3v4l.org

run code in 300+ PHP versions simultaneously
<?php namespace derp { class Foo {} class_alias('\derp\Foo', 'DerpFoo'); } namespace herp { use DerpFoo; class BetterFoo extends \derp\Foo {} class Derp { public function __construct(DerpFoo $foo) {} } $f = new Derp(new BetterFoo); }

preferences:
38.35 ms | 402 KiB | 5 Q