const again

[BCS]

totally random though: I'm designing a program and ran across a place where 
I want to say "this pointer shall never be dereferenced, it shall only be 
used as an identity" the idea being that I want to be sure that the code 
has no dependencies on anything under it. It would be used somthing like 
a key in a hash table but where the test is "same thing" not "equal things". 
What should this be implemented as? Does this have any place in the const 
system? Is there an existing clean solution?

I'm putting this out more as food for though than as a serious suggestion 
or request for thoughts on how to implement stuff in my case.