[steveklabnik]

> I really need to look in detail at how Rust enforces type-safety of Result<T,E>.

Basically, you can't use it as a T or an E; you have to process it in some way first. Basically, if you're familiar with Either, you know the whole story, it is the same. We originally had Either, then someone made Result, people always reached for Result over Either, so at some point, we axed Either. There is https://crates.io/crates/either though too.