Closed
Description
Consider this fragment:
from typing import Union, Dict
x = {} # type: Dict[str, Union[int, str]]
n = ''
if isinstance(x[n], int):
reveal_type(x[n]) # E: Revealed type is 'Union[builtins.int, builtins.str]'
Perhaps mypy should infer type int for x[n] (i.e. put x[n] into the conditional type binder).
The example can be refactored to type check pretty easily:
...
t = x[n]
if isinstance(t, int):
...
A slightly more interesting example that is a bit harder to get to type check:
...
if n in x and isinstance(x[n], int):
...
This was originally reported by @davire on gitter.