In reply to chrisspear:
But then the sequence and sequencer also need to be specialized with the derived type.
I believe as long as ::
- Specialization of driver - sequencer ( via TLM ) are of base REQ type
- Argument to start_item , finish_item in the sequence is Cast Compatible with REQ type of sequencer
- and we override the base-type with extended-type from Top component like test class
the TB need not be changed i.e using the base class ( REQ type parameter ) specialization for driver , sequencer and sequence it would still work
EDIT : Dynamic cast logic would be required within driver to access extended class properties .