False override error with Unpack and TypedDict

[mharding-hpe]

Bug Report

When using Unpack and TypedDict in a child class method, mypy is giving a false override error.

To Reproduce

from typing import final, TypedDict, Unpack

@final
class Kwargs(TypedDict):
    a: int

class Parent:
    def harf(self, required_arg: str, a: int) -> None:
        pass

class Child(Parent):
    def harf(self, required_arg: str, **kwargs: Unpack[Kwargs]) -> None:
        super().harf(required_arg, **kwargs)

https://mypy-play.net/?mypy=latest&python=3.12&gist=78008ce1aa8f6b34a332ea34e2937efc

Expected Behavior

I don't think mypy should report an error. The Kwargs class is final, so it should not be subclassed, and it is total, so it should have all of its keywords.

Actual Behavior

main.py:12: error: Signature of "harf" incompatible with supertype "Parent"  [override]
main.py:12: note:      Superclass:
main.py:12: note:          def harf(self, required_arg: str, a: int) -> None
main.py:12: note:      Subclass:
main.py:12: note:          def harf(self, required_arg: str, *, a: int) -> None
Found 1 error in 1 file (checked 1 source file)

The * makes it seem like mypy thinks my subclass method allows for additional parameters that are not present in the parent method, but I don't see where it is getting that idea.

Your Environment

• Mypy version used: 1.13.0
• Mypy command-line flags: None (I reproduced it on the playground)
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.12

[erictraut]

Mypy is correct to generate an error here. The Parent.harf method has a parameter a that accepts both positional and keyword arguments, but you're attempting to override it with a method that accepts a only as a keyword argument.

You can fix the type error by changing Parent.harf to accept a only as a keyword argument, like this:

class Parent:
    def harf(self, required_arg: str, *, a: int) -> None:
        pass

[mharding-hpe]

Thank you so much for the prompt response! I very much appreciate it, and apologize for the false bug report