Rectangle {
    id: markerRect
    width: 40
    height: 40
    color: "red"
    opacity: 0.5
    border.width: 10
    border.color: "black"
    radius: 4

    // Cross
    Rectangle {
        width: 1
        height: markerRect.height - 2*(markerRect.border.width)
        anchors.centerIn: parent
        color: "black"
    }
    Rectangle {
        width: markerRect.width - 2*(markerRect.border.width)
        height: 1
        anchors.centerIn: parent
        color: "black"
    }

    // Marker number
    Label {
        color: "white"
        anchors.left: markerRect.left
        anchors.top: markerRect.top
        anchors.leftMargin: markerRect.border.width
        anchors.topMargin: markerRect.border.width
        text: "Text"
    }
}

Error: main.qml:193:54: Could not compile binding for topMargin: Member width of QQuickPen of QQuickRectangle::border with type QQuickPen can be shadowed
                anchors.topMargin: markerRect.border.width