Bug: mypy is confusing the type of the getter with that of the setter

[AbdulRahmanAlHamali]

Hello, starting v0.720, the following code:

from typing import Union


class Test:
    def __init__(self, something: Union[int, str]):
        self.something = something

    @property
    def something(self) -> str:
        return self._something

    @something.setter
    def something(self, val: Union[int, str]) -> None:
        if isinstance(val, int):
            self._something = str(val)
        else:
            self._something = val

fails with the following error:

error: Incompatible types in assignment (expression has type "Union[int, str]", variable has type "str")

It seems that mypy is confusing the type of the getter with the type of the setter. Any idea what might be causing this?

Thanks!

[ilevkivskyi]

Properties with different getter and setter types were never supported see #3004. It was not caught before because there was a bug that all properties defined after they use in __init__() were silently turned into Any.