Would upcasting from derived to base pointer and downcasting the base pointer to derived class pointer lose access to the derived class members?

SystemVerilog
1

Dear Verification experts, i have a question about casting in System Verilog.

suppose there is a base class

class base_transaction extends uvm_sequence_item;
    rand bit[7:0] addr, data;
    ...
endclass: base_transaction

and a derived class

class derived_transaction extends base_transaction;
    rand bit[7:0] opcode;
    rand int size;
...
endclass: derived_transaction

and handles to both class types

...
base_transaction basep = new;
derived_transaction derivedp = new;
derived_transaction new_derivedp = new;
...

it is legal to assign the ‘derivedp’ to the base pointer. But now using the base_pointer we cannot access ‘opcode’ and ‘size’.
suppose there arises a need to downcast basep to derivedp by doing cast$(new_derivedp, basep) will i be able to access ‘opcode’ and ‘size’ of the transaction using the ‘new_derivedp’ pointer?
or would 'new_derivedp’not be able to access the derived class members since it was downcasted from a base_pointer?

2

In reply to bbhushan:

No, you don’t lose access. There is just one handle to an object. When you downcast or upcast, you are just copying the handle from one class variable to another, nothing happens to the object. What you have access to is solely dependent on which class variable you are doing the referencing from.