Description:
------------
Value 200 shouldn't appear on array $p

And it gives different results on php5/7

Test script:
---------------
<?php

$p = array(array());
array_push($p[0], array(100));

$c = array_merge($p, array());
$c[0][0] = 200;

print_r($p);


Expected result:
----------------
Array
(
    [0] => Array
        (
            [0] => Array
                (
                    [0] => 100
                )

        )

)


Actual result:
--------------
Array
(
    [0] => Array
        (
            [0] => 200
        )

)