In reply to Frank.Wang:
It will help to run a quick test in your system to confirm what cgales said: I covered this in our DVCon US advanced UVM Debug tutorial (Slides at: http://www.go2uvm.org/2016/07/advanced-uvm-tutorial-from-dvcon-us-2016-slides-now-available/ See #12 onwards). In your case I would suggest using f.print(.all_types(2)) to ensure you don’t miss any.
Will appreciate if you share your findings here (perhaps without the tool name if you care to suppress that information).
Regards
Srini
www.go2uvm.org