How to use singleton in another singleton

[nekobako]

Hello,

I'm using Qt 5.3.2 and I tried to use singleton object in another singleton object in the same directory.
But the program exited with code -1.

It is a situation such as the following. (this is just an example)

Directory structure
@root [directory]
|-Test.qml (Window)
|-singletons [directory]
|-qmldir
|-Colors.qml (Singleton)
|-Red.qml (Singleton)
|-Green.qml (Singleton)@

---

qmldir
@singleton Colors Colors.qml
singleton Red Red.qml
singleton Green Green.qml@

---

Colors.qml
@pragma Singleton
import QtQuick 2.0

QtObject {
readonly property color colorR: "#FF0000"
readonly property color colorG: "#00FF00"
readonly property color colorB: "#0000FF"
}@

---

Red.qml
@pragma Singleton
import QtQuick 2.0
import '.'

QtObject {
readonly property color color1: Colors.colorR
}@

---

Green.qml
@pragma Singleton
import QtQuick 2.0
import '.'

QtObject {
readonly property color color1: Colors.colorG
}@

---

Test.qml:
@import QtQuick 2.3
import QtQuick.Controls 1.2
import 'singletons'

ApplicationWindow {
width: 640
height: 480

Rectangle {
    anchors.centerIn: parent
    width: 100
    height: 100
    color: Red.color1
}

}
@

---

Red.qml and Green.qml are using Colors.qml by importing '.'.
I think this part is something wrong.

The program works fine if I remove
@import '.'@

from Green.qml.
But I will not be able to use Green.color1 in Test.qml.

Please can anyone help me with this issue?

Thanks.