Constructor signature

gistfile1.php

<?php
interface Something{}

interface AnotherThing{}

class Foo{
	public function __construct(Something $thing){}
	public function foo(Something $thing){}}

// No problem.
class FooSomeChild extends Foo{
	public function __construct(AnotherThing $thing){}}

// Works, but PHP complains.
class FooAnotherChild extends Foo{
	public function foo(AnotherThing $thing){}}