diff --git a/lib/elixir/test/elixir/kernel/binary_test.exs b/lib/elixir/test/elixir/kernel/binary_test.exs
index 29f12c364c..baaedeac14 100644
--- a/lib/elixir/test/elixir/kernel/binary_test.exs
+++ b/lib/elixir/test/elixir/kernel/binary_test.exs
@@ -167,9 +167,9 @@ bar """
   test :bitsyntax_translation do
     refb = "sample"
     sec_data = "another"
-    << size(refb) :: [size(1), big, signed, integer, unit(8)],
+    << byte_size(refb) :: [size(1), big, signed, integer, unit(8)],
        refb :: binary,
-       size(sec_data) :: [size(1), big, signed, integer, unit(16)],
+       byte_size(sec_data) :: [size(1), big, signed, integer, unit(16)],
        sec_data :: binary >>
   end
 
@@ -193,9 +193,9 @@ bar """
   test :bitsyntax_macro do
     refb = "sample"
     sec_data = "another"
-    << size(refb) :: refb_spec,
+    << byte_size(refb) :: refb_spec,
        refb :: binary,
-       size(sec_data) :: [size(1), signed_16],
+       byte_size(sec_data) :: [size(1), signed_16],
        sec_data :: binary >>
   end
 end
diff --git a/lib/mix/lib/mix/tasks/compile.ex b/lib/mix/lib/mix/tasks/compile.ex
index fe0e64d81c..d3faeaac58 100644
--- a/lib/mix/lib/mix/tasks/compile.ex
+++ b/lib/mix/lib/mix/tasks/compile.ex
@@ -36,7 +36,7 @@ defmodule Mix.Tasks.Compile do
     end
 
     max = Enum.reduce docs, 0, fn({task, _}, acc) ->
-      max(size(task), acc)
+      max(byte_size(task), acc)
     end
 
     sorted = Enum.sort(docs)
diff --git a/lib/mix/lib/mix/tasks/help.ex b/lib/mix/lib/mix/tasks/help.ex
index aa627a039b..fcc10d088b 100644
--- a/lib/mix/lib/mix/tasks/help.ex
+++ b/lib/mix/lib/mix/tasks/help.ex
@@ -47,7 +47,7 @@ defmodule Mix.Tasks.Help do
     end
 
     max = Enum.reduce docs, 0, fn({task, _}, acc) ->
-      max(size(task), acc)
+      max(byte_size(task), acc)
     end
 
     display_default_task_doc(max)
diff --git a/lib/mix/lib/mix/tasks/local.ex b/lib/mix/lib/mix/tasks/local.ex
index 7faf2055bb..a28a784735 100644
--- a/lib/mix/lib/mix/tasks/local.ex
+++ b/lib/mix/lib/mix/tasks/local.ex
@@ -17,7 +17,7 @@ defmodule Mix.Tasks.Local do
     end
 
     max = Enum.reduce docs, 0, fn({task, _}, acc) ->
-      max(size(task), acc)
+      max(byte_size(task), acc)
     end
 
     sorted = Enum.sort(docs)