Always use _typeshed.Self, where applicable

stdlib/_typeshed/__init__.pyi

@@ -215,4 +215,4 @@ class structseq(Generic[_T_co]):
     # The second parameter will accept a dict of any kind without raising an exception,
     # but only has any meaning if you supply it a dict where the keys are strings.
     # https://github.com/python/typeshed/pull/6560#discussion_r767149830
-    def __new__(cls: type[_T], sequence: Iterable[_T_co], dict: dict[str, Any] = ...) -> _T: ...
+    def __new__(cls: type[Self], sequence: Iterable[_T_co], dict: dict[str, Any] = ...) -> Self: ...

stdlib/_weakrefset.pyi

@@ -1,34 +1,34 @@
 import sys
+from _typeshed import Self
 from typing import Any, Generic, Iterable, Iterator, MutableSet, TypeVar
 
 if sys.version_info >= (3, 9):
     from types import GenericAlias
 
 _S = TypeVar("_S")
 _T = TypeVar("_T")
-_SelfT = TypeVar("_SelfT", bound=WeakSet[Any])
 
 class WeakSet(MutableSet[_T], Generic[_T]):
     def __init__(self, data: Iterable[_T] | None = ...) -> None: ...
     def add(self, item: _T) -> None: ...
     def clear(self) -> None: ...
     def discard(self, item: _T) -> None: ...
-    def copy(self: _SelfT) -> _SelfT: ...
+    def copy(self: Self) -> Self: ...
     def pop(self) -> _T: ...
     def remove(self, item: _T) -> None: ...
     def update(self, other: Iterable[_T]) -> None: ...
     def __contains__(self, item: object) -> bool: ...
     def __len__(self) -> int: ...
     def __iter__(self) -> Iterator[_T]: ...
     def __ior__(self, other: Iterable[_S]) -> WeakSet[_S | _T]: ...
-    def difference(self: _SelfT, other: Iterable[_T]) -> _SelfT: ...
-    def __sub__(self: _SelfT, other: Iterable[_T]) -> _SelfT: ...
+    def difference(self: Self, other: Iterable[_T]) -> Self: ...
+    def __sub__(self: Self, other: Iterable[_T]) -> Self: ...
     def difference_update(self, other: Iterable[_T]) -> None: ...
-    def __isub__(self: _SelfT, other: Iterable[_T]) -> _SelfT: ...
-    def intersection(self: _SelfT, other: Iterable[_T]) -> _SelfT: ...
-    def __and__(self: _SelfT, other: Iterable[_T]) -> _SelfT: ...
+    def __isub__(self: Self, other: Iterable[_T]) -> Self: ...
+    def intersection(self: Self, other: Iterable[_T]) -> Self: ...
+    def __and__(self: Self, other: Iterable[_T]) -> Self: ...
     def intersection_update(self, other: Iterable[_T]) -> None: ...
-    def __iand__(self: _SelfT, other: Iterable[_T]) -> _SelfT: ...
+    def __iand__(self: Self, other: Iterable[_T]) -> Self: ...
     def issubset(self, other: Iterable[_T]) -> bool: ...
     def __le__(self, other: Iterable[_T]) -> bool: ...
     def __lt__(self, other: Iterable[_T]) -> bool: ...

