QPolygonF Heap Corruption

I am getting this error message.  It is generated by the QPolygon destructor in the free call.

    ~QArrayDataPointer()
    {
        if (!deref()) {
            (*this)->destroyAll();
            free(d);       <-----------  HERE
        }
    }

Attached is an example that crashes immediately after running.

If you comment out the line

    poly.resize(2 + 2 * notches);

in the file PhotoRotationDial.cpp, the crash will not occur.

Stack trace

>    QtImageRotater.exe!free_dbg_nolock(void * const block, const int block_use) Line 996    C++
     QtImageRotater.exe!_free_dbg(void * block, int block_use) Line 1030    C++
     QtImageRotater.exe!free(void * block) Line 39    C++
     QtImageRotater.exe!QArrayDataPointer<QPointF>::~QArrayDataPointer<QPointF>() Line 110    C++
     QtImageRotater.exe!QList<QPointF>::~QList<QPointF>()    C++
     QtImageRotater.exe!QPolygonF::~QPolygonF()    C++
     QtImageRotater.exe!drawDial(const QStyleOptionSlider * option, QPainter * p) Line 384    C++
     QtImageRotater.exe!PhotoRotationDial::paintEvent(QPaintEvent * event) Line 481    C++