I have the same question. I've tried QMap<int, QVariable> and QHash. But both .insert() and operator[] do not work. They all crashed at the QHash::operator[] -> QHash::detach. Just like this.

qDebug() << value << role;
m_map[role] = new QVariant(value);

The value and role are both conrrect. But the m_map[] always crashed at function detach.