class-with-mixed-type-vars (RUF053)
Fix is sometimes available.
This rule is unstable and in preview. The --preview flag is required for use.
What it does
Checks for classes that have PEP 695
while also inheriting from typing.Generic or typing_extensions.Generic.
Why is this bad?
Such classes cause errors at runtime:
from typing import Generic, TypeVar
U = TypeVar("U")
# TypeError: Cannot inherit from Generic[...] multiple times.
class C[T](Generic[U]): ...
Example
from typing import Generic, ParamSpec, TypeVar, TypeVarTuple
U = TypeVar("U")
P = ParamSpec("P")
Ts = TypeVarTuple("Ts")
class C[T](Generic[U, P, *Ts]): ...
Use instead:
Fix safety
As the fix changes runtime behaviour, it is always marked as unsafe. Additionally, comments within the fix range will not be preserved.