Question about qvector.h code of Qt 4

[karapas]

Hi all!
While I was looking at the code of qvector.h (the header file of QVector class - I use Qt 4.2.2) and I noticed something which I don't understand. For example, here is the implementation of the QVector:append() method:

template <typename T>
void QVector<T>::append(const T &t)
{
    const T copy(t);
    if (d->ref != 1 || d->size + 1 > d->alloc)
        realloc(d->size, QVectorData::grow(sizeof(Data), d->size + 1, sizeof(T),
                                           QTypeInfo<T>::isStatic));
    if (QTypeInfo<T>::isComplex)
        new (d->array + d->size) T(copy);
    else
        d->array[d->size] = copy;
    ++d->size;
}

template <typename T>
void QVector<T>::append(const T &t)
{
    const T copy(t);
    if (d->ref != 1 || d->size + 1 > d->alloc)
        realloc(d->size, QVectorData::grow(sizeof(Data), d->size + 1, sizeof(T),
                                           QTypeInfo<T>::isStatic));
    if (QTypeInfo<T>::isComplex)
        new (d->array + d->size) T(copy);
    else
        d->array[d->size] = copy;
    ++d->size;
}

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So my question is:
What's the use of the copy variable? Is it there for a reason or is it redundant?

Would the following code:

template <typename T>
void QVector<T>::append(const T &t)
{
   // const T copy(t);
    if (d->ref != 1 || d->size + 1 > d->alloc)
        realloc(d->size, QVectorData::grow(sizeof(Data), d->size + 1, sizeof(T),
                                           QTypeInfo<T>::isStatic));
    if (QTypeInfo<T>::isComplex)
        new (d->array + d->size) T(t);
    else
        d->array[d->size] = t;
    ++d->size;
}

template <typename T>
void QVector<T>::append(const T &t)
{
   // const T copy(t);
    if (d->ref != 1 || d->size + 1 > d->alloc)
        realloc(d->size, QVectorData::grow(sizeof(Data), d->size + 1, sizeof(T),
                                           QTypeInfo<T>::isStatic));
    if (QTypeInfo<T>::isComplex)
        new (d->array + d->size) T(t);
    else
        d->array[d->size] = t;
    ++d->size;
}

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do the same thing as the original code?

The same practice seems to be used in other functions of QVector as well like in QVector::fill():

template <typename T>
QVector<T> &QVector<T>::fill(const T &from, int asize)
{
    const T copy(from); //is it really needed???
    resize(asize < 0 ? d->size : asize);
    if (d->size) {
        T *i = d->array + d->size;
        T *b = d->array;
        while (i != b)
            *--i = copy;
    }
    return *this;
}

template <typename T>
QVector<T> &QVector<T>::fill(const T &from, int asize)
{
    const T copy(from); //is it really needed???
    resize(asize < 0 ? d->size : asize);
    if (d->size) {
        T *i = d->array + d->size;
        T *b = d->array;
        while (i != b)
            *--i = copy;
    }
    return *this;
}

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and probably in other classes too.

So, is this practice of creating a const copy (as an automatic variable) redundant or am I missing something???