Language vision regarding safety guarantees

tczajka: > By that criterion, all the functions that I provide in APIs provided by my crates would have full guarantees because I'm a careful programmer. Exactly. And that's what expected of you today. But Rust is a language supposed to let people write logic bugs without them turning into UB. And it partially fails to do that. It only does at top-level of the dependency tree (e.g. if you write a safe program).