Earlier quoted context omitted.
Even Rust has an unsafe subset. There's a meaningful question about how to make such an unsafe language as easy and comfortable to use as possible, and Zig is a decent answer to that particular question. The libraries Zig ships with are especially relevant here, rather than the core language per se: Rust's library facilities are outright terrible to write unsafe code with, because the usual requirements of safe code…
Rust's library facilities are excellent for writing unsafe code with. Rust is very precise about which safety invariants must be upheld by which APIs, and does an excellent job documenting these, an excellent job at linting against improper usage of these APIs, and an excellent job leveraging the type system to reduce the need for unsafety in the first place. Writing unsafe Rust does indeed require its own degree of…
The point of unsafe Rust is to "leave no room for a lower-level language". When writing lower-level facilities it's not uncommon at all to have to resort to unsafe. In practice, relying on the idiomatic standard library support within an unsafe block that might be breaking Safe Rust invariants is almost a sure way of shooting oneself in the foot as soon as the library function is doing anything more complicated than taking a pure value as input and returning a value as output.