Use TypeAlias where possible for type aliases (#7630)

Author: AlexWaygood

stdlib/_codecs.pyi

@@ -1,13 +1,14 @@
 import codecs
 import sys
 from typing import Any, Callable
+from typing_extensions import TypeAlias
 
 # This type is not exposed; it is defined in unicodeobject.c
 class _EncodingMap:
     def size(self) -> int: ...
 
-_MapT = dict[int, int] | _EncodingMap
-_Handler = Callable[[Exception], tuple[str, int]]
+_MapT: TypeAlias = dict[int, int] | _EncodingMap
+_Handler: TypeAlias = Callable[[Exception], tuple[str, int]]
 
 def register(__search_function: Callable[[str], Any]) -> None: ...
 def register_error(__errors: str, __handler: _Handler) -> None: ...

stdlib/_csv.pyi

@@ -1,5 +1,5 @@
 from typing import Any, Iterable, Iterator, Protocol, Union
-from typing_extensions import Literal
+from typing_extensions import Literal, TypeAlias
 
 __version__: str
 
@@ -21,7 +21,7 @@ class Dialect:
     strict: int
     def __init__(self) -> None: ...
 
-_DialectLike = Union[str, Dialect, type[Dialect]]
+_DialectLike: TypeAlias = Union[str, Dialect, type[Dialect]]
 
 class _reader(Iterator[list[str]]):
     dialect: Dialect

stdlib/_curses.pyi

@@ -1,10 +1,10 @@
 import sys
 from _typeshed import SupportsRead
 from typing import IO, Any, NamedTuple, overload
-from typing_extensions import final
+from typing_extensions import TypeAlias, final
 
 if sys.platform != "win32":
-    _chtype = str | bytes | int
+    _chtype: TypeAlias = str | bytes | int
 
     # ACS codes are only initialized after initscr is called
     ACS_BBSS: int

stdlib/_dummy_threading.pyi

@@ -1,11 +1,12 @@
 import sys
 from types import FrameType, TracebackType
 from typing import Any, Callable, Iterable, Mapping, TypeVar
+from typing_extensions import TypeAlias
 
 # TODO recursive type
-_TF = Callable[[FrameType, str, Any], Callable[..., Any] | None]
+_TF: TypeAlias = Callable[[FrameType, str, Any], Callable[..., Any] | None]
 
-_PF = Callable[[FrameType, str, Any], None]
+_PF: TypeAlias = Callable[[FrameType, str, Any], None]
 _T = TypeVar("_T")
 
 if sys.version_info >= (3, 8):

stdlib/_operator.pyi

@@ -15,7 +15,7 @@ from typing import (
     TypeVar,
     overload,
 )
-from typing_extensions import ParamSpec, SupportsIndex, final
+from typing_extensions import ParamSpec, SupportsIndex, TypeAlias, final
 
 _R = TypeVar("_R")
 _T = TypeVar("_T")
@@ -40,7 +40,7 @@ class _SupportsDunderLE(Protocol):
 class _SupportsDunderGE(Protocol):
     def __ge__(self, __other: Any) -> Any: ...
 
-_SupportsComparison = _SupportsDunderLE | _SupportsDunderGE | _SupportsDunderGT | _SupportsDunderLT
+_SupportsComparison: TypeAlias = _SupportsDunderLE | _SupportsDunderGE | _SupportsDunderGT | _SupportsDunderLT
 
 class _SupportsInversion(Protocol[_T_co]):
     def __invert__(self) -> _T_co: ...

stdlib/_random.pyi

@@ -1,5 +1,7 @@
+from typing_extensions import TypeAlias
+
 # Actually Tuple[(int,) * 625]
-_State = tuple[int, ...]
+_State: TypeAlias = tuple[int, ...]
 
 class Random:
     def __init__(self, seed: object = ...) -> None: ...

stdlib/_socket.pyi

@@ -2,20 +2,21 @@ import sys
 from _typeshed import ReadableBuffer, WriteableBuffer
 from collections.abc import Iterable
 from typing import Any, SupportsInt, overload
+from typing_extensions import TypeAlias
 
 if sys.version_info >= (3, 8):
     from typing import SupportsIndex
 
-    _FD = SupportsIndex
+    _FD: TypeAlias = SupportsIndex
 else:
-    _FD = SupportsInt
+    _FD: TypeAlias = SupportsInt
 
