How to hide Boost intrusive list hook ?

Question

In the following code:

using namespace boost::intrusive;

struct Data {
    int i;
private:
    list_member_hook<> list_node;     // How to make this work?
};


using List = list<
    Data,
    member_hook< Data, list_member_hook<>,
    &Data::list_node>      // compiler error here.
>;

How can I make list_node private?