Unpack __block__ in type specs

Fixes #827

Author: yrashk

lib/elixir/lib/kernel/typespec.ex

@@ -559,6 +559,8 @@ defmodule Kernel.Typespec do
   end
 
   # Handle funs
+
+  defp typespec
   defp typespec({:->, meta, [{[{:fun, _, arguments}], return}]}, vars, caller) when is_list(arguments) do
     typespec({:->, meta, [{arguments, return}]}, vars, caller)
   end
@@ -608,6 +610,12 @@ defmodule Kernel.Typespec do
     { :type, line(meta), :tuple, args }
   end
 
+  # Handle blocks
+
+  defp typespec({:__block__, _meta, [arg]}, vars, caller) do
+    typespec(arg, vars, caller)
+  end
+
   # Handle variables or local calls
   defp typespec({name, meta, atom}, vars, caller) when is_atom(atom) do
     if List.member?(vars, name) do

lib/elixir/test/elixir/typespec_test.exs

@@ -318,6 +318,19 @@ defmodule Typespec.TypeTest do
     ] = Enum.sort(specs)
   end
 
+  test "block handling" do
+    spec =
+    test_module do
+      spec = @spec foo((() -> [ integer ])) :: integer
+      def foo(_), do: 1
+      spec
+    end
+    assert {{:foo,1},
+            {:type,_,:fun,[{:type,_,:product,[
+                     {:type,_,:fun,[{:type,_,:product,[]},{:type,_,:list,[{:type,_,:integer,[]}]}]}]},
+                     {:type,_,:integer,[]}]}} = spec
+  end
+
   # Conversion to AST
 
   test "type_to_ast" do