>While we are many missing language features away from this being the case, the noalias case is also magic descended upon box itself, with no user code ever having access to it.

I'm not sure why the author thinks there's magic behind Box. Box is not a special case of `noalias`. Run this snippet with miri and you'll see the same issue: https://play.rust-lang.org/?version=stable&mode=debug&editio...

You don't see an assertion failure though because... dun dun dun it's UB.

`Box<T>` _does_ have an expectation that its inner pointer is not aliased to another Box (even if used for readonly operations). See: https://github.com/rust-lang/miri/issues/1800#issuecomment-8...)