1--TEST-- 2Cloning uninitialized IntlDateFormatter 3--EXTENSIONS-- 4intl 5--FILE-- 6<?php 7 8class A extends IntlDateFormatter { 9 function __construct() {} 10} 11 12$a = new A; 13try { 14 $b = clone $a; 15 var_dump($b); 16} catch (Throwable $e) { 17 echo $e::class, ': ', $e->getMessage(), PHP_EOL; 18} 19?> 20--EXPECT-- 21Error: Cannot clone uninitialized IntlDateFormatter 22