Online PHP editor | refs for m0pls

<?php error_reporting(E_ALL); interface Animal {} class Cat implements Animal {} class Shelter { function adopt(Animal $a) {} } class CatShelter { function adopt(Cat $a) {} } $cat = new Cat; $shelter = new Shelter; $shelter->adopt($cat); $catShelter = new CatShelter; $catShelter->adopt($cat);