#include <memory>
#include <vector>

struct A {
    A(std::unique_ptr<int> a) : a(std::move(a)) {}

    bool gone() {
        return a == nullptr;
    }
    std::unique_ptr<int> a;
};

std::vector<A> vec;

void foo(A&& a, bool queue) {
    if (queue) {
        vec.push_back(std::move(a));
    }
}

int main()
{
    A a(std::make_unique<int>(1337));

    foo(std::move(a), false);
    std::printf("Lost ownership: %un", a.gone());
    if (a.a != nullptr) {
        std::printf("A.a: %dn", *a.a);
    }


    foo(std::move(a), true);
    std::printf("Lost ownership: %un", a.gone());
    if (a.a != nullptr) {
        std::printf("A.a: %dn", *a.a);
    }

}