Supposedly Swift 4 is introducing an optional borrow-checker. Types can opt-in and you get the same kind of lifetime guarantees and semantics as Rust. If you do

Supposedly Swift 4 is introducing an optional borrow-checker. Types can opt-in and you get the same kind of lifetime guarantees and semantics as Rust. If you don't opt-in you get copying for value types and reference counts for reference types. I'm curious how either approach will work out in the long run. I understand why Rust made the decisions it did wrt ditching built-in GC/non-GC support but it will definitely hamper its adoption for writing GUI applications. If Swift manages to thread the needle in supporting systems-level / kernel programming with borrow-checked types while not imposing that mental and maintenance cost on GUI apps it will be an amazing thing. In any case it is exciting to see high-level languages with memory safety proving you can have something much better than C without going full-on virtual machine, runtime, and JIT.