"Incompatible with definition in base class" with generics

[eltoder]

To Reproduce

https://mypy-play.net/?mypy=latest&python=3.11&gist=fd4559c9942bc1991500fb402ca989f3

from typing import Generic, TypeVar

T = TypeVar("T")
U = TypeVar("U")

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

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

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

Expected Behavior

I expect this to type check, since x in both bases are using exactly the same type after substitution of generic arguments. I'm guessing the compatibility check is performed before the substitution, but it should be after.

Actual Behavior

main.py:12: error: Definition of "x" in base class "A" is incompatible with definition in base class "B"  [misc]

Your Environment

• Mypy version used: 1.5.1
• Python version used: 3.11

[erictraut]

This appears to be a duplicate of #2875.

[eltoder]

@erictraut thanks! Indeed, very similar to #2875 (comment), except in my case both classes are generic. Probably the same issue.