Comment by steveklabnik

I fully agree that there are similarities here. But we disagree about some of the details.

> you have essentially zero protection in Rust that helps you with finding Node-s that have been used for something else etc.

The most obvious technique is generations. You can of course do that in Zig as well.

> if you do use-after-free on a page claimed by the OS,

This assumes that you're working in the context where there is an OS. That isn't always the case. Also, there are other cases than just use-after-free: for example, compilers will optimize around null pointers being UB, which can cause other problems, whereas an index of zero does not get the same treatment.

But also, again: Zig does not use malloc for its ASTs, as far as I know. It uses lists and indices. I haven't literally read the code lately myself, but I would be surprised if they went back to malloc'ing individual nodes.