Added __class_getitem__ (#4695)

Resolves #4682

Co-authored-by: hauntsaninja <>

stdlib/2and3/_weakref.pyi

@@ -1,6 +1,9 @@
 import sys
 from typing import Any, Callable, Generic, Optional, TypeVar, overload
 
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+
 _C = TypeVar("_C", bound=Callable[..., Any])
 _T = TypeVar("_T")
 
@@ -16,6 +19,8 @@ class ReferenceType(Generic[_T]):
     def __init__(self, o: _T, callback: Optional[Callable[[ReferenceType[_T]], Any]] = ...) -> None: ...
     def __call__(self) -> Optional[_T]: ...
     def __hash__(self) -> int: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
 
 ref = ReferenceType
 

stdlib/2and3/_weakrefset.pyi

@@ -1,5 +1,9 @@
+import sys
 from typing import Any, Generic, Iterable, Iterator, MutableSet, Optional, TypeVar, Union
 
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+
 _S = TypeVar("_S")
 _T = TypeVar("_T")
 _SelfT = TypeVar("_SelfT", bound=WeakSet[Any])
@@ -39,3 +43,5 @@ class WeakSet(MutableSet[_T], Generic[_T]):
     def union(self, other: Iterable[_S]) -> WeakSet[Union[_S, _T]]: ...
     def __or__(self, other: Iterable[_S]) -> WeakSet[Union[_S, _T]]: ...
     def isdisjoint(self, other: Iterable[_T]) -> bool: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...

stdlib/2and3/ctypes/__init__.pyi

@@ -21,6 +21,9 @@ from typing import (
     overload,
 )
 
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+
 _T = TypeVar("_T")
 _DLLT = TypeVar("_DLLT", bound=CDLL)
 _CT = TypeVar("_CT", bound=_CData)
@@ -58,6 +61,8 @@ class LibraryLoader(Generic[_DLLT]):
     def __getattr__(self, name: str) -> _DLLT: ...
     def __getitem__(self, name: str) -> _DLLT: ...
     def LoadLibrary(self, name: str) -> _DLLT: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
 
 cdll: LibraryLoader[CDLL] = ...
 if sys.platform == "win32":
@@ -302,3 +307,5 @@ class Array(Generic[_CT], _CData):
     # Can't inherit from Sized because the metaclass conflict between
     # Sized and _CData prevents using _CDataMeta.
     def __len__(self) -> int: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...

stdlib/2and3/difflib.pyi

@@ -19,6 +19,9 @@ from typing import (
     overload,
 )
 
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+
 _T = TypeVar("_T")
 
 if sys.version_info >= (3,):
@@ -53,6 +56,8 @@ class SequenceMatcher(Generic[_T]):
     def ratio(self) -> float: ...
     def quick_ratio(self) -> float: ...
     def real_quick_ratio(self) -> float: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
 
 # mypy thinks the signatures of the overloads overlap, but the types still work fine
 @overload

stdlib/2and3/filecmp.pyi

@@ -1,10 +1,13 @@
 # Stubs for filecmp (Python 2/3)
 import sys
-from typing import AnyStr, Callable, Dict, Generic, Iterable, List, Optional, Sequence, Text, Tuple, Union
+from typing import Any, AnyStr, Callable, Dict, Generic, Iterable, List, Optional, Sequence, Text, Tuple, Union
 
 if sys.version_info >= (3, 6):
     from os import PathLike
 
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+
 DEFAULT_IGNORES: List[str]
 
 if sys.version_info >= (3, 6):
@@ -41,7 +44,6 @@ class dircmp(Generic[AnyStr]):
     right: AnyStr
     hide: Sequence[AnyStr]
     ignore: Sequence[AnyStr]
-
     # These properties are created at runtime by __getattr__
     subdirs: Dict[AnyStr, dircmp[AnyStr]]
     same_files: List[AnyStr]
@@ -65,6 +67,8 @@ class dircmp(Generic[AnyStr]):
     def phase3(self) -> None: ...
     def phase4(self) -> None: ...
     def phase4_closure(self) -> None: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
 
 if sys.version_info >= (3,):
     def clear_cache() -> None: ...

stdlib/2and3/mailbox.pyi

@@ -1,4 +1,5 @@
 import email.message
+import sys
 from _typeshed import AnyPath
 from types import TracebackType
 from typing import (
@@ -24,6 +25,9 @@ from typing import (
 )
 from typing_extensions import Literal
 
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+
 _T = TypeVar("_T")
 _MessageType = TypeVar("_MessageType", bound=Message)
 _MessageData = Union[email.message.Message, bytes, str, IO[str], IO[bytes]]
@@ -76,6 +80,8 @@ class Mailbox(Generic[_MessageType]):
     def lock(self) -> None: ...
     def unlock(self) -> None: ...
     def close(self) -> None: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
 
 class Maildir(Mailbox[MaildirMessage]):
 
@@ -188,6 +194,8 @@ class _ProxyFile(Generic[AnyStr]):
     def flush(self) -> None: ...
     @property
     def closed(self) -> bool: ...
+    if sys.version_info >= (3, 9):
+        def __class_getitem__(cls, item: Any) -> GenericAlias: ...
 
 class _PartialFile(_ProxyFile[AnyStr]):
     def __init__(self, f: IO[AnyStr], start: Optional[int] = ..., stop: Optional[int] = ...) -> None: ...