typedef and using in c++11

#include <iostream>

struct cls {
    using type = double;          //case 1
    // typedef double type;         //case 2
};

template<typename T>
void foo(typename T::type) {
    std::cout<<"T::type\n";
}

int main() {
    foo<cls>(22.2);
}

I believe using and be used instead of typedef. In the above code I'm getting error for case 1 but not for case 2.

error: expected nested-name-specifier before 'type'

Could someone please explain why??