For what it's worth (and I intentionally didn't point this out in the parent), you can make a safe graph library in Rust with a typed arena (slightly less ergon

For what it's worth (and I intentionally didn't point this out in the parent), you can make a safe graph library in Rust with a typed arena (slightly less ergonomic and faster) or a refcounted smart pointer (slightly more ergonomic and slower). But this still does not validate your point, since the memory allocator is in many cases unsafe. On how to ensure correctness of the `unsafe` code: that was what we were doing with the entire C/C++ code for decades, so what's the problem? We could however concentrate on the much less amount of code if we were using safer languages.