import QtQuick 2.0 MyBaseComponent { id: extended property bool success: false property int baseProperty: 666 property int boundProperty: baseProperty property alias aliasProperty: extended.baseProperty function extendedPropertiesTest(expected) { return (baseProperty == expected && boundProperty == expected && aliasProperty == expected); } Component.onCompleted: { if (basePropertiesTest('bar') && extendedPropertiesTest(666)) { baseProperty = 999; success = extendedPropertiesTest(999) && baseSuccess; } } }