Missing `static` modifier for the callback

diff --git a/files/lib/data/conversation/ConversationAction.class.php b/files/lib/data/conversation/ConversationAction.class.php
index d600dc64191f43c482f60b0234ec57a4ed552b38..649e8de3b090b6578b9c4cea8cc6c490d2dc77d5 100644 (file)
--- a/files/lib/data/conversation/ConversationAction.class.php
+++ b/files/lib/data/conversation/ConversationAction.class.php
@@ -919,7 +919,7 @@ class ConversationAction extends AbstractDatabaseObjectAction implements
             } else {
                 if ($conversation->participants > 1) {
                     $image = '<span class="icon icon48 fa-users"></span>';
-                    $usernames = \array_filter($conversation->getParticipantSummary(), function (User $user) {
+                    $usernames = \array_filter($conversation->getParticipantSummary(), static function (User $user) {
                         return $user->userID !== WCF::getUser()->userID;
                     });
                 } else {