gistfile1.cpp

#include <iostream>

template <typename T>
struct nesting
{
    struct nested
    {
        T value;
    };

    template <typename U>
    friend T get_value(U const& x)
    {
        return x.value;
    }
};

int main()
{
    nesting<int>::nested v = { 42 };
    std::cout << get_value(v) << std::endl;
}