3v4l.org

run code in 300+ PHP versions simultaneously
<?php class Node { public $next; public $previous; } $first = new Node(); $first->next = $first; $new = new Node(); $new->previous = $first; $new->next = $first; $first->previous = $new; var_dump($first == $new);

preferences:
25.64 ms | 404 KiB | 5 Q