But now the conversation's going in a circle. In a decent static language, you should never have to run into that particular problem. Assuming it's a modern st

But now the conversation's going in a circle. In a decent static language, you should never have to run into that particular problem. Assuming it's a modern static OO language, your business logic should depend on a User interface, so that it never has to take a dependency on implementation details like that. Even if User was a class beforehand, you can easily extract an interface at a later date, when you find that you need to avoid some tight coupling. Don't blame the gun for what happens when you point it toward your foot and pull the trigger.