Type hint null

diff --git a/wcfsetup/install/files/lib/util/ArrayUtil.class.php b/wcfsetup/install/files/lib/util/ArrayUtil.class.php
index 431c4fc82fcbbaa69387e82f37d99e27a31e3545..1400d3fce890c113f623d51f7201971e4e4c9f1e 100644 (file)
--- a/wcfsetup/install/files/lib/util/ArrayUtil.class.php
+++ b/wcfsetup/install/files/lib/util/ArrayUtil.class.php
@@ -1,7 +1,7 @@
 <?php
 namespace wcf\util;
-use wcf\system\Callback;
 use wcf\system\exception\SystemException;
+use wcf\system\Callback;
 
 /**
  * Contains Array-related functions.
@@ -203,7 +203,7 @@ final class ArrayUtil {
         * @param       callable        $callback
         * @return      boolean
         */
-       protected static function compareHelper($method, array $array1, array $array2, Callback $callback) {
+       protected static function compareHelper($method, array $array1, array $array2, Callback $callback = null) {
                // get function name
                $function = null;
                if ($method === 'value') {