pythongh-133925: Make typing._UnionGenericAlias hashable (python#133929)

Author: JelleZijlstra

Lib/test/test_typing.py

@@ -10668,6 +10668,9 @@ def test_eq(self):
         with self.assertWarns(DeprecationWarning):
             self.assertNotEqual(int, typing._UnionGenericAlias)
 
+    def test_hashable(self):
+        self.assertEqual(hash(typing._UnionGenericAlias), hash(Union))
+
 
 def load_tests(loader, tests, pattern):
     import doctest

Lib/typing.py

@@ -1649,6 +1649,9 @@ def __eq__(self, other):
             return True
         return NotImplemented
 
+    def __hash__(self):
+        return hash(Union)
+
 
 class _UnionGenericAlias(metaclass=_UnionGenericAliasMeta):
     """Compatibility hack.

Misc/NEWS.d/next/Library/2025-05-12-06-52-10.gh-issue-133925.elInBY.rst

@@ -0,0 +1 @@
+Make the private class ``typing._UnionGenericAlias`` hashable.