Typespecs: show expanded module name on inexistent struct field error (#11353)

Closes #11352.

Author: v0idpwn

lib/elixir/lib/kernel/typespec.ex

@@ -575,7 +575,7 @@ defmodule Kernel.Typespec do
       unless Keyword.has_key?(struct, field) do
         compile_error(
           caller,
-          "undefined field #{inspect(field)} on struct #{Macro.to_string(name)}"
+          "undefined field #{inspect(field)} on struct #{inspect(module)}"
         )
       end
     end

lib/elixir/test/elixir/typespec_test.exs

@@ -521,12 +521,23 @@ defmodule TypespecTest do
     end
 
     test "@type with a struct with undefined field" do
-      assert_raise CompileError, ~r"undefined field :no_field on struct TypespecSample", fn ->
-        test_module do
-          defstruct [:hello, :eric]
-          @type my_type :: %TypespecSample{no_field: :world}
-        end
-      end
+      assert_raise CompileError,
+                   ~r"undefined field :no_field on struct TypespecTest.TypespecSample",
+                   fn ->
+                     test_module do
+                       defstruct [:hello, :eric]
+                       @type my_type :: %TypespecSample{no_field: :world}
+                     end
+                   end
+
+      assert_raise CompileError,
+                   ~r"undefined field :no_field on struct TypespecTest.TypespecSample",
+                   fn ->
+                     test_module do
+                       defstruct [:hello, :eric]
+                       @type my_type :: %__MODULE__{no_field: :world}
+                     end
+                   end
     end
 
     test "@type when overriding Elixir built-in" do