Invalid X or Z in state expression value for constraint

In reply to dave_59:

Hi Dave,

 I am hitting the same issue, where I want to deliberately drive x's on a signal as per the specification and I want the x's driven on input-2 only for certain values of input-1. How can I achieve this ?

I declared the variables in the sequence as rand logic and randomizing the seq item using the “with” construct.

How can I drive x’s using some constraints? Is logic type not allowed to be used in constraints ? If yes, why is this restriction ?

Thanks,
Madhu