#include <iostream>
#include <map>

struct HeavyObject
{
    HeavyObject() = default;

    HeavyObject(HeavyObject const&)
    {
        std::cout << "Copy-Ctor!";
    }
};

int main()
{
    std::map<int, HeavyObject> map;
    map.insert( std::make_pair(7, HeavyObject()) );
}