[codegen] Fix error for --incremental=param,debug

fixes #333

src/template/incremental/Notification.tt

@@ -235,7 +235,7 @@ $endif
   #resetCache
   #(signature)_handler.notifyDependencies();
   $if (TraceFlush)
-  state().trace().flushIncAttr($HostClass.this, "#signature", "", "");
+  $HostClass.this.state().trace().flushIncAttr($HostClass.this, "#signature", "", "");
   $endif
 }
 $endif