A few years ago, on a whim, I wrote YAIOUOM. YAOIOUM was a static analyzer for Rust that checked that the code was using units of measures correctly, e.g. a distance in meters is not a distance in centimeters, dividing meters by seconds gave you a value in m / s (aka m * s^-1). YAIOUOM was an example of a refinement type system, i.e. a type system that does its work after another type system has already done its work. It was purely static, users could add new units in about one line of code, and...