TreeView: crash (as opposed to only runtime warning) if keyword "required" is not satisfied

import QtQuick.Window
import QtQuick.TreeView
import Qt.labs.qmlmodels

Window {
    width: 800
    height: 600
    visible: true

    Loader {
        anchors.fill: parent
        sourceComponent: TreeView {
            required property int testProperty
            delegate: DelegateChooser {
                DelegateChoice {
                    Rectangle {
                        implicitWidth: 100
                        implicitHeight: 30
                    }
                }
            }
        }
    }
}