Subclassing a contextmanager fails

[euresti]

from contextlib import contextmanager
from typing import Iterator

class Foo(object):
    @contextmanager
    def bar(self):
        # type: () -> Iterator[int]
        yield 4

class Bar(Foo):
    @contextmanager
    def bar(self):
        # type: () -> Iterator[int]
        yield 3

reveal_type(Foo.bar)
reveal_type(Bar.bar)

Fails thus:

t5.py: note: In class "Bar":
t5.py:12: error: Signature of "bar" incompatible with supertype "Foo"
t5.py: note: At top level:
t5.py:17: error: Revealed type is 'def (*Any, **Any) -> contextlib.ContextManager[builtins.int*]'
t5.py:18: error: Revealed type is 'def (*Any, **Any) -> contextlib.ContextManager[builtins.int*]'

[JukkaL]

You can use # type: ignore as a workaround.

[thomasballinger]

Maybe the same bug, if so this is more general than contextmanager.

def arbitrary_decorator(f):
    return f

class Foo(object):
    @arbitrary_decorator
    def bar(self):
        # type: () -> int
        return 4

class Bar(Foo):
    @arbitrary_decorator
    def bar(self):
        # type: () -> int
        return 3

reveal_type(Foo.bar)
reveal_type(Bar.bar)

gives

tmp.py:12: error: Signature of "bar" incompatible with supertype "Foo"
tmp.py:16: error: Revealed type is 'Any'
tmp.py:17: error: Revealed type is 'Any'

[FuegoFro]

Is this a duplicate of #1441? Also is this possibly related to the forward referencing issue listed in #2907 (comment)?

[JukkaL]

Yes, this looks like a duplicate of #1441. This likely isn't related to forward references.