Earlier quoted context omitted.
Rust will probably encompass most of these use cases eventually. Features like e.g. RC with efficient cycle collection as found in Nim, or generational regions as found in Vale, will simply be implemented as add-on crates in Rust, complementing the existing borrow checker.
There are some design decisions mean Rust can't work with generational references and regions, unfortunately. They're incompatible with their form of borrow checking. In Vale, each struct has a generation in theory, but they are often merged with their parent struct. It requires some pretty interesting logic which can't be implemented in Rust. Regions require truly immutable references, which Rust doesn't have. Their…
(Don't get me wrong, I'm quite fine with also focusing on hobbyist, proof-of-concept languages for potential improvements to developer productivity. But then I'll probably want a Pony.)