enumerate(self) type unknown

[fried]

Environment data

• Language Server version: 2020.9.6
• OS and version: macOS 10.15.6
• Python version (& distribution if applicable, e.g. Anaconda): cpython3.8.5

Expected behaviour

for i, value in enumerate(self): # (variable) value: bool
...

Actual behaviour

(variable) value: Unknown
Type of "value" is unknownPylance (reportUnknownVariableType)

But the following works just fine

for i, value in enumerate(BitBlob()):   # (variable) value: bool
     pass 

Code Snippet / Additional information

class BitBlob:
         def bad_types(self) -> None:
                for i, value in enumerate(self):
                      pass

         def good_types(self) -> None:
               for i, value in enumerate(BitBlob()):
                      pass

         def __iter__(self) -> Iterator[bool]:  ...

[fried]

I have a workaround, this works even though it knew that self was a BitBlob before

def bad_types(self: BitBlob) -> None:
    for i, value in enumerate(self):
         pass

[jakebailey]

I can reproduce this.

@erictraut

[erictraut]

Thanks for reporting the problem. This will be fixed in the next release.

[jakebailey]

This issue has been fixed in version 2020.9.7, which we've just released. You can find the changelog here: https://github.com/microsoft/pylance-release/blob/master/CHANGELOG.md#202097-30-september-2020