Yes? What do you think fuzzing, unit testing, integration testing is for? It's an empirical evaluation of correctness. Literally just try and see.

For actual correctness verification in the strong sense, you'd need to start from a specification written in a formal language so that it's machine checkable, which if I had to guess not even win.rar GmbH has.

This is Rust we're talking about. It doesn't even need to work; as long as it compiles, it's correct.