Type narrowing on object attribute with match statement doesn't apply

[AiroPi]

The bug
It seems that doing a "type checking" with the object UI in pattern matching seems to not work properly.
Attribute match is not considered.

Code

class Test:
    def __init__(self, a: int | str):
        self.a: int | str = a

test = Test(5)

match test:
    case Test(a = int()):
        print(test.a + 3)
    case Test(a = str()):
        print(test.a + "3")

Expected behavior
By doing a match with Test(a = int()), python will check test is of type Test AND test.a is of type int.
But mypy "only assert" that test if of type Test. It keep the type int | str for test.a.

Reproduce :
On mypy-playground :
https://mypy-play.net/?mypy=latest&python=3.11&gist=6f05124abd1ef68032d59651a7d5c6c3

[erictraut]

For reference: microsoft/pyright#4775

[cdce8p]

This should be fixed with #19736.