diff --git a/web/edit_room.php b/web/edit_room.php
index 350ca6d4a2..4285e5216b 100644
--- a/web/edit_room.php
+++ b/web/edit_room.php
@@ -139,7 +139,7 @@ function get_fieldset_errors(array $errors) : ElementFieldset
 }
 
 
-function get_fieldset_general($data)
+function get_fieldset_general(array $data) : ElementFieldset
 {
   global $auth;