typestates are great, but in rust i wonder if it would be more ergonomic and easier to get right if it was officially a feature instead of a pattern you have to implement...?
Amazingly, typestates used to be a headline feature of Rust, in the very, very, very old days. Like, "Wow, Rust is the language that's going to make typestates mainstream!" was a thing people thought when seeing it.
Eventually it was removed. https://pcwalton.github.io/2012/12/26/typestate-is-dead.html