C can't do provenance

> Yes, where the pointer came from is the whole point of provenance. That's because if the pointer came "from nowhere," or from an unrelated pointer, then on CHERI it will not have the correct metadata (or any metadata), and so dereferencing it will trap.

This can technically happen with "far" pointers on the 32-bit segmented x86 architecture. Simply reading or trying to create a pointer to an invalid segment can cause an exception.