Overloads in generic classes are extremely slow when using generic self

Bug Report

Performance of mypy degrades drastically with the number of type variable constraints when checking overloaded method of generic class with overloaded self.

To Reproduce

from typing import TypeVar, Generic, TypeAlias, overload, Any


T1 = TypeVar('T1', int, str, bool)
T2 = TypeVar('T2', int, str, bool)
T3 = TypeVar('T3', int, str, bool)
T4 = TypeVar('T4', int, str, bool)
T5 = TypeVar('T5', int, str, bool)
T6 = TypeVar('T6', int, str, bool)
T7 = TypeVar('T7', int, str, bool)


class A(Generic[T1, T2, T3, T4, T5, T6, T7]):
    @overload
    def foo(self: A[int, T2, T3, T4, T5, T6, T7]) -> int:
        ...
    
    @overload
    def foo(self: A[str, T2, T3, T4, T5, T6, T7]) -> str:
        ...
        
    def foo(self) -> int | str:
        raise NotImplementedError

https://mypy-play.net/?mypy=latest&python=3.12&gist=fd939322936206cbb9b1f45a71fbd9b7

Expected Behavior

Code typechecks in realistic time. For reference pyrights checks such code without significant performance issues

Actual Behavior

mypy-play.net times out. In my experience it takes at least more than 10 minutes to check such code. Interestingly, when converting foo method to an independent function taking A as a parameter typechecking time drops significantly.

Your Environment

python3.11 and python3.12, both mypy 1.12.1 and 1.13

Comienza con la reproducción de Python proporcionada y el enlace de mypy-play, luego compara su tiempo de comprobación con la variante de función independiente descrita en el informe. Mide cómo cambia el tiempo de ejecución a medida que aumenta el número de variables de tipo restringidas y utiliza el comportamiento esperado —la comprobación de tipos en un tiempo realista— como criterio de finalización.