Comment by prosqlinjector

> That kind of reasoning only works if the language or ecosystem has some kind of compile time error or linter or comprehensive testing that will catch the error if the preconditions ever change.

Most requirements can't be verified at compile time, or even at runtime in a feasible amount of time.

If you expect functions to do things that they don't say they do, I don't know what to tell you. Conventions and specs are the best we have.