Decorator with constrained TypeVar specializes to first constraint

Bug Report

Changing the order of constraints of TypeVar T changes whether or not mypy passes. The wrapped method always gets narrowed to whatever the first constraint type is set to.

To Reproduce

from collections.abc import Callable
from typing import TypeVar, reveal_type


T = TypeVar("T", str, bytes)  # fails
# T = TypeVar("T", bytes, str)  # passes

def decorator(fn: Callable[[T], T]) -> Callable[[T], T]:
    def wrapped(data: T) -> T:
        return fn(data)
    return wrapped

@decorator
def process(data: T) -> T:
    return data

b: bytes = b"test"
result = process(b)

Or see mypy playground: https://mypy-play.net/?mypy=latest&python=3.12&gist=12fd2e05764d26a16cd1d16a10897671

Expected Behavior

Ideally pass for both versions, or consistently fail regardless of the constraint order.
On pyright playground the revealed types match my expectations and pass with either TypeVar order

Actual Behavior

mypy passes or fails depending on TypeVar constraint order, or the data input type

Your Environment

Same behavior with all tested mypy versions (1.6.0 .. 1.19.1) and python 3.11+

まず、issue にある decorator と制約付き TypeVar の最小再現コードを実行し、次に、mypy が制約の特殊化とラップされた callable をどのように処理しているかを追跡します。TypeVar の制約の順序に結果が依存しなくなり、両方の制約順序をカバーするテストがあれば完了です。