct__: Macro.Env, versioned_vars: vars}) do
-    Map.keys(vars)
+  def vars(%{__struct__: Macro.Env, current_vars: current_vars}) do
+    Map.keys(current_vars)
   end
 
   @doc """
   Checks if a variable belongs to the environment.
-
-  ## Examples
-
-      iex> x = 13
-      iex> x
-      13
-      iex> Macro.Env.has_var?(__ENV__, {:x, nil})
-      true
-      iex> Macro.Env.has_var?(__ENV__, {:unknown, nil})
-      false
-
   """
   @doc since: "1.7.0"
-  @spec has_var?(t, variable) :: boolean()
+  @spec has_var?(t, var) :: boolean()
   def has_var?(env, var)
 
-  def has_var?(%{__struct__: Macro.Env, versioned_vars: vars}, var) do
-    Map.has_key?(vars, var)
+  def has_var?(%{__struct__: Macro.Env, current_vars: current_vars}, var) do
+    Map.has_key?(current_vars, var)
   end
 
   @doc """
@@ -163,117 +161,16 @@ defmodule Macro.Env do
     [file: file, line: line]
   end
 
-  @doc """
-  Fetches the alias for the given atom.
-
-  Returns `{:ok, alias}` if the alias exists, `:error`
-  otherwise.
-
-  ## Examples
-
-      iex> alias Foo.Bar, as: Baz
-      iex> Baz
-      Foo.Bar
-      iex> Macro.Env.fetch_alias(__ENV__, :Baz)
-      {:ok, Foo.Bar}
-      iex> Macro.Env.fetch_alias(__ENV__, :Unknown)
-      :error
-
-  """
-  @doc since: "1.13.0"
-  @spec fetch_alias(t, atom) :: {:ok, atom} | :error
-  def fetch_alias(%{__struct__: Macro.Env, aliases: aliases}, atom) when is_atom(atom),
-    do: Keyword.fetch(aliases, :"Elixir.#{atom}")
-
-  @doc """
-  Fetches the macro alias for the given atom.
-
-  Returns `{:ok, macro_alias}` if the alias exists, `:error`
-  otherwise.
-
-  A macro alias is only used inside quoted expansion. See
-  `fetch_alias/2` for a more general example.
-  """
-  @doc since: "1.13.0"
-  @spec fetch_macro_alias(t, atom) :: {:ok, atom} | :error
-  def fetch_macro_alias(%{__struct__: Macro.Env, macro_aliases: aliases}, atom)
-      when is_atom(atom),
-      do: Keyword.fetch(aliases, :"Elixir.#{atom}")
-
-  @doc """
-  Returns the modules from which the given `{name, arity}` was
-  imported.
-
-  It returns a list of two element tuples in the shape of
-  `{:function | :macro, module}`. The elements in the list
-  are in no particular order and the order is not guaranteed.
-
-  ## Examples
-
-      iex> Macro.Env.lookup_import(__ENV__, {:duplicate, 2})
-      []
-      iex> import Tuple, only: [duplicate: 2], warn: false
-      iex> Macro.Env.lookup_import(__ENV__, {:duplicate, 2})
-      [{:function, Tuple}]
-      iex> import List, only: [duplicate: 2], warn: false
-      iex> Macro.Env.lookup_import(__ENV__, {:duplicate, 2})
-      [{:function, List}, {:function, Tuple}]
-
-      iex> Macro.Env.lookup_import(__ENV__, {:def, 1})
-      [{:macro, Kernel}]
-
-  """
-  @doc since: "1.13.0"
-  @spec lookup_import(t, name_arity) :: [{:function | :macro, module}]
-  def lookup_import(
-        %{__struct__: Macro.Env, functions: functions, macros: macros},
-        {name, arity} = pair
-      )
-      when is_atom(name) and is_integer(arity) do
-    f = for {mod, pairs} <- functions, :ordsets.is_element(pair, pairs), do: {:function, mod}
-    m = for {mod, pairs} <- macros, :ordsets.is_element(pair, pairs), do: {:macro, mod}
-    f ++ m
-  end
-
-  @doc """
-  Returns true if the given module has been required.
-
-  ## Examples
-
-      iex> Macro.Env.required?(__ENV__, Integer)
-      false
-      iex> require Integer
-      iex> Macro.Env.required?(__ENV__, Integer)
-      true
-
-      iex> Macro.Env.required?(__ENV__, Kernel)
-      true
-  """
-  @doc since: "1.13.0"
-  @spec required?(t, module) :: boolean
-  def required?(%{__struct__: Macro.Env, requires: requires}, mod) when is_atom(mod),
-    do: mod in requires
-
-  @doc """
-  Prepend a tracer to the list of tracers in the environment.
-
-  ## Examples
-
-      Macro.Env.prepend_tracer(__ENV__, MyCustomTracer)
-
-  """
-  @doc since: "1.13.0"
-  @spec prepend_tracer(t, module) :: t
-  def prepend_tracer(%{__struct__: Macro.Env, tracers: tracers} = env, tracer) do
-    %{env | tracers: [tracer | tracers]}
-  end
-
   @doc """
   Returns a `Macro.Env` in the match context.
   """
   @spec to_match(t) :: t
-  def to_match(%{__struct__: Macro.Env} = env) do
-    %{env | context: :match}
+  def to_match(%{__struct__: Macro.Env, context: :match} = env) do
+    env
+  end
+
+  def to_match(%{__struct__: Macro.Env, current_vars: vars} = env) do
+    %{env | context: :match, prematch_vars: vars}
   end
 
   @doc """