Exhaustiveness checks (assert_never) don't work with 2-tuple of enums

Bug Report

The code below fails to type check, but should succeed because it's exhaustive.

There are some possibly related issues, but I don't know if they are all the same bug, the other tickets tend to depend on Union which this does not: #16650 #15426 #12364

To Reproduce

Playground link: https://mypy-play.net/?mypy=latest&python=3.12&gist=0d21d288fce8aa13d3cc60f4e418960a

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from enum import Enum
from typing import assert_never

class A(Enum):
    A0 = 0
    A1 = 1

class B(Enum):
    B0 = 0
    B1 = 1

def test(a: A, b: B) -> bool:
    match (a, b):
        case (A.A0, B.B0):
            return True
        case (A.A0, B.B1):
            return True
        case (A.A1, B.B0):
            return True
        case (A.A1, B.B1):
            return True
        case _ as never:
            assert_never(never)

    return False

Actual Behavior

typecheck_test.py:26: error: Argument 1 to "assert_never" has incompatible type "tuple[A, B]"; expected "NoReturn"  [arg-type]

Your Environment

• Mypy version used: 1.8.0
• Mypy command-line flags: n/a
• Mypy configuration options from mypy.ini (and other config files): n/a
• Python version used: 3.11 (but also happens with 3.12 in playground link)

まず、リンクされた mypy playground またはローカルの mypy checkout で、提示された 2 つの enum のタプル例を再現します。次に、構造的パターンマッチングと assert_never の網羅性チェックの経路を調べます。例で互換性のない tuple[A, B] エラーが発生せずに型チェックを通過し、非網羅的なマッチに対する既存の動作が維持されれば完了です。