Haskell and Idris and the like (other languages with a type system in the calculus of constructions) inarguably support a higher level of abstraction than Rust does, and are also “GC-obligate” languages. So your example is something of a red herring. I could say the same about Kotlin and Swift and Scala, none of which really have a strong story for static memory safety like Rust has, though it’s being considered for Swift. The only language that is reasonably complete that I could think to compare it to is ATS, which is far more complex as a result.