Failure when overriding an protocol attribute with a property in protocol subclass

[cmeyer]

Bug Report

Unexpected typing failure when subclassing protocol.

To Reproduce

mypy --strict f.py

f.py:

import typing

class B(typing.Protocol):
    field1: float

class D(B):
    @property
    def field1(self) -> float: return 0

    @field1.setter
    def field1(self, v: float) -> None: pass

class E:
    @property
    def field1(self) -> float: return 0

    @field1.setter
    def field1(self, v: float) -> None: pass

Expected Behavior

Both classes, D and E, should pass type checking.

Actual Behavior

The D class fails type checking:

f.py:7: error: Signature of "field1" incompatible with supertype "B"
f.py:8: error: Signature of "field1" incompatible with supertype "B"
Found 2 errors in 1 file (checked 1 source file)

Your Environment

Multiple environments.

% mypy --version
mypy 0.982 (compiled: yes)

[tmke8]

This was fixed by #13475 which hasn't been released yet, but you can try it out on mypy master.

[hauntsaninja]

Thanks for the issue report and thanks for linking the fix!