The use of RC is orthogonal to the memory safety guarantees of Rust. The use of RC and safety checking of it is handled at compile time, and only the refcounting aspect is runtime.

RC is a form of declaring shared use and is a parallel to shared_ptr in C++.

And yes there are escape hatches for safety that you can explicitly put yourself in. MTE would catch those at runtime , but you would still have prevented a ton at compile time.

There are also escapes you can find yourself in with memory tagging too.

Also, did you really just create a new account (with an inflammatory name) to crap on Rust while still not being able to address the points in my comment?