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"Callable | Callable" not callable [misc] #17631
Description
The following code:
from collections.abc import Callable, Sequence
from functools import partial, reduce
from typing import cast, Any
CA = Callable[[Any], Any]
CB = Callable[[Callable[..., Any], Any], Any]
def f(s: Sequence[CA | CB]) -> CA:
return cast(CA, reduce(lambda a, b: partial(b, a), s))produces the following output:
test.py: note: In function "f":
test.py:9:41: error: "Callable[[Any], Any] | Callable[[Callable[..., Any], Any], Any]" not callable [misc]
return cast(CA, reduce(lambda a, b: partial(b, a), s))
^This looks like a false positive to me.
$ mypy --version
mypy 1.11.1 (compiled: yes)
$ python --version
Python 3.12.3
$ lsb_release -d
No LSB modules are available.
Description: Ubuntu 24.04 LTSReacted by Rahul Iyer and Bartosz Sławecki
Activity
hauntsaninja commentedon Aug 9, 2024
This is the same as many other issues, where mypy computes join between callables to
builtins.function. In this case join of[def (Any) -> Anyanddef (def (*Any, **Any) -> Any, Any) -> Any]. Happens to shows up in 1.11 because we now type check functools.partial more closely, but underlying issue is old. Seems tricky to turn the callsite inextract_callable_typeto return a unionjohnslavik commentedon Aug 9, 2024
I've taken on the challenge of fixing this. It's my first time working with mypy, so bear with me or let me know if someone else fixes it.
jolaf commentedon Aug 9, 2024
Thanks!!
hauntsaninja commentedon Jan 1, 2025
This was fixed in #17903