This doesn't really have much to do with the runtime. Certainly with a GC, programming would be easier, but I'm really talking about abstractions within the language. Rust already has language-integrated support for the Result monad. Rust doesn't have a general `do` syntax, but it has `?` which has made programming with the Result monad much easier. Can we think about the continuation monad and arrive at a new syntax that can ease this style of programming?
i don't really know Rust apart from some curious onlooking, but afaik expressing monads (i.e. the Monad typeclass) in Rust is tricky – something to do with the lifetimes of closures and the objects they close over, i think. ([Idiomatic Monads in Rust] probably touches on that). it might be possible to just build it into the language a la Result or async/await though.