Error assign QUuid to QVariant

#include <QUuid>
#include <QVariant>

int main()

{ QUuid u1 = QUuid(); QVariant v1 = u1; //assign failed, v1 has invalid value QUuid u2 = QUuid::createUuid(); QVariant v2(u2);//assign failed, v2 has invalid value return 0; }