Mypy treats types with __getitem__ as not iterables

[sobolevn]

Sample:

class Some:
    def __getitem__(self, i: int) -> str:
        if i >= 2:
            raise IndexError()
        return chr(97 + i)

s = Some()
for x in s:  # error here
    print(x)

Output:

» mypy out/ex.py --strict-optional --warn-unreachable --show-traceback
out/ex.py:10: error: "Some" has no attribute "__iter__" (not iterable)

But, in runtime it works just fine:

» python out/ex.py
a
b

Docs: https://pyneng.readthedocs.io/en/latest/book/23_oop_special_methods/iterable_iterator.html#iteration-protocol

I will try to send a PR soon!

[JelleZijlstra]

I'm pretty sure there's already a bug for this. Thanks for working on it!

[sobolevn]

Yes: #2220 Found it!

[hauntsaninja]

@sobolevn want to review #10386 ?

[sobolevn]

@hauntsaninja done!