typing_extension.Self infers the wrong type from __new__

[Avasam]

Note: if you are reporting a wrong signature of a function or a class in the standard library, then the typeshed tracker is better suited for this report: https://github.com/python/typeshed/issues.

Describe the bug
When using __new__ directly (example below), the return type is the class itself instead of inferring from the first classmethod param (cls)

To Reproduce

import enum
from typing_extensions import Self, reveal_type


class ActionLevel(enum.IntEnum):
    def __new__(cls, value: int, doc: str) -> Self:
        member = int.__new__(cls, value)
        reveal_type(member)
        member._value_ = value
        member.__doc__ = doc
        return member

Expected behavior
member should be ActionLevel not int

Screenshots or Code

VS Code extension or command-line
Both.
npx pyright@1.1.294 .\scripts\stubsabot.py

Additional context
This was first found here: python/typeshed#9694 (comment)

[erictraut]

I'm not able to repro the problem you're seeing. Here's the behavior I see:

Can you confirm that when you paste the above code into a new editor window in a new project with default pyright settings that you get an error?

Perhaps you have an old version of typing_extensions or typing_extensions-stubs installed in your environment?

[Avasam]

typing_extensions is 4.5.0
I narrowed down what in the configs causes it: setting "typeshedPath". In this case, my minimal pyrightconfig.json is as such:

{
    "$schema": "https://raw.githubusercontent.com/microsoft/pyright/main/packages/vscode-pyright/schemas/pyrightconfig.schema.json",
    "typeshedPath": ".",
}

I can confirm I have no typing_extensions-stubs in my env:

Note this happens with typing too:
npx pyright@1.1.294 .\scripts\stubsabot.py --pythonversion=3.11

pyright 1.1.294
E:\Users\Avasam\Documents\Git\typeshed\scripts\stubsabot.py
  E:\Users\Avasam\Documents\Git\typeshed\scripts\stubsabot.py:8:21 - information: Type of "member" is "int"
  E:\Users\Avasam\Documents\Git\typeshed\scripts\stubsabot.py:9:16 - error: Cannot assign member "_value_" for type "int"
    Member "_value_" is unknown (reportGeneralTypeIssues)
  E:\Users\Avasam\Documents\Git\typeshed\scripts\stubsabot.py:11:16 - error: Expression of type "int" cannot be assigned to return type "Self@ActionLevel"
    "int" is incompatible with "ActionLevel" (reportGeneralTypeIssues)
2 errors, 0 warnings, 1 information

Is this something that can be fixed on typeshed's side? Or is it due to some special casing done with "typeshedPath" ?

[erictraut]

Ah, you're using a version of typeshed that is newer than what is bundled with pyright 1.1.294. That's an important detail! I'm able to repro the problem now, so I'll investigate further.

[erictraut]

Thanks for the bug report. This will be addressed in the next release.

[erictraut]

This is addressed in pyright 1.1.295, which I just published. It will also be included in a future release of pylance.