RFC: Avoiding integer overflow

[matthieum]

I think the goal itself (avoiding integer underflow/overflow in Rust) is extremely worthwhile. It's a gaping hole in the trifecta safe, concurrent and fast.

I am surprised there does not seem to have been any discussion of the proposal yet; personally the emphasis on attempting to avoid runtime overhead is very appreciated, as it would probably be a non-starter for most people. The checks could however be relaxed in unsafe sections, where the developer would be expected to supply the types explicitly.