Yes, I've written a few unsafe-focused crates [0], some of which have been modified & merged into the stdlib [1] [2] exposing them to the fringe edge-cases of Rust like strict provenance.

IMO, Rust is good for modeling static constraints - ideal when there's multiple teams of varying skill trying to work on the same codebase, as the contracts for components are a lot clearer. Zig is good for expressing system-level constructs efficiently: doing stuff like self-referential/intrusive data structures, cross-platform simd, and memory transformations is a lot easier in Zig than Rust.

Personally, I like Zig more.

[0] https://crates.io/users/kprotty

[1] https://github.com/rust-lang/rust/pull/95801

[2] https://github.com/rust-lang/rust/blob/a63150b9cb14896fc22f9...