Avoid TypeAlias at runtime

src/attr/__init__.py

@@ -9,7 +9,6 @@
 
 from . import converters, exceptions, filters, setters, validators
 from ._cmp import cmp_using
-from ._compat import TypeAlias
 from ._config import get_run_validators, set_run_validators
 from ._funcs import asdict, assoc, astuple, evolve, has, resolve_types
 from ._make import (
@@ -38,7 +37,7 @@ class AttrsInstance(Protocol):
     pass
 
 
-NothingType: TypeAlias = Literal[_Nothing.NOTHING]
+NothingType = Literal[_Nothing.NOTHING]
 
 __all__ = [
     "Attribute",

src/attr/__init__.pyi

@@ -9,7 +9,6 @@ from typing import (
     Mapping,
     Protocol,
     Sequence,
-    TypeAlias,
     TypeVar,
     overload,
 )
@@ -39,9 +38,9 @@ from attrs import (
 )
 
 if sys.version_info >= (3, 10):
-    from typing import TypeGuard
+    from typing import TypeGuard, TypeAlias
 else:
-    from typing_extensions import TypeGuard
+    from typing_extensions import TypeGuard, TypeAlias
 
 if sys.version_info >= (3, 11):
     from typing import dataclass_transform

src/attr/_compat.py

@@ -17,10 +17,6 @@
 PY_3_13_PLUS = sys.version_info[:2] >= (3, 13)
 PY_3_14_PLUS = sys.version_info[:2] >= (3, 14)
 
-try:
-    from typing import TypeAlias
-except ImportError:
-    from typing_extensions import TypeAlias  # noqa: F401
 
 if PY_3_14_PLUS:  # pragma: no cover
     import annotationlib