Do not add compile time deps on args to Application.compile_env/2, closes #11052

Author: josevalim

lib/elixir/lib/application.ex

@@ -507,11 +507,22 @@ defmodule Application do
       raise "Application.compile_env/3 cannot be called inside functions, only in the module body"
     end
 
+    key_or_path = expand_key_or_path(key_or_path, __CALLER__)
+
     quote do
       Application.__compile_env__(unquote(app), unquote(key_or_path), unquote(default), __ENV__)
     end
   end
 
+  defp expand_key_or_path({:__aliases__, _, _} = alias, env),
+    do: Macro.expand(alias, %{env | function: {:__info__, 1}})
+
+  defp expand_key_or_path(list, env) when is_list(list),
+    do: Enum.map(list, &expand_key_or_path(&1, env))
+
+  defp expand_key_or_path(other, _env),
+    do: other
+
   @doc false
   def __compile_env__(app, key_or_path, default, env) do
     case fetch_compile_env(app, key_or_path, env) do
@@ -533,6 +544,8 @@ defmodule Application do
       raise "Application.compile_env!/2 cannot be called inside functions, only in the module body"
     end
 
+    key_or_path = expand_key_or_path(key_or_path, __CALLER__)
+
     quote do
       Application.__compile_env__!(unquote(app), unquote(key_or_path), __ENV__)
     end

lib/elixir/test/elixir/kernel/lexical_tracker_test.exs

@@ -202,5 +202,20 @@ defmodule Kernel.LexicalTrackerTest do
       assert URI in exports
       refute URI in runtime
     end
+
+    test "compile_env! does not add a compile dependency" do
+      {{compile, exports, runtime, _}, _binding} =
+        Code.eval_string("""
+        defmodule Kernel.LexicalTrackerTest.CompileEnvStruct do
+          Application.compile_env(:elixir, URI)
+          Application.compile_env(:elixir, [:foo, URI, :bar])
+          Kernel.LexicalTracker.references(__ENV__.lexical_tracker)
+        end |> elem(3)
+        """)
+
+      refute URI in compile
+      refute URI in exports
+      assert URI in runtime
+    end
   end
 end