Improve ForwardRef equality checks

Author: hongweipeng

Lib/typing.py

@@ -524,8 +524,10 @@ def _evaluate(self, globalns, localns):
     def __eq__(self, other):
         if not isinstance(other, ForwardRef):
             return NotImplemented
-        return (self.__forward_arg__ == other.__forward_arg__ and
-                self.__forward_value__ == other.__forward_value__)
+        if self.__forward_evaluated__ and other.__forward_evaluated__:
+            return (self.__forward_arg__ == other.__forward_arg__ and
+                    self.__forward_value__ == other.__forward_value__)
+        return self.__forward_arg__ == other.__forward_arg__
 
     def __hash__(self):
         return hash((self.__forward_arg__, self.__forward_value__))

Misc/NEWS.d/next/Library/2019-08-31-12-57-17.bpo-37953.Fz3V7f.rst

@@ -0,0 +1 @@
+Improve ForwardRef equality checks. Patch by hongweipeng.