diff --git a/lib/elixir/src/elixir_code_server.erl b/lib/elixir/src/elixir_code_server.erl
index e5d7b560d2..31c19a8163 100644
--- a/lib/elixir/src/elixir_code_server.erl
+++ b/lib/elixir/src/elixir_code_server.erl
@@ -101,4 +101,4 @@ terminate(Reason, Config) ->
 code_change(_Old, Config, _Extra) ->
   { ok, Config }.
 
-module_tuple(I) -> { list_to_atom(lists:concat([elixir_compiler_, I])), I }.
\ No newline at end of file
+module_tuple(I) -> { list_to_atom("elixir_compiler_" ++ [I]), I }.
\ No newline at end of file