The possible checks to confirm an FS reference is valid for a target CAS: 1. check if the CAS containing the FS reference is a valid view in the target CAS. 2. see if 0<FSaddr<top_of_FSheap for target CAS 3. if #2 is valid, see if FSheap[FSaddr] is a valid Type code
As said, still not a 100% guarantee. Not sure if all paths to setting an FS-ref go thru one place where such checks could be easily done. If so, pretty easy to implement and then one could do some comparative performance tests to see how much of a penalty is introduced. Eddie
