It was a simple example; whether a specific optimization applies is very tricky. We have to look at the details. When can Rust move or eliminate a binder? Does Rust support automatic parallelization? What happens if you use unsafe blocks to lie to their type and ownership system? I think many of the same issues will surface.
To be me, the interesting question is: What happens when you lie to the type (and effect or ownership) system?
To be me, the interesting question is: What happens when you lie to the type (and effect or ownership) system?