Error when accessing StackView attached properties via popped item

import QtQuick 2.6
import QtQuick.Window 2.2
import Qt.labs.controls 1.0

Window {
    visible: true

    StackView {
        anchors.fill: parent
        initialItem: page1Component

        Component {
            id: page1Component

            Rectangle {
                id: root

                Text {
                    text: "Page 1"
                    font.pixelSize: 40
                    anchors.centerIn: parent
                }

                Button {
                    text: "Push"
                    onClicked: root.StackView.view.push(page2Component)
                }
            }
        }

        Component {
            id: page2Component

            Rectangle {
                id: root

                Text {
                    text: "Page 2"
                    font.pixelSize: 40
                    anchors.centerIn: parent
                }

                property bool someBinding: root.StackView.view.currentItem === root

                Button {
                    text: "Pop"
                    onClicked: root.StackView.view.pop()
                }
            }
        }
    }
}