If your type system is powerful enough (like in Rust), then you can use it to express relations in your problem domain and have compiler enforce them for you before the code even runs.
I think you missed the "unless" in my question. I am well aware that having chosen to treat types as a first class problem, a coder can leverage that intent. My point is simply that there is a populous, productive world of software development in which typing is a humdrum issue for the coders. C.f. the last 30 years of Javascript and Python