Recursive search

function array_search_path_recursive(array $haystack, $needle) {
    foreach ($haystack as $key => $value) {
        if (is_array($value)) {
            $result = array_search_path_recursive($value, $needle);
            if ($result !== false) {
                return $key . '->' . $result;
            }
        } elseif ($value === $needle) {
            return $key;
        }
    }
    return false;
}