[1.20 regression] unreachable regression with generic Callable

[dpinol]

Bug Report

Since mypy 1.20.0, a comparison between 2 generic callables may cause "Statement is unreachable"

To Reproduce

from typing import Callable

def identity[T](x: T) -> T:
    return x

def msg[T,S](cmp_property: Callable[[T], S]) -> None:
    if cmp_property == identity:
        return

Expected Behavior

Mypy should not report any error.

Actual Behavior

scpytools/kk.py: note: In function "msg":
scpytools/kk.py:10: error: Statement is unreachable  [unreachable]
            return
            ^~~~~~

Your Environment

• Mypy version used: mypy 1.20.0 (compiled: yes)
• Mypy command-line flags: mypy --warn-unreachable
• Mypy configuration options from mypy.ini (and other config files): No config files
• Python version used: 3.14.2

[hauntsaninja]

Thanks, changes in 1.20 surface a pre-existing deficiency in is_overlapping_types, will look more...