Nope. Rust stabilized strict provenance over a year ago. Some details about aliasing aren't tied down, but so long as you can obey the strict provenance rules you're golden today in Rust to hide flags in pointers etc.
https://blog.rust-lang.org/2025/01/09/Rust-1.84.0/#strict-pr...
But LLVM's optimizations aren't sound and this affects Rust too.