[REG 6.5.2 → 6.5.3] Unable to determine callable overload

qrc:/qml/MainPage.qml:462: Error: Unable to determine callable overload.  Candidates are:
    
    
    

// Qml:
function updateScalebar() {
   var dist;
   dist = Math.round(...);
   UnitsHandler.updateMapScalebar(dist, 120); // this is line 462
}

// C++:
class UnitsHandler
{
    Q_OBJECT
    QML_ELEMENT
    QML_SINGLETON
public:
   Q_INVOKABLE void updateMapScalebar(qreal meters, int targetWidth);
}