Online PHP editor | output for gcKTm

<?php class A {} class B extends A {} class C extends B {} interface InterfaceTest { public function foo(B $p); } abstract class AbstractTest { public abstract function foo(B $p); } // class TestAbstractContravariance extends AbstractTest { // public function foo(A $p) {} // } class TestAbstractCovariance extends AbstractTest { public function foo(C $p) {} } class TestInterfaceContravariance implements InterfaceTest { public function foo(A $p) {} } class TestInterfaceCovariance implements InterfaceTest { public function foo(C $p) {} }