Thank you for the example. > And sure, you could invent a rule to "fix" this case, too. I would just do the simple thing. If X is not already defined when it

Thank you for the example. > And sure, you could invent a rule to "fix" this case, too. I would just do the simple thing. If X is not already defined when it is used in the function signature I would just give a compile time error. Easy to implement for the compiler author, easy for the developer to understand and rectify. > But next week, you'll encounter another headache, and another. I believe you. I guess it is one of those things one has to see for themselves to really appreciate.