-_CMSG = tuple[int, int, bytes]
-_CMSGArg = tuple[int, int, ReadableBuffer]
+_CMSG: TypeAlias = tuple[int, int, bytes]
+_CMSGArg: TypeAlias = tuple[int, int, ReadableBuffer]
 
 # Addresses can be either tuples of varying lengths (AF_INET, AF_INET6,
 # AF_NETLINK, AF_TIPC) or strings (AF_UNIX).
-_Address = tuple[Any, ...] | str
+_Address: TypeAlias = tuple[Any, ...] | str
 _RetAddress = Any
 # TODO Most methods allow bytes as address objects
 

stdlib/_threading_local.pyi

@@ -1,8 +1,9 @@
 from typing import Any
+from typing_extensions import TypeAlias
 from weakref import ReferenceType
 
 __all__ = ["local"]
-localdict = dict[Any, Any]
+localdict: TypeAlias = dict[Any, Any]
 
 class _localimpl:
     key: str

stdlib/_typeshed/__init__.pyi

@@ -99,7 +99,7 @@ StrPath: TypeAlias = str | PathLike[str]  # stable
 BytesPath: TypeAlias = bytes | PathLike[bytes]  # stable
 StrOrBytesPath: TypeAlias = str | bytes | PathLike[str] | PathLike[bytes]  # stable
 
-OpenTextModeUpdating = Literal[
+OpenTextModeUpdating: TypeAlias = Literal[
     "r+",
     "+r",
     "rt+",

stdlib/aifc.pyi

@@ -2,7 +2,7 @@ import sys
 from _typeshed import Self
 from types import TracebackType
 from typing import IO, Any, NamedTuple, overload
-from typing_extensions import Literal
+from typing_extensions import Literal, TypeAlias
 
 if sys.version_info >= (3, 9):
     __all__ = ["Error", "open"]
@@ -19,8 +19,8 @@ class _aifc_params(NamedTuple):
     comptype: bytes
     compname: bytes
 
-_File = str | IO[bytes]
-_Marker = tuple[int, int, bytes]
+_File: TypeAlias = str | IO[bytes]
+_Marker: TypeAlias = tuple[int, int, bytes]
 
 class Aifc_read:
     def __init__(self, f: _File) -> None: ...

stdlib/array.pyi

@@ -1,12 +1,12 @@
 import sys
 from _typeshed import Self
 from typing import Any, BinaryIO, Generic, Iterable, MutableSequence, TypeVar, overload
-from typing_extensions import Literal, SupportsIndex
+from typing_extensions import Literal, SupportsIndex, TypeAlias
 
-_IntTypeCode = Literal["b", "B", "h", "H", "i", "I", "l", "L", "q", "Q"]
-_FloatTypeCode = Literal["f", "d"]
-_UnicodeTypeCode = Literal["u"]
-_TypeCode = _IntTypeCode | _FloatTypeCode | _UnicodeTypeCode
+_IntTypeCode: TypeAlias = Literal["b", "B", "h", "H", "i", "I", "l", "L", "q", "Q"]
+_FloatTypeCode: TypeAlias = Literal["f", "d"]
+_UnicodeTypeCode: TypeAlias = Literal["u"]
+_TypeCode: TypeAlias = _IntTypeCode | _FloatTypeCode | _UnicodeTypeCode
 
 _T = TypeVar("_T", int, float, str)
 

stdlib/asyncio/base_events.pyi

@@ -9,7 +9,7 @@ from asyncio.transports import BaseTransport, ReadTransport, SubprocessTransport
 from collections.abc import Iterable
 from socket import AddressFamily, SocketKind, _Address, _RetAddress, socket
 from typing import IO, Any, Awaitable, Callable, Coroutine, Generator, Sequence, TypeVar, overload
-from typing_extensions import Literal
+from typing_extensions import Literal, TypeAlias
 
 if sys.version_info >= (3, 7):
     from contextvars import Context
@@ -23,10 +23,10 @@ else:
 
