QML anchor waring occurs by Qt 5 beta 1

Install the latest Qt5 beta 1 (http://labs.qt.nokia.com/2012/08/30/qt-5-beta-is-here/)
The QML anchor get warning when extracting its property by . operator.
('anchors' does not have member (M17))

Ex :
Rectangle {
anchors.fill: parent
}

The warning will disappear if we write by this style :

Rectangle {
anchors

}