decltype fails on struct member declared in template class

I am having an issue with code failing to compile for an external library I am using. I believe that library compiles fine with gcc, but it fails to compile for me with clang.

I can recreate the issue as follows

template <class T>
class A {
public:
    struct B {
        int a;
    };

    void test();

private:
    T _t;
};

template <class T>
void A<T>::test()
{
    printf("Result %d", std::numeric_limits<decltype(B::a)>::max());
}

int main(int argc, char** argv)
{
    auto t = A<int>();
    t.test();
    return 0;
}

This fails to compile on clang with the following error

error: invalid use of non-static data member 'a' printf("Result %d", std::numeric_limits<decltype(B::a)>::max());

My questions are as follows:

-What is the expected behavior?

-decltype on non-static members was added in c++11. Does this apply to those declared in template classes?

-Is this a compiler bug? Or an example of non-conformant code working with gcc?