 _T = TypeVar("_T")
 _ProtocolT = TypeVar("_ProtocolT", bound=BaseProtocol)
-_Context = dict[str, Any]
-_ExceptionHandler = Callable[[AbstractEventLoop, _Context], Any]
-_ProtocolFactory = Callable[[], BaseProtocol]
-_SSLContext = bool | None | ssl.SSLContext
+_Context: TypeAlias = dict[str, Any]
+_ExceptionHandler: TypeAlias = Callable[[AbstractEventLoop, _Context], Any]
+_ProtocolFactory: TypeAlias = Callable[[], BaseProtocol]
+_SSLContext: TypeAlias = bool | None | ssl.SSLContext
 
 class Server(AbstractServer):
     if sys.version_info >= (3, 7):

stdlib/asyncio/base_subprocess.pyi

@@ -1,10 +1,11 @@
 import subprocess
 from collections import deque
 from typing import IO, Any, Callable, Sequence
+from typing_extensions import TypeAlias
 
 from . import events, futures, protocols, transports
 
-_File = int | IO[Any] | None
+_File: TypeAlias = int | IO[Any] | None
 
 class BaseSubprocessTransport(transports.SubprocessTransport):
 

stdlib/asyncio/events.pyi

@@ -4,7 +4,7 @@ from _typeshed import FileDescriptorLike, Self
 from abc import ABCMeta, abstractmethod
 from socket import AddressFamily, SocketKind, _Address, _RetAddress, socket
 from typing import IO, Any, Awaitable, Callable, Coroutine, Generator, Sequence, TypeVar, overload
-from typing_extensions import Literal
+from typing_extensions import Literal, TypeAlias
 
 from .base_events import Server
 from .futures import Future
@@ -75,10 +75,10 @@ else:
 
 _T = TypeVar("_T")
 _ProtocolT = TypeVar("_ProtocolT", bound=BaseProtocol)
-_Context = dict[str, Any]
-_ExceptionHandler = Callable[[AbstractEventLoop, _Context], Any]
-_ProtocolFactory = Callable[[], BaseProtocol]
-_SSLContext = bool | None | ssl.SSLContext
+_Context: TypeAlias = dict[str, Any]
+_ExceptionHandler: TypeAlias = Callable[[AbstractEventLoop, _Context], Any]
+_ProtocolFactory: TypeAlias = Callable[[], BaseProtocol]
+_SSLContext: TypeAlias = bool | None | ssl.SSLContext
 
 class Handle:
     _cancelled: bool

stdlib/asyncio/format_helpers.pyi

@@ -2,11 +2,12 @@ import functools
 import traceback
 from types import FrameType, FunctionType
 from typing import Any, Iterable, overload
+from typing_extensions import TypeAlias
 
 class _HasWrapper:
     __wrapper__: _HasWrapper | FunctionType
 
-_FuncType = FunctionType | _HasWrapper | functools.partial[Any] | functools.partialmethod[Any]
+_FuncType: TypeAlias = FunctionType | _HasWrapper | functools.partial[Any] | functools.partialmethod[Any]
 
 @overload
 def _get_function_source(func: _FuncType) -> tuple[str, int]: ...

stdlib/asyncio/streams.pyi

@@ -1,6 +1,7 @@
 import sys
 from _typeshed import Self, StrPath
 from typing import Any, AsyncIterator, Awaitable, Callable, Iterable, Sequence
+from typing_extensions import TypeAlias
 
 from . import events, protocols, transports
 from .base_events import Server
@@ -64,7 +65,7 @@ else:
             "start_unix_server",
         ]
 
-_ClientConnectedCallback = Callable[[StreamReader, StreamWriter], Awaitable[None] | None]
+_ClientConnectedCallback: TypeAlias = Callable[[StreamReader, StreamWriter], Awaitable[None] | None]
 
 if sys.version_info < (3, 8):
     class IncompleteReadError(EOFError):

stdlib/asyncio/subprocess.pyi

@@ -3,17 +3,17 @@ import sys
 from _typeshed import StrOrBytesPath
 from asyncio import events, protocols, streams, transports
 from typing import IO, Any, Callable
-from typing_extensions import Literal
+from typing_extensions import Literal, TypeAlias
 
 if sys.version_info >= (3, 7):
     __all__ = ("create_subprocess_exec", "create_subprocess_shell")
 else:
     __all__ = ["create_subprocess_exec", "create_subprocess_shell"]
 
 if sys.version_info >= (3, 8):
-    _ExecArg = StrOrBytesPath
+    _ExecArg: TypeAlias = StrOrBytesPath
 else:
-    _ExecArg = str | bytes
+    _ExecArg: TypeAlias = str | bytes
 
