diff --git a/app/controllers/concerns/notes_actions.rb b/app/controllers/concerns/notes_actions.rb
index 3aa608c4792..048381a4d15 100644
--- a/app/controllers/concerns/notes_actions.rb
+++ b/app/controllers/concerns/notes_actions.rb
@@ -109,7 +109,7 @@ module NotesActions
             discussion_html: discussion_html(discussion)
           )
 
-          attrs[:discussion_line_code] = discussion.line_code if discussion.is_a?(DiffDiscussion)
+          attrs[:discussion_line_code] = discussion.line_code if discussion.diff_discussion?
         end
       end
     else