QQuickItem *QQuickLayoutAttached::item() const
{
    Q_ASSERT(qobject_cast<QQuickItem*>(parent()));
    return static_cast<QQuickItem*>(parent());
}

>	Qt5Cored.dll!qt_message_fatal(QtMsgType __formal, const QMessageLogContext & context, const QString & message) Line 937	C++
 	Qt5Cored.dll!QMessageLogger::fatal(const char * msg, ...) Line 360	C++
 	Qt5Cored.dll!qt_assert(const char * assertion, const char * file, int line) Line 1992	C++
 	qquicklayoutsplugind.dll!QQuickLayoutAttached::item() Line 350	C++
 	qquicklayoutsplugind.dll!QQuickLayoutAttached::parentLayout() Line 342	C++
 	qquicklayoutsplugind.dll!QQuickLayoutAttached::invalidateItem() Line 335	C++
 	qquicklayoutsplugind.dll!QQuickLayoutAttached::setMaximumHeight(double height) Line 220	C++
 	qquicklayoutsplugind.dll!QQuickGridLayoutBase::propagateLayoutSizeHints() Line 269	C++
 	qquicklayoutsplugind.dll!QQuickGridLayoutBase::rearrange(const QSizeF & size) Line 376	C++
 	qquicklayoutsplugind.dll!QQuickGridLayoutBase::geometryChanged(const QRectF & newGeometry, const QRectF & oldGeometry) Line 305	C++
 	Qt5Quickd.dll!QQuickItem::setImplicitHeight(double h) Line 5948	C++
 	qquicklayoutsplugind.dll!QQuickGridLayoutBase::propagateLayoutSizeHints() Line 267	C++
 	qquicklayoutsplugind.dll!QQuickGridLayoutBase::rearrange(const QSizeF & size) Line 376	C++
 	qquicklayoutsplugind.dll!QQuickLayout::event(QEvent * e) Line 379	C++

import QtQuick 2.0
import QtQuick.Controls 1.0
import QtQuick.Layouts 1.0

Item {
    id: root
    width: 1024
    height: 768
    states: [
        State {
            name: "state02"
            ParentChange { target: redRect; parent: root; x: 10; y: 10 }
        }
    ]

    ColumnLayout {
        
        Rectangle {
            id: rext2
            height: 200
            width: 200
            color: "blue"
            MouseArea {
                anchors.fill: parent
                onClicked: {
                    root.state = "state02"
                }
            }
        }

        Rectangle {
            id: redRect
            height: 200
            width: 200
            color: "red"
        }
        
    }


}