(0) Memory safety alone doesn't fix the downsides of lacking a formally defined semantics. You can turn most undefined behavior into trapped errors for the chea

(0) Memory safety alone doesn't fix the downsides of lacking a formally defined semantics. You can turn most undefined behavior into trapped errors for the cheap price of a constant overhead factor, but that won't make writing correct programs any little bit easier. Your programs will just fail in more manageable ways. (1) Once you have a formally defined semantics, undefined behavior is no big deal, because you have the tools to prove its absence in whatever program you're writing.