Using attached property namespace crashes in component creation

1  __GI_raise                                   raise.c                   56   0x7ffff610ecc9 
2  __GI_abort                                   abort.c                   89   0x7ffff61120d8 
3  qt_message_fatal                             qlogging.cpp              1680 0x7ffff6a62cea 
4  QMessageLogger::fatal                        qlogging.cpp              793  0x7ffff6a5ecf0 
5  qt_assert                                    qglobal.cpp               3063 0x7ffff6a58015 
6  QQmlObjectCreator::setPropertyBinding        qqmlobjectcreator.cpp     945  0x7ffff7419a19 
7  QQmlObjectCreator::setupBindings             qqmlobjectcreator.cpp     702  0x7ffff7417f6b 
8  QQmlObjectCreator::populateInstance          qqmlobjectcreator.cpp     1329 0x7ffff741be25 
9  QQmlObjectCreator::createInstance            qqmlobjectcreator.cpp     1176 0x7ffff741b0d0 
10 QQmlObjectCreator::create                    qqmlobjectcreator.cpp     204  0x7ffff74151a2 
11 QQmlComponentPrivate::beginCreate            qqmlcomponent.cpp         877  0x7ffff73891e0 
12 QQmlComponent::beginCreate                   qqmlcomponent.cpp         826  0x7ffff7388e8b 
13 QQmlComponent::create                        qqmlcomponent.cpp         786  0x7ffff7388de7 
14 QQmlApplicationEnginePrivate::_q_finishLoad  qqmlapplicationengine.cpp 136  0x7ffff740c231 
15 QQmlApplicationEnginePrivate::startLoad      qqmlapplicationengine.cpp 115  0x7ffff740c001 
16 QQmlApplicationEngine::load                  qqmlapplicationengine.cpp 260  0x7ffff740c561 
17 QQmlApplicationEngine::QQmlApplicationEngine qqmlapplicationengine.cpp 219  0x7ffff740c3c8 
18 main                                         main.cpp                  7    0x400e98       

import QtQml 2.0
//import QtQuick.Controls 2.0 as C
import Qt.labs.controls 1.0 as C
import QtQuick.Window 2.0

Window {
   QtObject {
       C.ScrollIndicator.objectName: ""
   }
}