Value of type variable "Self" of "__new__" of "tuple" cannot be <some subclass of typing.Tuple>

[robsdedude]

Bug Report

Starting with version 1.1, I get an error when calling Tuple[float, ...]'s __new__.

To Reproduce

from typing import Iterable, Tuple


class Foo(Tuple[float, ...]):
    def __new__(cls, values: Iterable[float]) -> Foo:
        return tuple.__new__(cls, map(float, values))

Expected Behavior

This should not be rejected by mypy (and it wasn't until version 1.1.1)

Actual Behavior

Starting with mypy 1.1.1, mypy complains with the following error

test.py:8: error: Value of type variable "Self" of "__new__" of "tuple" cannot be "Foo"  [type-var]

Remark
Changing tuple.__new__ to super().__new__ makes mypy complain (both mypy version 1.1.1 and 1.0.1) with

Argument 1 to "map" has incompatible type "Type[float]"; expected "Callable[[float], _T_co]"

Your Environment

• Mypy version used: 1.1.1 and 1.0.1
• Mypy command-line flags: none
• Mypy configuration options from pyproject.toml:

  [tool.mypy]
  
  [[tool.mypy.overrides]]
  module = "pandas.*"
  ignore_missing_imports = true

• Python version used: tested on 3.8 and 3.11

[AlexWaygood]

Probably due to this change in typeshed, where we moved from using a TypeVar in tuple.__new__ to using typing_extensions.Self: https://github.com/python/typeshed/pull/9694/files#diff-1580ddf7dc331234b0845ffb953b6f7a5f1e9afa15048ebc0762226a08f194b4R915-R916

That shouldn't make a difference to mypy's interpretation of your code, though, if mypy has the correct handling of typing_extensions.Self.

[AlexWaygood]

Cc. @ilevkivskyi as the person who implemented typing.Self.

If need be, we could maybe revert the change to tuple.__new__ in typeshed, but it would make it inconsistent with all the other __new__ methods in typeshed. I'm also not sure I'd want to do that unless we were sure this was a tuple-specific problem that didn't affect any other classes.

[ilevkivskyi]

This passes without errors on current master.