Re: non virtual interfaces

[Alexandr Druzhinin]

if I use protected instead of private in interface like:
interface Transmogrifier
{
        final void thereAndBack()
        {
                transmogrify();
                untransmogrify();
        }
        protected:
                void transmogrify();
                void untransmogrify();
}

class CardboardBox: Transmogrifier
{
        override protected void transmogrify() { }
        override void untransmogrify() {}
}

int main()
{
        auto cb = new CardboardBox();
        return 0;
}

it compiles, but why does compiler permit making untransmogrify() be 
public? How can I prohibit this? May be it just unrealized yet?