1--TEST-- 2Enum must not implement Serializable indirectly 3--FILE-- 4<?php 5 6interface MySerializable extends Serializable {} 7 8enum Foo implements MySerializable { 9 case Bar; 10 11 public function serialize() { 12 return serialize('Hello'); 13 } 14 15 public function unserialize($data) { 16 return unserialize($data); 17 } 18} 19 20var_dump(unserialize(serialize(Foo::Bar))); 21 22?> 23--EXPECTF-- 24Deprecated: %s implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in %s on line %d 25 26Fatal error: Enum Foo cannot implement the Serializable interface in %s on line %d 27