C++ rvalue assignment what caused this program to crash but lvalue assignment not

Question

I am studying C++ rvalue reference by example. It was like this:

Intvec::~Intvec()
{
    log("destructor");
    if (m_data) {
        delete[] m_data;
        m_data = 0;
    }
}

Intvec::Intvec(const Intvec& other)
    :m_size(other.m_size), m_data(new int[m_size])
{
    log("copy constructor");
    for(size_t i = 0; i<m_size; ++i)
        m_data[i] = other.m_data[i];
}

Intvec& Intvec::operator=(const Intvec& other)
{
    log("copy assignment operator");
    Intvec tmp(other);
    std::swap(m_size, tmp.m_size);
    std::swap(m_data, tmp.m_data);
    return *this;
}

Then I changed it to be following. When debugging step by step, it calls delete[] many times until it crashes: read access violation at: 0x3f7a2f91

Intvec& Intvec::operator=(const Intvec& other)
{
    log("copy assignment operator");
    size_t othersize = other.m_size;
    int* otherdata = other.m_data;
    std::swap(m_size, othersize);
    std::swap(m_data, otherdata);
    return *this;
}

I am confused at:

1. In example, Intvec tmp(other) returns a tmporary tmp object, it would be destroyed after return *this, it does not crash.
2. In my code, other is an rvalue, it is also destroyed after return *this, why it crashes because of read access at wrong memory.

It only happens to rvalue, not lvalue.

    Intvec v1 = Intvec(10);
    Intvec v2;
    cout << "assigning lvalue...\n";
    v2 = v1;
    cout << "ended assigning lvalue...\n";

    Intvec v2;
    cout << "assigning rvalue...\n";
    v2 = Intvec(33);
    cout << "ended assigning rvalue...\n";

Answer 1

For your operator=, after v2 = Intvec(33);, the data member m_data of both v2 and the temporary Intvec point to the same array allocated. Then with the destroy of the temporary and v2, m_data would be deleted twice, which leads to UB.