Reducing Raw Pointer Footguns: Preventing Reference Aliasing Violations at Compile Time

Aren't .mutable_reference() and .immutable_reference() just piggy-backing off of Rust's normal & and &mut semantics, just applied to guard instead of a? It doesn't look like your compile-time checks add anything beyond & and &mut.

Also.... just looking around, a lot of the methods you wrote are just mem::transmute in a "safe" trench coat. (That is, they're unsound. Size and align are far from the only aspects of a type that matter.)

Taking a step back and looking at the big picture, even if you solve those problems , your desired goal (compile-time errors for aliasing violations) is impossible in general. There is simply some information that you cannot know until runtime, and tools like Miri exist to test for UB, including aliasing violations, at runtime.

The purpose of raw pointers is to be used in places where compile-time checks are overly restrictive.

Granted, with a sufficiently complicated type system and sufficiently verbose annotations, you probably could encode a lot more invariants into the type system for compile-time checks. But speaking from experience as somebody who does very complicated manipulation of lifetimes, unsafe traits, higher-kinded trait bounds, etc... encoding too many invariants into the type system becomes a massive hassle that brushes against the edges of what's possible in Rust, and I'd imagine that most people aren't willing to deal with all that, all in exchange for... moving relatively-simple unsafe code into an overengineered system which likely uses plenty of unsafe internally? Probably a bit anticlimactic, even if it can be useful to remove unsafe from downstream code.

IMO, the best way to reduce the footguns associated with raw pointers is to better teach people Rust's "operational semantics". Piecing together a good mental model of how unsafe Rust works is currently... difficult. You have to do a lot of searching for information yourself, on random docs and forums and conversations.