Oh for sure, use better types to express the problem in ways that the compiler can catch mistakes. But... you do need to show at some point that your code actually does what you claim it does, even if just for a single use case; might as well piggyback sanitizers since you're running tests anyways.

Re: Dijkstra, I'm not trying to prove that the code has no memory errors, I'm trying to make sure none get triggered in production ie. the difference between computer science and software engineering. If there was a simple and easy way to do behaviour proofs I'd be happy to use that, but coq et al. are a real pain.