Guilty as charged, and honestly, I wish I had a good mechanism/function call to separate "I'm just being lazy here, this is a TODO" from "actually, this should never happen.
.map_err(|_| unimplemented!()).unwrap()
or something. (I hope you get the gist of that, as I'm 99% sure that code doesn't compile. Error(E) -> !, Ok(T) -> T)