Using TypeVar as typing for a function argument disables the --strict-equality check

Bug Report

When using a TypeVar as typing for a function parameter, the --strict-equality checks are no longer executed.

To Reproduce

from typing import TypeVar

T = TypeVar("T", int, str)


def a(x: T) -> None:
    1 == "a"


def b(x: int | str) -> None:
    1 == "a"

a(1)
b(1)

Playground: https://mypy-play.net/?mypy=master&python=3.10&flags=strict&gist=60fa0e9e47a0ed5683357b1fa2611477

Expected Behavior

I would expect both functions a() and b() to raise the comparison-overlap error.

Actual Behavior

Only function b() where there is no TypeVar used raises the comparison-overlap error.

Note that other, standard, mypy checks are executed and flagged in both functions.

Your Environment

• Mypy version used: Checked with multiple (1.4.1, 1.7.0, master branch)
• Mypy command-line flags: --strict or --strict-equality
• Mypy configuration options from mypy.ini (and other config files): -
• Python version used: 3.10, 3.11

Run the provided reproducer with --strict-equality and compare diagnostics for functions a() and b(). Trace mypy’s strict-equality handling for constrained TypeVar parameters; done means both comparisons report comparison-overlap, with regression coverage confirming the behavior.