typename, type members and non-type members: is it

问题:

Consider the following code:

struct S {
    struct type {};
    type type;
};

int main() {  
    typename S::type t;
    (void) t;
}

Apart for the fact that is far from being a good idea, I was experimenting after having read another question here on SO.
I found that the snippet above is compiled with no errors by GCC and it is rejected by clang 3.9 with the following error:

error: typename specifier refers to non-type member 'type' in 'S'

I suspect that clang is right in this case and GCC is wrong (actually, I'm opening an issue to the latter).
Is it the right conclusion or is that a valid use of typename?

---

Note: I'm not asking how to solve it, I know how to do that. I'm asking only if this code is valid or not.

回答1:

[temp.res]/4:

The usual qualified name lookup is used to find the qualified-id even in the presence of typename.

That is, unlike the case with elaborated-type-specifiers, the name lookup in this case does not ignore non-type names.

[temp.res]/3:

If the qualified-id in a typename-specifier does not denote a type or a class template, the program is ill-formed.

So the program in question is ill-formed.

[temp.res]/4 also has an example for this:

struct A {
  struct X { };
  int X;
};
struct B {
  struct X { };
};
template<class T> void f(T t) {
  typename T::X x;
}
void foo() {
  A a;
  B b;
  f(b);             // OK: T::X refers to B::X
  f(a);             // error: T::X refers to the data member A::X not the struct A::X
}