- var_dump: documentation ( source)
- array_replace_recursive: documentation ( source)
- current: documentation ( source)
<?php
$one = [1];
$two = [42];
$arr_1 = ['k' => &$one];
$arr_2 = ['k' => &$two];
var_dump(current($arr1['k']), current($arr2['k']));
array_replace_recursive($arr1, $arr2);
var_dump(current($arr1['k']), current($arr2['k']));