> Why don't we just design our software in such a way that the interfaces between components are simple so that we can easily remember which functions accept wh

> Why don't we just design our software in such a way that the interfaces between components are simple so that we can easily remember which functions accept what kinds of input Good luck in defining 'simple'. For me, a simple function only accepts inputs which it knows how to handle, and performs no side effects. Bonus points if it always terminates. Personally I cannot maintain this level of simplicity without a type checker. But on the plus side, you're still allowed to remember what your functions accept! The checker only kicks in if you get it wrong.