Indeed int2ptr is the "evil" operation. If we banned it, we could get rid of all this "exposed" stuff and ptr2int would be fine. However, in order to make int2p

Indeed int2ptr is the "evil" operation. If we banned it, we could get rid of all this "exposed" stuff and ptr2int would be fine. However, in order to make int2ptr work, we have to also make ptr2int a bit more complicated. That's what the example shows: removing a ptr2int introduced UB into the program. Rust now (experimentally) has an `ptr.addr()` operation that is like ptr2int without the "expose" part, i.e., the resulting integer cannot be cast back but still used for other purposes.