> As I said, you can't "properly" check it at the point you are checking. > Which is why I complain - you're not checking this properly!
This is understood. There is a choice to be made, between an early check (which will benefit our casual users) catching this particular special case, and a later check. I argued for an earlier check, because it was a particular annoying and particularly un-user-friendly error, and wrote the check in a way to minimize the number of false negatives. But, as you say, it is not possible to write a perfect check at that early point. FX
