1--TEST-- 2call_user_func() should not use FUNC_ARG fetches 3--FILE-- 4<?php 5 6function foo(&$ref) { $ref = 24; } 7 8$a = []; 9call_user_func('foo', $a[0][0]); 10var_dump($a); 11 12?> 13--EXPECTF-- 14Warning: Undefined array key 0 in %s on line %d 15 16Warning: Trying to access array offset on value of type null in %s on line %d 17 18Warning: foo(): Argument #1 ($ref) must be passed by reference, value given in %s on line %d 19array(0) { 20} 21