Improve __reduce__ signature accross stdlib (#7182)

stdlib/decimal.pyi

@@ -145,7 +145,7 @@ class Decimal:
     def rotate(self, other: _Decimal, context: Context | None = ...) -> Decimal: ...
     def scaleb(self, other: _Decimal, context: Context | None = ...) -> Decimal: ...
     def shift(self, other: _Decimal, context: Context | None = ...) -> Decimal: ...
-    def __reduce__(self) -> tuple[type[Decimal], tuple[str]]: ...
+    def __reduce__(self: Self) -> tuple[type[Self], tuple[str]]: ...
     def __copy__(self: Self) -> Self: ...
     def __deepcopy__(self: Self, __memo: Any) -> Self: ...
     def __format__(self, __specifier: str, __context: Context | None = ...) -> str: ...
@@ -183,7 +183,7 @@ class Context:
     # __setattr__() only allows to set a specific set of attributes,
     # already defined above.
     def __delattr__(self, __name: str) -> None: ...
-    def __reduce__(self) -> tuple[type[Context], tuple[Any, ...]]: ...
+    def __reduce__(self: Self) -> tuple[type[Self], tuple[Any, ...]]: ...
     def clear_flags(self) -> None: ...
     def clear_traps(self) -> None: ...
     def copy(self) -> Context: ...

stdlib/multiprocessing/shared_memory.pyi

@@ -1,10 +1,10 @@
 import sys
+from _typeshed import Self
 from typing import Any, Generic, Iterable, TypeVar
 
 if sys.version_info >= (3, 9):
     from types import GenericAlias
 
-_S = TypeVar("_S")
 _SLT = TypeVar("_SLT", int, float, bool, str, bytes, None)
 
 if sys.version_info >= (3, 8):
@@ -24,7 +24,7 @@ if sys.version_info >= (3, 8):
         def __init__(self, sequence: Iterable[_SLT] | None = ..., *, name: str | None = ...) -> None: ...
         def __getitem__(self, position: int) -> _SLT: ...
         def __setitem__(self, position: int, value: _SLT) -> None: ...
-        def __reduce__(self: _S) -> tuple[_S, tuple[_SLT, ...]]: ...
+        def __reduce__(self: Self) -> tuple[Self, tuple[_SLT, ...]]: ...
         def __len__(self) -> int: ...
         @property
         def format(self) -> str: ...

stdlib/multiprocessing/sharedctypes.pyi

@@ -76,7 +76,7 @@ class SynchronizedBase(Generic[_CT]):
     acquire: _AcquireFunc
     release: Callable[[], None]
     def __init__(self, obj: Any, lock: _LockLike | None = ..., ctx: Any | None = ...) -> None: ...
-    def __reduce__(self) -> tuple[Callable[..., Any], tuple[Any, _LockLike]]: ...
+    def __reduce__(self) -> tuple[Callable[[Any, _LockLike], SynchronizedBase[Any]], tuple[Any, _LockLike]]: ...
     def get_obj(self) -> _CT: ...
     def get_lock(self) -> _LockLike: ...
     def __enter__(self) -> bool: ...

stdlib/plistlib.pyi

@@ -1,4 +1,5 @@
 import sys
+from _typeshed import Self
 from datetime import datetime
 from enum import Enum
 from typing import IO, Any, Mapping, MutableMapping
@@ -68,7 +69,7 @@ if sys.version_info >= (3, 8):
         data: int
         def __init__(self, data: int) -> None: ...
         def __index__(self) -> int: ...
-        def __reduce__(self) -> Any: ...
+        def __reduce__(self: Self) -> tuple[type[Self], tuple[int]]: ...
         def __hash__(self) -> int: ...
 
 class InvalidFileException(ValueError):