match narrowing fails when the operand is an await expression #17230

from typing import assert_never

async def fn() -> int | None:
    return None

async def foo() -> None:
    match await fn(): 
        case int():
            pass
        case None:
            pass
        case never:
            assert_never(never) # error: Argument 1 to "assert_never" has incompatible type "int | None"; expected "NoReturn"  [arg-type]
            
async def bar() -> None:
    a = fn()
    match await a: 
        case int():
            pass
        case None:
            pass
        case never:
            assert_never(never) # error: Argument 1 to "assert_never" has incompatible type "int | None"; expected "NoReturn"  [arg-type]
            
async def baz() -> None:
    match _a := await fn(): 
        case int():
            pass
        case None:
            pass
        case never:
            assert_never(never) # works!