3v4l.org

run code in 300+ PHP versions simultaneously
<?php class A {} class B extends A {} class Foo { public function test(B $a) { var_dump(get_class($a)); } } class Bar extends Foo { public function test(A $a) { parent::test($a); } } (new Foo)->test(new A); (new Foo)->test(new B); (new Bar)->test(new A); (new Bar)->test(new B);

preferences:
51.47 ms | 402 KiB | 5 Q