diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/_collections_abc.py | 12 | ||||
| -rw-r--r-- | Lib/test/test_genericalias.py | 6 |
2 files changed, 17 insertions, 1 deletions
diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py index 7c3faa6..e4eac79 100644 --- a/Lib/_collections_abc.py +++ b/Lib/_collections_abc.py @@ -434,7 +434,7 @@ class _CallableGenericAlias(GenericAlias): raise TypeError( "Callable must be used as Callable[[arg, ...], result].") t_args, t_result = args - if isinstance(t_args, list): + if isinstance(t_args, (list, tuple)): ga_args = tuple(t_args) + (t_result,) # This relaxes what t_args can be on purpose to allow things like # PEP 612 ParamSpec. Responsibility for whether a user is using @@ -456,6 +456,16 @@ class _CallableGenericAlias(GenericAlias): args = list(args[:-1]), args[-1] return _CallableGenericAlias, (Callable, args) + def __getitem__(self, item): + # Called during TypeVar substitution, returns the custom subclass + # rather than the default types.GenericAlias object. + ga = super().__getitem__(item) + args = ga.__args__ + t_result = args[-1] + t_args = args[:-1] + args = (t_args, t_result) + return _CallableGenericAlias(Callable, args) + def _type_repr(obj): """Return the repr() of an object, special-casing types (internal helper). diff --git a/Lib/test/test_genericalias.py b/Lib/test/test_genericalias.py index 5de13fe..ccf40b1 100644 --- a/Lib/test/test_genericalias.py +++ b/Lib/test/test_genericalias.py @@ -347,6 +347,12 @@ class BaseTest(unittest.TestCase): self.assertEqual(C2[int, float, str], Callable[[int, float], str]) self.assertEqual(C3[int], Callable[..., int]) + # multi chaining + C4 = C2[int, V, str] + self.assertEqual(repr(C4).split(".")[-1], "Callable[[int, ~V], str]") + self.assertEqual(repr(C4[dict]).split(".")[-1], "Callable[[int, dict], str]") + self.assertEqual(C4[dict], Callable[[int, dict], str]) + with self.subTest("Testing type erasure"): class C1(Callable): def __call__(self): |