DeVault: Announcing the Hare programming language

The pointer I got from malloc() for my 400 byte allocation, and the pointer malloc itself relies on for managing the heap after I free() it are not actually the same pointer even though on a typical modern CPU they're the same magic number in a CPU register.

The pointer I had comes with provenance given to it by malloc(), it's a pointer to my 400 byte allocation. If I add 390 to it, that's a pointer to the last 10 bytes of the allocation, and we're all fine. But if I add -16 to it, that's not a pointer to anything.

The pointer used by the allocator uses different provenance, it's a pointer into the heap, and you can totally add -16 to it, because that's just a different pointer into the heap and as such fine.