It’s not just restrict. Rust indeed does have much more strict rules that even though at first glance seem similar to C, the optimizer is allowed to do weird things if you violate a lot harder to understand rules. This has been very well documented.

For example, if I recall correctly it’s technically UB to cast to a *mut pointer unless the original variable was declared mut even if you have exclusive ownership over that object.

There was a fantastic blog post describing a lot of these nuances but I can’t find it.