I feel like making programming languages is an area where Rust can really make use of its advantages without the commonly cited pitfalls. You won't be dealing with any I/O other than filesystem APIs (outside of making a standard library or something), so you can entirely avoid needing to decide whether to use async or not, and you can go pretty far just using value types and copying without it being a likely performance bottleneck. Most languages won't use much concurrency in their compiler either; Rust itself parallelizes builds per crate with Cargo, which invokes rustc separately for each compilation unit.

I'm sure some people might read all this and conclude that they might as well just use OCaml or Haskell, and those are really good languages for compilers too! The tooling and ecosystem make Rust more appealing to me personally though, and I suspect that there are probably others who would find Rust's ecosystem a bit more approachable as well.