Description:
------------
The following test code causes PHP to exit with a segmentation fault.

Test script:
---------------
<?php
register_shutdown_function(function () {
        $hookInfo = [function () {}];
        $hooks[][] = [$hookInfo];
});

$options = [
    'sort' => []
];
$defaultOption = ['sort' => []];

$sort = &$options['sort'];
$sort['direction'] = 'asc';

$val = array_merge($defaultOption, $options);
extract($val);

print_r($val);


Expected result:
----------------
Array
(
    [sort] => Array
        (
            [direction] => asc
        )

)

Actual result:
--------------
Array
(
    [sort] => Array
        (
            [direction] => asc
        )

)
Segmentation fault: 11