Cannot use a Repeater for Item3D elements in Qt 5

import QtQuick 2.0
import Qt3D 2.0
import Qt3D.Shapes 2.0

Viewport {
    width: 1024; height: 768
    id: viewport

    camera: Camera { eye: Qt.vector3d(-5, 5, 5) }

    Repeater {
        model: 3
        Teapot { x: index; scale: 0.5; effect: Effect { color: "green"} }
    }

    // Repeater should generate these items:
    // Teapot { x: 0; scale: 0.5; effect: Effect { color: "green"} }
    // Teapot { x: 1; scale: 0.5; effect: Effect { color: "green"} }
    // Teapot { x: 2; scale: 0.5; effect: Effect { color: "green"} }
}