 PIPE: int
 STDOUT: int

stdlib/asyncio/tasks.pyi

@@ -3,7 +3,7 @@ import sys
 from collections.abc import Awaitable, Generator, Iterable, Iterator
 from types import FrameType
 from typing import Any, Coroutine, Generic, TextIO, TypeVar, overload
-from typing_extensions import Literal
+from typing_extensions import Literal, TypeAlias
 
 from .events import AbstractEventLoop
 from .futures import Future
@@ -56,8 +56,8 @@ _T3 = TypeVar("_T3")
 _T4 = TypeVar("_T4")
 _T5 = TypeVar("_T5")
 _FT = TypeVar("_FT", bound=Future[Any])
-_FutureT = Future[_T] | Generator[Any, None, _T] | Awaitable[_T]
-_TaskYieldType = Future[object] | None
+_FutureT: TypeAlias = Future[_T] | Generator[Any, None, _T] | Awaitable[_T]
+_TaskYieldType: TypeAlias = Future[object] | None
 
 FIRST_COMPLETED = concurrent.futures.FIRST_COMPLETED
 FIRST_EXCEPTION = concurrent.futures.FIRST_EXCEPTION

stdlib/asyncio/trsock.pyi

@@ -3,12 +3,13 @@ import sys
 from builtins import type as Type  # alias to avoid name clashes with property named "type"
 from types import TracebackType
 from typing import Any, BinaryIO, Iterable, NoReturn, overload
+from typing_extensions import TypeAlias
 
 # These are based in socket, maybe move them out into _typeshed.pyi or such
-_Address = tuple[Any, ...] | str
-_RetAddress = Any
-_WriteBuffer = bytearray | memoryview
-_CMSG = tuple[int, int, bytes]
+_Address: TypeAlias = tuple[Any, ...] | str
+_RetAddress: TypeAlias = Any
+_WriteBuffer: TypeAlias = bytearray | memoryview
+_CMSG: TypeAlias = tuple[int, int, bytes]
 
 class TransportSocket:
     def __init__(self, sock: socket.socket) -> None: ...

stdlib/asyncore.pyi

@@ -2,10 +2,11 @@ import sys
 from _typeshed import FileDescriptorLike
 from socket import socket
 from typing import Any, overload
+from typing_extensions import TypeAlias
 
 # cyclic dependence with asynchat
-_maptype = dict[int, Any]
-_socket = socket
+_maptype: TypeAlias = dict[int, Any]
+_socket: TypeAlias = socket
 
 socket_map: _maptype  # undocumented
 

stdlib/audioop.pyi

@@ -1,5 +1,7 @@
-AdpcmState = tuple[int, int]
-RatecvState = tuple[int, tuple[tuple[int, int], ...]]
+from typing_extensions import TypeAlias
+
+AdpcmState: TypeAlias = tuple[int, int]
+RatecvState: TypeAlias = tuple[int, tuple[tuple[int, int], ...]]
 
 class error(Exception): ...
 

stdlib/bdb.pyi

@@ -1,13 +1,13 @@
 from types import CodeType, FrameType, TracebackType
 from typing import IO, Any, Callable, Iterable, Mapping, SupportsInt, TypeVar
-from typing_extensions import Literal, ParamSpec
+from typing_extensions import Literal, ParamSpec, TypeAlias
 
 __all__ = ["BdbQuit", "Bdb", "Breakpoint"]
 
 _T = TypeVar("_T")
 _P = ParamSpec("_P")
-_TraceDispatch = Callable[[FrameType, str, Any], Any]  # TODO: Recursive type
-_ExcInfo = tuple[type[BaseException], BaseException, FrameType]
+_TraceDispatch: TypeAlias = Callable[[FrameType, str, Any], Any]  # TODO: Recursive type
+_ExcInfo: TypeAlias = tuple[type[BaseException], BaseException, FrameType]
 
 GENERATOR_AND_COROUTINE_FLAGS: Literal[672]
 

stdlib/binhex.pyi

@@ -1,5 +1,5 @@
 from typing import IO, Any
-from typing_extensions import Literal
+from typing_extensions import Literal, TypeAlias
 
 __all__ = ["binhex", "hexbin", "Error"]
 
@@ -15,8 +15,8 @@ class FInfo:
     Creator: str
     Flags: int
 
-_FileInfoTuple = tuple[str, FInfo, int, int]
-_FileHandleUnion = str | IO[bytes]
+_FileInfoTuple: TypeAlias = tuple[str, FInfo, int, int]
+_FileHandleUnion: TypeAlias = str | IO[bytes]
 
 def getfileinfo(name: str) -> _FileInfoTuple: ...