Incorrect type if annotation comes before assignment

[Dreamsorcerer]

        method: Optional[Callable[[], Awaitable[StreamResponse]]]
        method = getattr(self, self.request.method.lower(), None)
        reveal_type(method)

aiohttp/web_urldispatcher.py:934: note: Revealed type is "Union[Any, None]"

vs.

        method: Optional[Callable[[], Awaitable[StreamResponse]]] = getattr(
            self, self.request.method.lower(), None)
        reveal_type(method)

aiohttp/web_urldispatcher.py:934: note: Revealed type is "Union[def () -> typing.Awaitable[aiohttp.web_response.StreamResponse], None]"

Expectation is that both versions should have the same type (and not be Any).

Tested with mypy 0.930.

Full code at: https://github.com/aio-libs/aiohttp/pull/6452/files#diff-9632858c8fdd45d817126b2735f763b9a2e24fb2800122eb2cb0c9a3b89c85c1

[erictraut]

Mypy doesn't currently apply narrowing to assignments if the assignment occurs on the same line as the type annotation.

This is a duplicate of #2008.