- var_dump: documentation ( source)
- array_replace_recursive: documentation ( source)
<?php
$one = [1];
$two = [42];
$data = [
['k' => &$one],
['k' => &$two],
];
var_dump($data[0]['k'][0], $data[1]['k'][0]);
array_replace_recursive($data[0], $data[1]);
var_dump($data[0]['k'][0], $data[1]['k'][0]);