template<typename T> class n;

template<typename T> class b {
protected:
	typedef n<T> n_t;
};

template<typename T> class d : private b<T> {
	using typename b<T>::n_t;
public:
	n_t*test0();
	typename n_t*test1();
	typename b<T>::n_t*test2();
};

void test() {
	d<int> di;
	di.test0();
	di.test1();
	di.test2();
}

results in errors on the unqualified uses of n_t in class d. I cannot see
anything invalid with these constructs, nor can Intel's or a couple of other
compilers I tried this with.