[steveklabnik]

Rust tags every &mut T and every &T with the equivalent of restrict except for when the T transitively contains an UnsafeCell<T>. Types like Arc<T> and Rc<T> are built on top of UnsafeCell<T>.

Don’t use shared ownership? You get the semantics you want. It’s the norm for the vast majority of things.

[torginus]

Thanks for the answer, that sounds reassuring. I have another question, from what you said, it sounds like you remove restrict from the whol argument, but technically, afaict, the Rust borrow rules still prevent anything inside those structs getting aliased, with the exception of the stuff inside UnsafeCell<> (even with Rc<> the underlying value cannot be aliased, only the reference counter).

Does Rust/LLVM track aliasing to this degree, or is it all or nothing, like if you have a UnsafeCell anywhere, the whole type is excluded from restrict?

[steveklabnik]

I am not sure off the top of my head, to be honest. https://news.ycombinator.com/item?id=46616616 was a thread where I was talking about this sort of thing previously, you could probably adapt those code examples and get an answer.