- class_alias: documentation ( source)
<?php
interface NewI {}
class_alias('NewI', 'OldI');
class C1 implements NewI {}
class C2 implements OldI {}
function fn(NewI $i) { echo "New: Success!\n"; }
function fo(OldI $i) { echo "Old: Success!\n"; }
fn(new C1);
fn(new C2);
fo(new C1);
fo(new C2);