Bug report

public function update(object $entity): void
{
    assert(method_exists($entity, 'getId'));

    $class = $entity instanceof Proxy
        ? get_parent_class($entity)
        : get_class($entity);
    assert(is_string($class));
}

phpstan gives the following false positive error on is_string call, when method_exists is called on the original object beforehand:

Call to function is_string() with false will always evaluate to false.

$class is not always false in this case

Code snippet that reproduces the problem

https://phpstan.org/r/2435eca1-a03a-450a-9927-8d99140c0048 - has error
https://phpstan.org/r/17c8150b-569a-430a-b02e-1ddaa2313016 - method_exists commented out -> no errors
https://phpstan.org/r/5bbd636c-ee9d-4a1c-b832-2f3b47a14d6a - method_exists called afterwards -> no errors

Expected output

no errors