that's because assigning -1 to an unsigned number is an idiomatic, safe and portable way to setting all bits to 1. You could argue that an explicit cast should

that's because assigning -1 to an unsigned number is an idiomatic, safe and portable way to setting all bits to 1. You could argue that an explicit cast should be warranted in this case, and I sort of agree, but it would break way too much code.