overloaded __new__ ignored when introducing __init__ #17251

from __future__ import annotations

from typing import (
    Any,
    Generic,
    TypeVar,
    overload,
)

BE = TypeVar("BE", bound=BaseException)
E = TypeVar("E", bound=Exception)


class MyBaseClass(Generic[BE]):
    @overload
    def __new__(cls, arg: type[E]) -> MyClass[E]:
        ...
    @overload
    def __new__(cls, arg: type[BE]) -> MyBaseClass[BE]:
        ...

    def __new__(cls, arg: Any) -> Any:
        if issubclass(arg, Exception):
            return MyClass(arg)
        return MyBaseClass(arg)

    def __init__(self, arg: type[BE]):  # pyright: ignore[reportInconsistentConstructor]
        self.arg = arg

class MyClass(MyBaseClass[E]):
    def __init__(self, arg: type[E]):  # pyright: ignore[reportInconsistentConstructor]
        self.arg = arg


reveal_type(MyBaseClass(ValueError))
reveal_type(MyBaseClass(KeyboardInterrupt))