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author | Serhiy Storchaka <storchaka@gmail.com> | 2020-05-10 13:39:40 +0300 |
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committer | GitHub <noreply@github.com> | 2020-05-10 13:39:40 +0300 |
commit | 0122d48681b1df27015cf396559fb283ba364d6d (patch) | |
tree | 3a1af9bb5c8a31fa65dd8ca3bf5395506a1443bf | |
parent | 86a93fddf72a2711aca99afa0c5374c8d6b4a321 (diff) | |
download | cpython-git-0122d48681b1df27015cf396559fb283ba364d6d.tar.gz |
bpo-40397: Fix subscription of nested generic alias without parameters. (GH-20021)
-rw-r--r-- | Lib/test/test_typing.py | 13 | ||||
-rw-r--r-- | Lib/typing.py | 6 |
2 files changed, 16 insertions, 3 deletions
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index 21bc7c81f2..f429e883b5 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -10,7 +10,7 @@ from typing import Any, NoReturn from typing import TypeVar, AnyStr from typing import T, KT, VT # Not in __all__. from typing import Union, Optional, Literal -from typing import Tuple, List, MutableMapping +from typing import Tuple, List, Dict, MutableMapping from typing import Callable from typing import Generic, ClassVar, Final, final, Protocol from typing import cast, runtime_checkable @@ -3173,6 +3173,17 @@ class CollectionsAbcTests(BaseTestCase): def test_dict(self): self.assertIsSubclass(dict, typing.Dict) + def test_dict_subscribe(self): + K = TypeVar('K') + V = TypeVar('V') + self.assertEqual(Dict[K, V][str, int], Dict[str, int]) + self.assertEqual(Dict[K, int][str], Dict[str, int]) + self.assertEqual(Dict[str, V][int], Dict[str, int]) + self.assertEqual(Dict[K, List[V]][str, int], Dict[str, List[int]]) + self.assertEqual(Dict[K, List[int]][str], Dict[str, List[int]]) + self.assertEqual(Dict[K, list[V]][str, int], Dict[str, list[int]]) + self.assertEqual(Dict[K, list[int]][str], Dict[str, list[int]]) + def test_no_list_instantiation(self): with self.assertRaises(TypeError): typing.List() diff --git a/Lib/typing.py b/Lib/typing.py index e31fc99e02..b5ba38e07c 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -702,8 +702,10 @@ class _GenericAlias(_BaseGenericAlias, _root=True): if isinstance(arg, TypeVar): arg = subst[arg] elif isinstance(arg, (_GenericAlias, GenericAlias)): - subargs = tuple(subst[x] for x in arg.__parameters__) - arg = arg[subargs] + subparams = arg.__parameters__ + if subparams: + subargs = tuple(subst[x] for x in subparams) + arg = arg[subargs] new_args.append(arg) return self.copy_with(tuple(new_args)) |