php – SplObjectStorage是否会在对象仍然附着时破坏内存泄漏引

$storage = new SplObjectStorage();
$x = new stdClass();
$y = new stdClass();
$storage->attach($x);
$storage->attach($y);
$storage = null; 
// did not explicitly detach $x and $y... does $storage's destruction do it?
// or do the zval counts on $x and $y now off by one?
$x = null;
$y = null;
// at this point,are there two dangling references to $x and $y,// simply because $storage did not dereference from them before destroying itself?