[thinkharderdev]

> doesn't mean you're not stomping on in-bounds neighboring data

I don't see how you would do that in safe rust though. The point of the arena would just be to solve the lifetime issue. It just moves the ownership problem one level higher. Instead of having circular ownership in a linked list, all linked list nodes are owned by the arena and hence have the same lifetime as the arena.

[mwkaufma]

It's not just linked lists. From the article:

> The next step of course is to write your own equivalents of malloc and free to allocate and deallocate objects within the arena.

A logic bug in that "allocator" - which are plain indices and not covered by borrow checking - could 100% stomp memory.

[thinkharderdev]

Sure, any program can have bugs. The point though is that it is "just a bug" and not UB.