1--TEST-- 2The default value is null in the parent class method's signature. 3--FILE-- 4<?php 5class MyDateTime extends DateTime 6{ 7 public static function createFromFormat(): DateTime|false 8 { 9 } 10} 11?> 12--EXPECTF-- 13Fatal error: Declaration of MyDateTime::createFromFormat(): DateTime|false must be compatible with DateTime::createFromFormat(string $format, string $datetime, ?DateTimeZone $timezone = null): DateTime|false in %s on line %d 14