You would encode that into types and expose a safe API. The usafe would still be local in scope. For example you might build an abstraction named ReadWriteMute

You would encode that into types and expose a safe API. The usafe would still be local in scope. For example you might build an abstraction named ReadWriteMutex that guarantees safe access at runtime. I don't see a scenario where this would impede performances. The invariants to validate are the same. But rust would guarantee that it is memory safe.