I have not encountered anything broken, aside from maybe binary app docstring stuff (e.g., automated example testing).

On the contrary, everything seems precise, reliable, and trustworthy. That's the thing to really like about Rust -- you can be pretty much fearless in it. It's just difficult. I die a bit in time any time I have a return type that looks like Box<dyn Fn(&str) -> Result<Vec<String>, CustomError>> or some shit . Honestly, the worst thing about Rust is probably that you have to manually specify heap vs stack when the compiler could easily make those determinations itself 99% of the time based on whether something is sized.