[adrianN]

Oh man, so I've been doing in wrong all the time. I always thought it would be a good idea to use the type system to its full capabilities and complained about the compiler for not adequately slapping my wrist when I obviously assign negative numbers to unsigned variables (a sign analysis is pretty simple to implement!).

[barrkel]

Yes, you have been doing it wrong all this time, and I'm fairly confident in this. Using the type system to its full capabilities is not in itself a natural good. Sign analysis doesn't help you with the problem, because the problem is that using unsigned types means opting into a different arithmetic, an arithmetic which is unnatural to most humans.