stdlib/builtins.pyi

@@ -70,7 +70,6 @@ _T3 = TypeVar("_T3")
 _T4 = TypeVar("_T4")
 _T5 = TypeVar("_T5")
 _TT = TypeVar("_TT", bound="type")
-_TBE = TypeVar("_TBE", bound="BaseException")
 _R = TypeVar("_R")  # Return-type TypeVar
 _SupportsNextT = TypeVar("_SupportsNextT", bound=SupportsNext[Any], covariant=True)
 _SupportsAnextT = TypeVar("_SupportsAnextT", bound=SupportsAnext[Any], covariant=True)
@@ -92,7 +91,7 @@ class object:
     @__class__.setter
     def __class__(self, __type: type[object]) -> None: ...  # type: ignore # noqa: F811
     def __init__(self) -> None: ...
-    def __new__(cls: type[_T]) -> _T: ...
+    def __new__(cls: type[Self]) -> Self: ...
     def __setattr__(self, __name: str, __value: Any) -> None: ...
     def __eq__(self, __o: object) -> bool: ...
     def __ne__(self, __o: object) -> bool: ...
@@ -117,7 +116,7 @@ class staticmethod(Generic[_R]):  # Special, only valid as a decorator.
     __func__: Callable[..., _R]
     __isabstractmethod__: bool
     def __init__(self: staticmethod[_R], __f: Callable[..., _R]) -> None: ...
-    def __new__(cls: type[_T], *args: Any, **kwargs: Any) -> _T: ...
+    def __new__(cls: type[Self], *args: Any, **kwargs: Any) -> Self: ...
     def __get__(self, __obj: _T, __type: type[_T] | None = ...) -> Callable[..., _R]: ...
     if sys.version_info >= (3, 10):
         __name__: str
@@ -129,7 +128,7 @@ class classmethod(Generic[_R]):  # Special, only valid as a decorator.
     __func__: Callable[..., _R]
     __isabstractmethod__: bool
     def __init__(self: classmethod[_R], __f: Callable[..., _R]) -> None: ...
-    def __new__(cls: type[_T], *args: Any, **kwargs: Any) -> _T: ...
+    def __new__(cls: type[Self], *args: Any, **kwargs: Any) -> Self: ...
     def __get__(self, __obj: _T, __type: type[_T] | None = ...) -> Callable[..., _R]: ...
     if sys.version_info >= (3, 10):
         __name__: str
@@ -157,7 +156,7 @@ class type:
     @overload
     def __new__(cls, __o: object) -> type: ...
     @overload
-    def __new__(cls: type[_TT], __name: str, __bases: tuple[type, ...], __namespace: dict[str, Any], **kwds: Any) -> _TT: ...
+    def __new__(cls: type[Self], __name: str, __bases: tuple[type, ...], __namespace: dict[str, Any], **kwds: Any) -> Self: ...
     def __call__(self, *args: Any, **kwds: Any) -> Any: ...
     def __subclasses__(self: _TT) -> list[_TT]: ...
     # Note: the documentation doesn't specify what the return type is, the standard
@@ -184,9 +183,9 @@ _NegativeInteger = Literal[-1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -1
 
 class int:
     @overload
-    def __new__(cls: type[_T], __x: str | bytes | SupportsInt | SupportsIndex | SupportsTrunc = ...) -> _T: ...
+    def __new__(cls: type[Self], __x: str | bytes | SupportsInt | SupportsIndex | SupportsTrunc = ...) -> Self: ...
     @overload
-    def __new__(cls: type[_T], __x: str | bytes | bytearray, base: SupportsIndex) -> _T: ...
+    def __new__(cls: type[Self], __x: str | bytes | bytearray, base: SupportsIndex) -> Self: ...
     if sys.version_info >= (3, 8):
         def as_integer_ratio(self) -> tuple[int, Literal[1]]: ...
     @property
@@ -269,7 +268,7 @@ class int:
     def __index__(self) -> int: ...
 
 class float:
-    def __new__(cls: type[_T], x: SupportsFloat | SupportsIndex | str | bytes | bytearray = ...) -> _T: ...
+    def __new__(cls: type[Self], x: SupportsFloat | SupportsIndex | str | bytes | bytearray = ...) -> Self: ...
     def as_integer_ratio(self) -> tuple[int, int]: ...
     def hex(self) -> str: ...
     def is_integer(self) -> bool: ...
@@ -326,9 +325,9 @@ class float:
 
 class complex:
     @overload
-    def __new__(cls: type[_T], real: float = ..., imag: float = ...) -> _T: ...
+    def __new__(cls: type[Self], real: float = ..., imag: float = ...) -> Self: ...
     @overload
-    def __new__(cls: type[_T], real: str | SupportsComplex | SupportsIndex | complex) -> _T: ...
+    def __new__(cls: type[Self], real: str | SupportsComplex | SupportsIndex | complex) -> Self: ...
     @property
     def real(self) -> float: ...
     @property
@@ -359,9 +358,9 @@ class _FormatMapMapping(Protocol):
 
