diff --git a/apps/user_ldap/lib/Group_LDAP.php b/apps/user_ldap/lib/Group_LDAP.php
index 96f1898c647..950f8bd3e4f 100644
--- a/apps/user_ldap/lib/Group_LDAP.php
+++ b/apps/user_ldap/lib/Group_LDAP.php
@@ -787,6 +787,7 @@ class Group_LDAP extends BackendUtility implements GroupInterface, IGroupLDAP, I
 	}
 
 	/**
+	 * @return array[]
 	 * @throws ServerNotAvailableException
 	 */
 	private function getGroupsByMember(string $dn, array &$seen = []): array {