template <typename L, typename R, typename = std::void_t<>>
struct is_equal_comparable : std::false_type {};

template <typename L, typename R>
struct is_equal_comparable<L, R, std::void_t<decltype(std::declval() == std::declval())>> : std::true_type {};

template <typename L, typename R>
constexpr bool is_equal_comparable_v = is_equal_comparable<L, R>::value;

int main()
{
   
struct comparable {


bool operator==(const comparable&) const { return true; }


bool operator==(int) const { return true; }

};


static_assert (is_equal_comparable_v<comparable, comparable>);

static_assert (is_equal_comparable_v<comparable, int>);

static_assert (is_equal_comparable_v<int, comparable>);
   return 0;
}

struct node_t
{
   std::map
       <
           int,
           std::unique_ptr
       >   nodes;
};

int main()
{
   node_t node;
   node.nodes[1] = std::unique_ptr( new int( 1337 ) );
   
   std::vector<node_t> v;
   v.emplace_back( std::move( node ) );

   std::cout << *v[0].nodes[1].get();
   return 0;
}