 class str(Sequence[str]):
     @overload
-    def __new__(cls: type[_T], object: object = ...) -> _T: ...
+    def __new__(cls: type[Self], object: object = ...) -> Self: ...
     @overload
-    def __new__(cls: type[_T], o: bytes, encoding: str = ..., errors: str = ...) -> _T: ...
+    def __new__(cls: type[Self], o: bytes, encoding: str = ..., errors: str = ...) -> Self: ...
     def capitalize(self) -> str: ...
     def casefold(self) -> str: ...
     def center(self, __width: SupportsIndex, __fillchar: str = ...) -> str: ...
@@ -443,15 +442,15 @@ class str(Sequence[str]):
 
 class bytes(ByteString):
     @overload
-    def __new__(cls: type[_T], __ints: Iterable[SupportsIndex]) -> _T: ...
+    def __new__(cls: type[Self], __ints: Iterable[SupportsIndex]) -> Self: ...
     @overload
-    def __new__(cls: type[_T], __string: str, encoding: str, errors: str = ...) -> _T: ...
+    def __new__(cls: type[Self], __string: str, encoding: str, errors: str = ...) -> Self: ...
     @overload
-    def __new__(cls: type[_T], __length: SupportsIndex) -> _T: ...
+    def __new__(cls: type[Self], __length: SupportsIndex) -> Self: ...
     @overload
-    def __new__(cls: type[_T]) -> _T: ...
+    def __new__(cls: type[Self]) -> Self: ...
     @overload
-    def __new__(cls: type[_T], __o: SupportsBytes) -> _T: ...
+    def __new__(cls: type[Self], __o: SupportsBytes) -> Self: ...
     def capitalize(self) -> bytes: ...
     def center(self, __width: SupportsIndex, __fillchar: bytes = ...) -> bytes: ...
     def count(
@@ -705,7 +704,7 @@ class memoryview(Sized, Sequence[int]):
 
 @final
 class bool(int):
-    def __new__(cls: type[_T], __o: object = ...) -> _T: ...
+    def __new__(cls: type[Self], __o: object = ...) -> Self: ...
     @overload
     def __and__(self, __x: bool) -> bool: ...
     @overload
@@ -748,7 +747,7 @@ class slice:
     def indices(self, __len: SupportsIndex) -> tuple[int, int, int]: ...
 
 class tuple(Sequence[_T_co], Generic[_T_co]):
-    def __new__(cls: type[_T], __iterable: Iterable[_T_co] = ...) -> _T: ...
+    def __new__(cls: type[Self], __iterable: Iterable[_T_co] = ...) -> Self: ...
     def __len__(self) -> int: ...
     def __contains__(self, __x: object) -> bool: ...
     @overload
@@ -820,10 +819,10 @@ class list(MutableSequence[_T], Generic[_T]):
     def __setitem__(self, __s: slice, __o: Iterable[_T]) -> None: ...
     def __delitem__(self, __i: SupportsIndex | slice) -> None: ...
     def __add__(self, __x: list[_T]) -> list[_T]: ...
-    def __iadd__(self: _S, __x: Iterable[_T]) -> _S: ...
+    def __iadd__(self: Self, __x: Iterable[_T]) -> Self: ...
     def __mul__(self, __n: SupportsIndex) -> list[_T]: ...
     def __rmul__(self, __n: SupportsIndex) -> list[_T]: ...
-    def __imul__(self: _S, __n: SupportsIndex) -> _S: ...
+    def __imul__(self: Self, __n: SupportsIndex) -> Self: ...
     def __contains__(self, __o: object) -> bool: ...
     def __reversed__(self) -> Iterator[_T]: ...
     def __gt__(self, __x: list[_T]) -> bool: ...
@@ -847,7 +846,7 @@ class dict(MutableMapping[_KT, _VT], Generic[_KT, _VT]):
     # Cannot be Iterable[Sequence[_T]] or otherwise dict(["foo", "bar", "baz"]) is not an error
     @overload
     def __init__(self: dict[str, str], __iterable: Iterable[list[str]]) -> None: ...
-    def __new__(cls: type[_T1], *args: Any, **kwargs: Any) -> _T1: ...
+    def __new__(cls: type[Self], *args: Any, **kwargs: Any) -> Self: ...
     def copy(self) -> dict[_KT, _VT]: ...
     def keys(self) -> dict_keys[_KT, _VT]: ...
     def values(self) -> dict_values[_KT, _VT]: ...
@@ -1523,7 +1522,7 @@ class BaseException:
     if sys.version_info >= (3, 11):
         __note__: str | None
     def __init__(self, *args: object) -> None: ...
-    def with_traceback(self: _TBE, __tb: TracebackType | None) -> _TBE: ...
+    def with_traceback(self: Self, __tb: TracebackType | None) -> Self: ...
 
