It's doable to keep using pointers instead of indices- they just all have the lifetime of the vector and you can freely follow them around. This does prevent r

It's doable to keep using pointers instead of indices- they just all have the lifetime of the vector and you can freely follow them around. This does prevent resizing the vector, but you can get around that by using a different arena that allocates in chunks rather than reallocating (and thus doesn't require a unique reference for .insert).