Only expand __ENV__.call if it is a known function

Author: José Valim

lib/elixir/lib/macro.ex

@@ -658,8 +658,13 @@ defmodule Macro do
 
  defp do_expand_once({ :__ENV__, _, atom }, env) when is_atom(atom),
  do: { { :{}, [], tuple_to_list(env) }, true }
- defp do_expand_once({ { :., _, [{ :__ENV__, _, atom }, field] }, _, [] }, env) when is_atom(atom) and is_atom(field),
- do: { apply(env, field, []), true }
+ defp do_expand_once({ { :., _, [{ :__ENV__, _, atom }, field] }, _, [] } = original, env) when
+ is_atom(atom) and is_atom(field) do
+ case :erlang.function_exported(Macro.Env, field, 1) do
+ true -> { apply(env, field, []), true }
+ false -> { original, false }
+ end
+ end
 
  # Expand possible macro import invocation
  defp do_expand_once({ atom, meta, context } = original, env)

lib/elixir/src/elixir_code_server.erl

@@ -27,6 +27,7 @@ start_link() ->
  gen_server:start_link({local, ?MODULE}, ?MODULE, ok, []).
 
 init(ok) ->
+ code:ensure_loaded('Elixir.Macro.Env'),
  code:ensure_loaded('Elixir.Module.LocalsTracker'),
  code:ensure_loaded('Elixir.Kernel.LexicalTracker'),
  { ok, #elixir_code_server{} }.

lib/elixir/src/elixir_exp.erl

@@ -132,8 +132,12 @@ expand({ '__CALLER__', _, Atom } = Caller, E) when is_atom(Atom) ->
 expand({ '__ENV__', Meta, Atom }, E) when is_atom(Atom) ->
  Env = elixir_env:env_to_ex({ ?line(Meta), E }),
  { { '{}', [], tuple_to_list(Env) }, E };
-expand({ { '.', _, [{ '__ENV__', Meta, Atom }, Field] }, _, [] }, E) when is_atom(Atom), is_atom(Field) ->
- { (elixir_env:env_to_ex({ ?line(Meta), E })):Field(), E };
+expand({ { '.', DotMeta, [{ '__ENV__', Meta, Atom }, Field] }, CallMeta, [] }, E) when is_atom(Atom), is_atom(Field) ->
+ Env = elixir_env:env_to_ex({ ?line(Meta), E }),
+ case erlang:function_exported('Elixir.Macro.Env', Field, 1) of
+ true -> { Env:Field(), E };
+ false -> { { { '.', DotMeta, [{ '{}', [], tuple_to_list(Env) }, Field] }, CallMeta, [] }, E }
+ end;
 
 %% Quote
 

lib/elixir/test/elixir/kernel/expansion_test.exs

@@ -104,7 +104,10 @@ defmodule Kernel.ExpansionTest do
  end
 
  test "__ENV__.accessor" do
- assert expand(quote(do: __ENV__.file)) == __ENV__.file
+ env = __ENV__
+ assert expand_env(quote(do: __ENV__.file), env) == { __ENV__.file, env }
+ assert expand_env(quote(do: __ENV__.unknown), env) ==
+ { quote(do: unquote({ :{}, [], tuple_to_list(env.line(0)) }).unknown), env }
  end
 
  ## Super

lib/elixir/test/elixir/macro_test.exs

@@ -150,6 +150,13 @@ defmodule MacroTest do
  assert Macro.expand_once(quote(do: :foo), __ENV__) == :foo
  end
 
+ test :expand_once_env do
+ env = __ENV__
+ assert Macro.expand_once(quote(do: __ENV__), env) == { :{}, [], tuple_to_list(env) }
+ assert Macro.expand_once(quote(do: __ENV__.file), env) == env.file
+ assert Macro.expand_once(quote(do: __ENV__.unkown), env) == quote(do: __ENV__.unkown)
+ end
+
  defmacro local_macro do
  :local_macro
  end