- var_dump: documentation ( source)
<?php
interface ShipInterface {}
abstract class AbstractShip implements ShipInterface {}
class ShipOnlyAbstract extends AbstractShip {}
class ShipWithInterface extends AbstractShip implements ShipInterface {}
$shipOnlyAbstract = new ShipOnlyAbstract();
$shipWithInterface = new ShipWithInterface();
var_dump($shipOnlyAbstract instanceof AbstractShip);