False positive W0613 with keyword only argument

[DevinShanahan]

Bug description

Using a keyword-only argument is triggering a W0613(unused-argument) warning where it is not occurring if the (unused) argument is a keyword argument. Below, B.add does not issue the warning, but D.add does.

kwoa.py

# pylint: disable=C*,R*
class A:
    def add(self, a, b=0):
        return a + b

class B(A):
    def add(self, a, b=0):
        return None

class C:
    def add(self, a, *, b=0):
        return a + b

class D(C):
    def add(self, a, *, b=0):
        return None

Configuration

No response

Command used

pylint kwoa.py

Pylint output

************* Module kwoa
kwoa.py:16:24: W0613: Unused argument 'b' (unused-argument)

Expected behavior

I believe there are two possibilities here but I had been operating under the assumption that this warning would not occur for D.add given that is not the behavior for B.add. The other option is that a warning should also be issued B.add.

Pylint version

pylint 2.12.2
astroid 2.9.0
Python 3.9.5 (default, May 18 2021, 12:31:01) 
[Clang 10.0.0 ]

OS / Environment

No response

Additional dependencies

No response

[jacobtylerwalls]

Thanks for the report. Based on this comment I think you are correct that this is not supposed to warn. I have a diff for astroid that fixes it and hope to PR it soon.

[jacobtylerwalls]

PR adding the regression test should also simplify this to just argnames(): 01cc02d5e