Online PHP editor | vld for ZYcEZ

<?php error_reporting(E_ALL | E_STRICT); ini_set('display_errors', '1'); class O { protected $x; public function xy() { } } class SO { public function xoapapa() { } } class A { public function one(O $u) { } } class B extends A { public function one(SO $u) { } } $b = new B(); echo 'X';