Yeah I don't understand the argument. If you can't convince the compiler that that branch will never be taken, then I strongly suspect that it may be taken.
That's not the point. The point is that if it is never taken, you can't test it. They don't care that it inserts a conditional OP to check, they care that they can't test the conditional path.
But, there is no conditional path when the type system can assure the compiler that there is nothing to be conditional about. Do they mean that it's impossible to be 100% sure about if there's a conditional path or not?
