Fix @macrocallback spec translation

Signed-off-by: James Fish <james@fishcakez.com>

Author: fishcakez

lib/elixir/lib/kernel/typespec.ex

@@ -448,7 +448,7 @@ defmodule Kernel.Typespec do
   defp translate_spec(kind, meta, name, args, return, guard, caller) when is_atom(args),
     do: translate_spec(kind, meta, name, [], return, guard, caller)
   defp translate_spec(:macrocallback, meta, name, args, return, guard, caller),
-    do: translate_spec(:callback, meta, :"MACRO-#{name}", [quote(do: env :: Macro.Env.t) | args], return, guard, caller)
+    do: translate_spec(:callback, meta, :"MACRO-#{name}", macro_args(args), return, guard, caller)
   defp translate_spec(kind, meta, name, args, return, guard, caller) do
     ensure_no_defaults!(args)
 
@@ -470,6 +470,10 @@ defmodule Kernel.Typespec do
     {{kind, {name, arity}, spec}, caller.line}
   end
 
+  defp macro_args(args) do
+    [quote(do: {line :: Macro.Env.line, env :: Macro.Env.t}) | args]
+  end
+
   defp ensure_no_defaults!(args) do
     :lists.foreach fn
       {:::, _, [left, right]} ->

lib/elixir/test/elixir/fixtures/dialyzer/macrocallback.ex

@@ -0,0 +1,11 @@
+defmodule Dialyzer.Macrocallback do
+  @macrocallback required(atom) :: Macro.t
+  @macrocallback optional(atom) :: Macro.t
+  @optional_callbacks [optional: 1]
+end
+
+defmodule Dialyzer.Macrocallback.Impl do
+  @behaviour Dialyzer.Macrocallback
+  defmacro required(var), do: Macro.expand(var, __CALLER__)
+  defmacro optional(var), do: Macro.expand(var, __CALLER__)
+end

lib/elixir/test/elixir/kernel/dialyzer_test.exs

@@ -16,8 +16,14 @@ defmodule Kernel.DialyzerTest do
       |> Path.join("base_plt")
       |> String.to_charlist()
 
-    # Add a few key elixir modules for types
-    files = Enum.map([Kernel, String, Keyword, Exception], &:code.which/1)
+    # Some OSs (like Windows) do not provide the HOME environment variable.
+    unless System.get_env("HOME") do
+      System.put_env("HOME", System.user_home())
+    end
+
+    # Add a few key elixir modules for types and macro functions
+    mods = [Kernel, String, Keyword, Exception, Macro, Macro.Env, :elixir_env]
+    files = Enum.map(mods, &:code.which/1)
     :dialyzer.run([analysis_type: :plt_build, output_plt: plt,
                    apps: [:erts], files: files])
 
@@ -64,6 +70,12 @@ defmodule Kernel.DialyzerTest do
     assert_dialyze_no_warnings! context
   end
 
+  test "no warnings on macrocallback", context do
+    copy_beam! context, Dialyzer.Macrocallback
+    copy_beam! context, Dialyzer.Macrocallback.Impl
+    assert_dialyze_no_warnings! context
+  end
+
   defp copy_beam!(context, module) do
     name = "#{module}.beam"
     File.cp! Path.join(context[:base_dir], name),