Right but specifically it’s about being able to violate certain invariants you can’t otherwise and that’s it. Namely * Call unsafe functions * do memory alias

Right but specifically it’s about being able to violate certain invariants you can’t otherwise and that’s it. Namely * Call unsafe functions * do memory aliasing * change the lifetime the compiler sees That’s about it. The syntax and rules otherwise are still rust and violating those rules (eg aliasing in a way not allowed by rust) still results in UB. This can surprise some rust people even within popular crates and stdlib