Multiple inheritance with Generic leads to [misc] error

[Lancetnik]

Bug Report

If we creates multiple generic parents with the same generic attribute, mypy raises an error about incompatible definition

To Reproduce

from typing import Generic, TypeVar

T = TypeVar("T")

class A(Generic[T]):
    x: T

class B(Generic[T]):
    x: T

class C(A[str], B[str]):
    pass

Raises error: Definition of "x" in base class "A" is incompatible with definition in base class "B" [misc]

Expected Behavior

The example should has no error, like in the final types case

class A:
    x: str

class B:
    x: str

class C(A, B):
    pass

Actual Behavior

Raises an error

Your Environment

mypy==1.14.0

[Lancetnik]

I would like to solve the problem if smbd can lead me to the right direction

[Lancetnik]

Well, the problem is in is_equivalent function result
It validates two TypeVarTypes, that contains TypeVarId differs by namespace. They has A and B classes values, but seems like the correct one is C or str

[Lancetnik]

Seems like it is related to #18189 and #14774 as well