1 files changed, 68 insertions, 0 deletions
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index 755ac03..70ae8e0 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -2722,6 +2722,74 @@ class TestSingleDispatch(unittest.TestCase):
         self.assertEqual(f(1), "types.UnionType")
         self.assertEqual(f(1.0), "types.UnionType")
 
+    def test_register_genericalias(self):
+        @functools.singledispatch
+        def f(arg):
+            return "default"
+
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(list[int], lambda arg: "types.GenericAlias")
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(typing.List[int], lambda arg: "typing.GenericAlias")
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(list[int] | str, lambda arg: "types.UnionTypes(types.GenericAlias)")
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(typing.List[float] | bytes, lambda arg: "typing.Union[typing.GenericAlias]")
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(typing.Any, lambda arg: "typing.Any")
+
+        self.assertEqual(f([1]), "default")
+        self.assertEqual(f([1.0]), "default")
+        self.assertEqual(f(""), "default")
+        self.assertEqual(f(b""), "default")
+
+    def test_register_genericalias_decorator(self):
+        @functools.singledispatch
+        def f(arg):
+            return "default"
+
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(list[int])
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(typing.List[int])
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(list[int] | str)
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(typing.List[int] | str)
+        with self.assertRaisesRegex(TypeError, "Invalid first argument to "):
+            f.register(typing.Any)
+
+    def test_register_genericalias_annotation(self):
+        @functools.singledispatch
+        def f(arg):
+            return "default"
+
+        with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
+            @f.register
+            def _(arg: list[int]):
+                return "types.GenericAlias"
+        with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
+            @f.register
+            def _(arg: typing.List[float]):
+                return "typing.GenericAlias"
+        with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
+            @f.register
+            def _(arg: list[int] | str):
+                return "types.UnionType(types.GenericAlias)"
+        with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
+            @f.register
+            def _(arg: typing.List[float] | bytes):
+                return "typing.Union[typing.GenericAlias]"
+        with self.assertRaisesRegex(TypeError, "Invalid annotation for 'arg'"):
+            @f.register
+            def _(arg: typing.Any):
+                return "typing.Any"
+
+        self.assertEqual(f([1]), "default")
+        self.assertEqual(f([1.0]), "default")
+        self.assertEqual(f(""), "default")
+        self.assertEqual(f(b""), "default")
+
 
 class CachedCostItem:
     _cost = 1