move_namespace.cpp

#include <iostream>
#include <vector>

namespace A
{
class Array
{
public:
    Array() = default;
    void test() { }
    Array(Array && array) { a = std::move(array.a); }
    Array & operator=(Array && array)
    {
        a = std::move(array.a);
        return *this;
    }

    std::vector<int> a;
};
class C
{
public:
    C() = default;
    void setArray(Array * arr_) { arr = std::move(*arr_); }
    Array arr;
};
}

namespace B
{
class Array
{
public:
    Array() = default;
    Array(Array && array) { a = std::move(array.a); }
    Array & operator=(Array && array)
    {
        a = std::move(array.a);
        return *this;
    }

    std::vector<int> a;
};
class C
{
public:
    C() = default;
    void setArray(Array * arr_) { arr = std::move(*arr_); }
    Array arr;
};
}

int main()
{
    A::Array arr;
    arr.a.push_back(10);
    auto b = std::move(arr);
    std::cout << arr.a.size() << std::endl;
    std::cout << b.a.size() << std::endl;

    A::C c1;
    c1.arr.a.push_back(10);
    c1.arr.a.push_back(10);
    c1.arr.a.push_back(10);
    B::C c2;
    c2.setArray((B::Array *)(&c1.arr));
    std::cout << c1.arr.a.size() << std::endl;
    std::cout << c2.arr.a.size() << std::endl;
}