Use explicit type aliases in _typeshed (#7534)

requirements-tests.txt

@@ -1,5 +1,5 @@
 mypy==0.942
-pytype==2022.3.21; platform_system != "Windows" and python_version < "3.10"
+pytype==2022.03.29; platform_system != "Windows" and python_version < "3.10"
 # must match .pre-commit-config.yaml
 black==22.1.0
 flake8==4.0.1

stdlib/_typeshed/__init__.pyi

@@ -58,7 +58,7 @@ class SupportsDunderGE(Protocol):
 
 class SupportsAllComparisons(SupportsDunderLT, SupportsDunderGT, SupportsDunderLE, SupportsDunderGE, Protocol): ...
 
-SupportsRichComparison = SupportsDunderLT | SupportsDunderGT
+SupportsRichComparison: TypeAlias = SupportsDunderLT | SupportsDunderGT
 SupportsRichComparisonT = TypeVar("SupportsRichComparisonT", bound=SupportsRichComparison)  # noqa: Y001
 
 class SupportsDivMod(Protocol[_T_contra, _T_co]):
@@ -95,9 +95,9 @@ class SupportsItemAccess(SupportsGetItem[_KT_contra, _VT], Protocol[_KT_contra,
     def __delitem__(self, __v: _KT_contra) -> None: ...
 
 # These aliases are simple strings in Python 2.
-StrPath = str | PathLike[str]  # stable
-BytesPath = bytes | PathLike[bytes]  # stable
-StrOrBytesPath = str | bytes | PathLike[str] | PathLike[bytes]  # stable
+StrPath: TypeAlias = str | PathLike[str]  # stable
+BytesPath: TypeAlias = bytes | PathLike[bytes]  # stable
+StrOrBytesPath: TypeAlias = str | bytes | PathLike[str] | PathLike[bytes]  # stable
 
 OpenTextModeUpdating = Literal[
     "r+",
@@ -133,10 +133,10 @@ OpenTextModeUpdating = Literal[
     "t+x",
     "+tx",
 ]
-OpenTextModeWriting = Literal["w", "wt", "tw", "a", "at", "ta", "x", "xt", "tx"]
-OpenTextModeReading = Literal["r", "rt", "tr", "U", "rU", "Ur", "rtU", "rUt", "Urt", "trU", "tUr", "Utr"]
-OpenTextMode = OpenTextModeUpdating | OpenTextModeWriting | OpenTextModeReading
-OpenBinaryModeUpdating = Literal[
+OpenTextModeWriting: TypeAlias = Literal["w", "wt", "tw", "a", "at", "ta", "x", "xt", "tx"]
+OpenTextModeReading: TypeAlias = Literal["r", "rt", "tr", "U", "rU", "Ur", "rtU", "rUt", "Urt", "trU", "tUr", "Utr"]
+OpenTextMode: TypeAlias = OpenTextModeUpdating | OpenTextModeWriting | OpenTextModeReading
+OpenBinaryModeUpdating: TypeAlias = Literal[
     "rb+",
     "r+b",
     "+rb",
@@ -162,16 +162,16 @@ OpenBinaryModeUpdating = Literal[
     "b+x",
     "+bx",
 ]
-OpenBinaryModeWriting = Literal["wb", "bw", "ab", "ba", "xb", "bx"]
-OpenBinaryModeReading = Literal["rb", "br", "rbU", "rUb", "Urb", "brU", "bUr", "Ubr"]
-OpenBinaryMode = OpenBinaryModeUpdating | OpenBinaryModeReading | OpenBinaryModeWriting
+OpenBinaryModeWriting: TypeAlias = Literal["wb", "bw", "ab", "ba", "xb", "bx"]
+OpenBinaryModeReading: TypeAlias = Literal["rb", "br", "rbU", "rUb", "Urb", "brU", "bUr", "Ubr"]
+OpenBinaryMode: TypeAlias = OpenBinaryModeUpdating | OpenBinaryModeReading | OpenBinaryModeWriting
 
 # stable
 class HasFileno(Protocol):
     def fileno(self) -> int: ...
 
-FileDescriptor = int  # stable
-FileDescriptorLike = int | HasFileno  # stable
+FileDescriptor: TypeAlias = int  # stable
+FileDescriptorLike: TypeAlias = int | HasFileno  # stable
 
 # stable
 class SupportsRead(Protocol[_T_co]):
@@ -189,13 +189,13 @@ class SupportsNoArgReadline(Protocol[_T_co]):
 class SupportsWrite(Protocol[_T_contra]):
     def write(self, __s: _T_contra) -> object: ...
 
-ReadOnlyBuffer = bytes  # stable
+ReadOnlyBuffer: TypeAlias = bytes  # stable
 # Anything that implements the read-write buffer interface.
 # The buffer interface is defined purely on the C level, so we cannot define a normal Protocol
 # for it. Instead we have to list the most common stdlib buffer classes in a Union.
-WriteableBuffer = bytearray | memoryview | array.array[Any] | mmap.mmap | ctypes._CData  # stable
+WriteableBuffer: TypeAlias = bytearray | memoryview | array.array[Any] | mmap.mmap | ctypes._CData  # stable
 # Same as _WriteableBuffer, but also includes read-only buffer types (like bytes).
-ReadableBuffer = ReadOnlyBuffer | WriteableBuffer  # stable
+ReadableBuffer: TypeAlias = ReadOnlyBuffer | WriteableBuffer  # stable
 
 # stable
 if sys.version_info >= (3, 10):

stdlib/_typeshed/dbapi.pyi

@@ -3,11 +3,12 @@
 
 from collections.abc import Mapping, Sequence
 from typing import Any, Protocol
+from typing_extensions import TypeAlias
 
-DBAPITypeCode = Any | None
+DBAPITypeCode: TypeAlias = Any | None
 # Strictly speaking, this should be a Sequence, but the type system does
 # not support fixed-length sequences.
-DBAPIColumnDescription = tuple[str, DBAPITypeCode, int | None, int | None, int | None, int | None, bool | None]
+DBAPIColumnDescription: TypeAlias = tuple[str, DBAPITypeCode, int | None, int | None, int | None, int | None, bool | None]
 
 class DBAPIConnection(Protocol):
     def close(self) -> object: ...

stdlib/_typeshed/wsgi.pyi

@@ -4,6 +4,7 @@
 
 from sys import _OptExcInfo
 from typing import Any, Callable, Iterable, Protocol
+from typing_extensions import TypeAlias
 
 # stable
 class StartResponse(Protocol):
@@ -11,8 +12,8 @@ class StartResponse(Protocol):
         self, status: str, headers: list[tuple[str, str]], exc_info: _OptExcInfo | None = ...
     ) -> Callable[[bytes], Any]: ...
 
-WSGIEnvironment = dict[str, Any]  # stable
-WSGIApplication = Callable[[WSGIEnvironment, StartResponse], Iterable[bytes]]  # stable
+WSGIEnvironment: TypeAlias = dict[str, Any]  # stable
+WSGIApplication: TypeAlias = Callable[[WSGIEnvironment, StartResponse], Iterable[bytes]]  # stable
 
 # WSGI input streams per PEP 3333, stable
 class InputStream(Protocol):