diff --git a/tpl/macro.twig b/tpl/macro.twig
index 2d63ad7..92ae6bc 100644
--- a/tpl/macro.twig
+++ b/tpl/macro.twig
@@ -411,7 +411,8 @@ public class {{o.name}} : IRpc
 
       if(old < item)
       {
-        removed.Add(old.MakeId());
+        if(removed != null)
+          removed.Add(old.MakeId());
         old_i++;
         has_diff = true;
       }