[sv-ec] Query regarding illegal bins

Hi

I have a query regarding 'iff' with illegal bins .

Consider the following example:

coverpoint a {
  bins b1[] = {0, 1, 2, 3};
  illegal_bins il_bins = {0} iff x+y;  // Note guard expression
}

Now, as per LRM, bins are effective only when guard expression
evaluates to true. I believe this will apply for 
illegal_bins/ignore_bins. If
that is the case, values 0 will only be ignored iff "x+y"
is true while sampling. Now, it may happen that value 0 is ignored
during one sampling event (x+y true) and not ignored (x+y false)
during another sampling event.

In such scenario, LRM does not specify how to calculate the final coverage.

Thanks
Abhishek