Using QMultiMapIterator to iterate over a QMultiMap asserts

#include <QtCore>

int main(int argc, char *argv[])
{
    QMultiMap<int, int> mm;

    mm.insert(0, 0);
    mm.insert(1, 10);
    mm.insert(2, 100);
    mm.insert(2, 200);
    mm.insert(3, 1000);
    mm.insert(3, 2000);
    mm.insert(3, 3000);

    QMultiMapIterator it(mm);
    while (it.hasNext()) {
        qDebug() << it.key() << it.value();
        it.next();
    }

    return 0;
}

ASSERT: "item_exists()" in file /Users/vohi/qt/dev/qtbase-build/include/QtCore/../../../qtbase/src/corelib/tools/qmap.h, line 1410
Abort trap: 6