match-case: false positive [unbound-name]

[randolf-scholz]

Describe the Bug

from typing import assert_type

def test(x: int | None, y: int | None) -> None:
    match x, y:
        case None, None:
            raise ValueError
        case int(m), None:
            u = m * 3
            v = m
        case None, int(n):
            u = n
            v = n // 3
        case _, _:
            raise ValueError

    assert_type(u, int)
    assert_type(v, int)

ERROR sandbox.py:16:17-18: `u` may be uninitialized [unbound-name]
ERROR sandbox.py:17:17-18: `v` may be uninitialized [unbound-name]

Sandbox Link

https://pyrefly.org/sandbox/?project=N4IgZglgNgpgziAXKOBDAdgEwEYHsAeAdAA4CeS4ATrgLYAEALqcROgOZ0Q3G6UN2o4cGHwD6TYjAA66GZhhhG8BgAp8iTun4AfOgDlc6GABo6pDax37DMAJR0AtAD5rRxDLqe6NVAwDGABZ0%2BKbmHl4RfoIwriax7ugRSV6UqBDCdABqqFAArjAAopTUlOHJURmWKjS2pgZuZcleuXQAvN50AFR0AMyNTXQAbm3e-V4VMfVxVei2CQMRLe2yiQuew8t0APRbvWOeE3SipqLza3Sp6THZeYXFvDKNgsJiEjAquaaWtk9CIgziZjvQZfLS2EDGEBkSgKKCkQgMWhQCgAYjoAAVSDCwHC6GgsHh8HQ-IZIGxcqkGBBDIQZGiAMowGIBBgMYhwRA7aGw%2BG8NhbGDoLaYXB%2BOBbEnoMkU3zUoV0MC8ASDNJQVDYWDE0kQcmUuV0XDEKmGOC09BkBgBQwOQYiOD69pSEA9QgARgATE6ZABtEQlOAAXRkuXQXB4fBgmAcmAgML8VNtIwA5Dr0LwYEmZGmGA4YQBHXKxyMOADWMFIDlQfj88DgyYA7qhKOhM%2BgQABfSFVhMwABi0BgFHxOAIJHI7aAA

(Only applicable for extension issues) IDE Information

No response

[randolf-scholz]

PS: The version below succeeds, so I think it is because pyrefly doesn't realize that case _, _: is a catch all when matching tuple[T1, T2]

def test(x: int | None, y: int | None) -> None:
    match x, y:
        case None, None:
            raise ValueError
        case int(m), None:
            u = m * 3
            v = m
        case None, int(n):
            u = n
            v = n // 3
        case _:
            raise ValueError

    assert_type(u, int)
    assert_type(v, int)

https://pyrefly.org/sandbox/?project=N4IgZglgNgpgziAXKOBDAdgEwEYHsAeAdAA4CeS4ATrgLYAEALqcROgOZ0Q3G6UN2o4cGHwD6TYjAA66GZhhhG8BgAp8iTun4AfOgDlc6GABo6pDax37DMAJR0AtAD5rRxDLqe6NVAwDGABZ0%2BKbmHl4RfoIwriax7ugRSV6UqBDCdABqqFAArjAAopTUlOHJURmWKjS2pgZuZcleuXQAvN50AFR0AMyNTXQAbm3e-V4VMfVxVei2CQMRLe2yiQuew8t0APRbvWOeE3Si82t0qekx2XmFxbwyjYLCYhIwKrmmlrYPQiIM4syvQYfLS2EDGEBkSgKKCkQgMWhQCgAYjoAAVSFCwDC6GgsHh8HQ-IZIGxcqkGBBDIQZCiAMowGIBBgMYhwRA7SHQ2G8NhbGDoLaYXB%2BOBbInoElk3yUgV0MC8ASDNJQVDYWCE4kQUnkmV0XDECmGODU9BkBgBQwOQYiOC69pSEA9QgARgATA6ZABtEQlOAAXRkuXQXB4fBgmAcmAgUL8FOtIwA5Fr0LwYAmZCmGA4oQBHXLR8MOADWMFIDlQfj88DgiYA7qhKOh0%2BgQABfcEVuMwABi0BgFFxOAIJHIraAA