In reply to Prashant Soni:
Your code as written doesn’t compile in any of the four simulators on EDA Playground. Specifically, the arrays of verif_if and chk_intf in top_if are incorrect as they should be arrays of instances, which is not what is written.
I recommend using a parameter to verif_if to specify the instance_num instead of an int, as a parameter is a constant while a variable is not.