`ClassVar` cannot contain `Self` type in generic classes

This rule seems correct when Self appears in a covariant position, like

class MyGeneric[T]:
    # ill-defined, what's the type of MySequence.example?
    example: ClassVar[Self]  # error: ClassVar cannot contain Self type in generic classes

However, if Self appears in a contravariant position, I do not see why this should be an error.

class MyGeneric[T]:
    pre_method_hooks: ClassVar[list[ Callable[[Self], None] ]] = []

Full example: https://mypy-play.net/?mypy=master&python=3.12&gist=951d5b3a168378cd33d9fc4aebd4572e

from typing import Callable, ClassVar, Self, Any
from abc import abstractmethod

class Transform[X, Y]:
    pre_transform_hooks: ClassVar[list[Callable[[Self], None]]] = []  # ❌️

    def __init_subclass__(cls) -> None:
        super().__init_subclass__()
        original_transform = cls.transform

        def wrapped_transform(self: Self, x: X, /, *args: Any, **kwargs: Any) -> Y:
            for hook in cls.pre_transform_hooks:
                hook(self)
            return original_transform(self, x, *args, **kwargs)
        cls.transform = wrapped_transform  # type: ignore[method-assign]

    @abstractmethod
    def transform(self, x: X, /) -> Y: ...

class Demo(Transform[int, int]):
    def transform(self, x: int, /) -> int: return 0

    def hello_world(self) -> None:
        print(f"Hello, world! from {self}")

    pre_transform_hooks: ClassVar[list[Callable]] = [hello_world]

Demo().transform(0)  # prints "Hello, world! from <__main__.Demo object at ...>"

main.py:5: error: ClassVar cannot contain Self type in generic classes  [misc]
Found 1 error in 1 file (checked 1 source file)

Reproduziere die Diagnose anhand des verlinkten mypy-play-Beispiels oder des gezeigten main.py-Snippets und verfolge anschließend die ClassVar- und Self-Validierung, die das generische Klassenmitglied ablehnt. Vergleiche die kovarianten und kontravarianten Fälle und prüfe vorhandene Tests für diese Regel. Erledigt ist die Aufgabe, wenn der beabsichtigte kontravariante Fall konsistent behandelt wird, während der ungültige kovariante Fall weiterhin diagnostiziert wird.