diff --git a/src/hb-aat-layout-morx-table.hh b/src/hb-aat-layout-morx-table.hh
index 4a997eeca..aa7b6d90e 100644
--- a/src/hb-aat-layout-morx-table.hh
+++ b/src/hb-aat-layout-morx-table.hh
@@ -393,6 +393,7 @@ struct LigatureSubtable
 	    buffer->skip_glyph ();
 	    end--;
 	  }
+	  /* TODO merge_clusters / unsafe_to_break */
 
 	  match_length--;
 	  action_idx++;