1--TEST-- 2Return type covariance error 3--FILE-- 4<?php 5interface foo { 6 public function bar() : foo; 7} 8 9interface biz {} 10 11class qux implements foo { 12 public function bar() : biz { 13 return $this; 14 } 15} 16--EXPECTF-- 17Fatal error: Declaration of qux::bar(): biz must be compatible with foo::bar(): foo in %s on line %d 18