Hacker News Reader

I have never even heard of the linked repo, and it does not appear to be overly popular. Nor have I ever heard of "witness types" or seen code that attempts to make use of them. And no, any new borrow checker would not require some new approach to iterators. This entire comment reads like a non sequitur. Where on Earth did you get any of this from?

The project you've linked warns you that it is in its very early stage and that you should only use it as an early adopter.

C++98 (and older) is still widely used in embedded systems.