https://phpstan.org/r/f9752c92-46b6-4e7b-80b5-97b5c70ee802

I have a class hierarchy B < A < Base (abstract) and I want arguments of type Base to be treated as A|B so I can handle them like this:

function f(Base $v) {
    return match (true) {
         $v instanceof B => 'B',
         $v instanceof A => 'A',
    };
}

but I can't get this to work.
am I missing something or is this a bug?