LinearGradient example issues warning

import QtQuick 2.0
import QtGraphicalEffects 1.0

Item {
    width: 300
    height: 300

    LinearGradient {
        anchors.fill: parent
        start: Qt.point(0, 0)
        end: Qt.point(0, 300)
        gradient: Gradient {
            GradientStop { position: 0.0; color: "white" }
            GradientStop { position: 1.0; color: "black" }
        }
    }
}

qml/QtGraphicalEffects/LinearGradient.qml:254:16: Unable to assign [undefined] to QQuickItem*