 class GeneratorExit(BaseException): ...
 class KeyboardInterrupt(BaseException): ...

stdlib/cgi.pyi

@@ -1,10 +1,8 @@
 import sys
-from _typeshed import SupportsGetItem, SupportsItemAccess
+from _typeshed import Self, SupportsGetItem, SupportsItemAccess
 from builtins import type as _type
 from collections.abc import Iterable, Iterator, Mapping
-from typing import IO, Any, Protocol, TypeVar
-
-_T = TypeVar("_T", bound=FieldStorage)
+from typing import IO, Any, Protocol
 
 def parse(
     fp: IO[Any] | None = ...,
@@ -93,7 +91,7 @@ class FieldStorage:
         max_num_fields: int | None = ...,
         separator: str = ...,
     ) -> None: ...
-    def __enter__(self: _T) -> _T: ...
+    def __enter__(self: Self) -> Self: ...
     def __exit__(self, *args: Any) -> None: ...
     def __iter__(self) -> Iterator[str]: ...
     def __getitem__(self, key: str) -> Any: ...

stdlib/codecs.pyi

@@ -2,7 +2,7 @@ import sys
 import types
 from _typeshed import Self
 from abc import abstractmethod
-from typing import IO, Any, BinaryIO, Callable, Generator, Iterable, Iterator, Protocol, TextIO, TypeVar, overload
+from typing import IO, Any, BinaryIO, Callable, Generator, Iterable, Iterator, Protocol, TextIO, overload
 from typing_extensions import Literal
 
 BOM32_BE: Literal[b"\xfe\xff"]
@@ -201,8 +201,6 @@ class StreamReader(Codec):
     def __iter__(self) -> Iterator[str]: ...
     def __getattr__(self, name: str, getattr: Callable[[str], Any] = ...) -> Any: ...
 
-_T = TypeVar("_T", bound=StreamReaderWriter)
-
 # Doesn't actually inherit from TextIO, but wraps a BinaryIO to provide text reading and writing
 # and delegates attributes to the underlying binary stream with __getattr__.
 class StreamReaderWriter(TextIO):
@@ -211,7 +209,7 @@ class StreamReaderWriter(TextIO):
     def readline(self, size: int | None = ...) -> str: ...
     def readlines(self, sizehint: int | None = ...) -> list[str]: ...
     def __next__(self) -> str: ...
-    def __iter__(self: _T) -> _T: ...
+    def __iter__(self: Self) -> Self: ...
     # This actually returns None, but that's incompatible with the supertype
     def write(self, data: str) -> int: ...
     def writelines(self, list: Iterable[str]) -> None: ...
@@ -233,8 +231,6 @@ class StreamReaderWriter(TextIO):
     def tell(self) -> int: ...
     def writable(self) -> bool: ...
 
-_SRT = TypeVar("_SRT", bound=StreamRecoder)
-
 class StreamRecoder(BinaryIO):
     def __init__(
         self,
@@ -249,7 +245,7 @@ class StreamRecoder(BinaryIO):
     def readline(self, size: int | None = ...) -> bytes: ...
     def readlines(self, sizehint: int | None = ...) -> list[bytes]: ...
     def __next__(self) -> bytes: ...
-    def __iter__(self: _SRT) -> _SRT: ...
+    def __iter__(self: Self) -> Self: ...
     def write(self, data: bytes) -> int: ...
     def writelines(self, list: Iterable[bytes]) -> int: ...  # type: ignore  # it's supposed to return None
     def reset(self) -> None: ...