Show better hints for namedtuple __init__()

[ARF1]

Environment data

• Language Server version: 2020.11.1
• OS and version: Windows 10
• Python version (& distribution if applicable, e.g. Anaconda): Miniconda Python 3.9

Actual behaviour

Pylance is missing argument information:

Note that pylance seems to already have the required information as attested by this error message:

Expected behaviour

Behaviour analogous to:

[erictraut]

Thanks for the suggestion.

The __new__ and __init__ methods for namedtuple and NamedTuple are synthesized by pyright. The __new__ method contains all of the fields, but __init__ contains only generic *args and **kwargs. The signature help is using the __init__ method, so it's showing the less useful of the two in this case.

There are a couple of potential ways we could fix this. I'll need to think more about which one is better.

[erictraut]

This will be fixed in the next release.

[ARF1]

Great thank you.

[jakebailey]

This issue has been fixed in version 2020.12.0, which we've just released. You can find the changelog here: https://github.com/microsoft/pylance-release/blob/master/CHANGELOG.md#2020120-2-december-2020