Swift does have borrow checking: https://www.swift.org/blog/swift-5-exclusivity/ https://www.swift.org/blog/swift-5-exclusivity/ Basically the difference is th

Swift does have borrow checking: https://www.swift.org/blog/swift-5-exclusivity/ https://www.swift.org/blog/swift-5-exclusivity/ Basically the difference is that Swift's is more implicit, happens more at runtime, and it will make some programs work via copy-on-write that Rust would reject. So that's obviously more limiting. It's more flexible when you can allocate memory freely, but it doesn't work if you can't.