--TEST--
Bug #72543.1 (different references behavior comparing to PHP 5)
--FILE--
<?php
$arr = [];
$arr[0] = null;
$ref =& $arr[0];
unset($ref);
$arr[0][0] = $arr[0];
var_dump($arr);
?>
--EXPECT--
array(1) {
  [0]=>
  array(1) {
    [0]=>
    NULL
  }
}