Crash in QML after upgrade to Qt 5.6

#0  0x00007ffff0cabe90 in __memcpy_sse2_unaligned () from /usr/lib/libc.so.6
#1  0x00007ffff4ccfd2f in QV4::Heap::String::append (data=data@entry=0x7fff33e45c20, ch=0x3249fd8) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4string.cpp:234
#2  0x00007ffff4ccfd75 in QV4::Heap::String::simplifyString (this=this@entry=0x7fff33e45c20) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4string.cpp:187
#3  0x00007ffff4c8b520 in QV4::Heap::String::toQString (this=0x7fff33e45c20) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4string_p.h:82
#4  QV4::Heap::StringObject::length (this=this@entry=0x7fff3315ff30) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4stringobject.cpp:101
#5  0x00007ffff4c8b589 in QV4::Heap::StringObject::StringObject (this=0x7fff3315ff30, engine=0xee7e70, str=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4stringobject.cpp:88
#6  0x00007ffff4c3db33 in QV4::MemoryManager::alloc<QV4::StringObject, QV4::ExecutionEngine*, QV4::String const*> (arg2=0x7fffd005a4e8, arg1=0xee7e70, this=<optimized out>)
    at ../../include/QtQml/5.6.0/QtQml/private/../../../../../../../frameworks/qt5/qtdeclarative/src/qml/memory/qv4mm_p.h:126
#7  QV4::ExecutionEngine::newStringObject (this=0xee7e70, string=0x7fffd005a4e8) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4engine.cpp:559
#8  0x00007ffff4cc9c61 in QV4::RuntimeHelpers::convertToObject (engine=engine@entry=0xee7e70, value=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4runtime.cpp:443
#9  0x00007ffff4cd142b in QV4::Value::toObject (this=<optimized out>, e=e@entry=0xee7e70) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4value.cpp:304
#10 0x00007ffff4cce376 in QV4::Runtime::typeofMember (engine=engine@entry=0xee7e70, base=..., nameIndex=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4runtime.cpp:1160
#11 0x00007ffff4cbcd44 in QV4::Moth::VME::run (this=this@entry=0x7fffffffa547, engine=engine@entry=0xee7e70, code=<optimized out>, code@entry=0x7fffc4932a08 "\300\307\313\364\377\177", storeJumpTable=storeJumpTable@entry=0x0)
    at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4vme_moth.cpp:688
#12 0x00007ffff4cbe4da in QV4::Moth::VME::exec (engine=0xee7e70, code=0x7fffc4932a08 "\300\307\313\364\377\177") at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4vme_moth.cpp:960
#13 0x00007ffff4c7002a in QV4::SimpleScriptFunction::call (that=<optimized out>, callData=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4functionobject.cpp:569
#14 0x00007ffff4ccd3a1 in QV4::Object::call (d=0x7fffd005a470, this=0x7fffd005a4c8) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4object_p.h:301
#15 QV4::Runtime::callActivationProperty (engine=engine@entry=0xee7e70, nameIndex=<optimized out>, callData=0x7fffd005a470) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4runtime.cpp:953
#16 0x00007ffff4cbca4f in QV4::Moth::VME::run (this=this@entry=0x7fffffffa797, engine=engine@entry=0xee7e70, code=<optimized out>, code@entry=0x7fffc49d1588 "\300\307\313\364\377\177", storeJumpTable=storeJumpTable@entry=0x0)
    at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4vme_moth.cpp:626
#17 0x00007ffff4cbe4da in QV4::Moth::VME::exec (engine=0xee7e70, code=0x7fffc49d1588 "\300\307\313\364\377\177") at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4vme_moth.cpp:960
#18 0x00007ffff4c7002a in QV4::SimpleScriptFunction::call (that=<optimized out>, callData=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4functionobject.cpp:569
#19 0x00007ffff4d5a13a in QV4::Object::call (d=0x7fffd005a3e8, this=0x7fff33028cb0) at ../../include/QtQml/5.6.0/QtQml/private/../../../../../../../frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4object_p.h:301
#20 QQmlJavaScriptExpression::evaluate (this=this@entry=0x2a1d050, callData=callData@entry=0x7fffd005a3e8, isUndefined=isUndefined@entry=0x7fffffffa9d8) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmljavascriptexpression.cpp:189
#21 0x00007ffff4d5a5f1 in QQmlJavaScriptExpression::evaluate (this=this@entry=0x2a1d050, isUndefined=isUndefined@entry=0x7fffffffa9d8) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmljavascriptexpression.cpp:149
#22 0x00007ffff4d6166e in QQmlBinding::update (this=0x2a1d050, flags=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlbinding.cpp:187
#23 0x00007ffff4d6a148 in QQmlObjectCreator::finalize (this=0x2a09df0, interrupt=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlobjectcreator.cpp:1174
#24 0x00007ffff4cf82ea in QQmlIncubatorPrivate::incubate (this=this@entry=0x2f262a0, i=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlincubator.cpp:348
#25 0x00007ffff4cf8c67 in QQmlEnginePrivate::incubate (this=this@entry=0xef0d00, i=..., forContext=forContext@entry=0x326f6b0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlincubator.cpp:87
#26 0x00007ffff4cf472c in QQmlComponent::create (this=<optimized out>, incubator=..., context=<optimized out>, forContext=forContext@entry=0x0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlcomponent.cpp:1053
#27 0x00007ffff587daba in QQuickLoaderPrivate::_q_sourceLoaded (this=this@entry=0x2efd460) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/items/qquickloader.cpp:713
#28 0x00007ffff587dbd8 in QQuickLoaderPrivate::load (this=0x2efd460) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/items/qquickloader.cpp:596
#29 0x00007ffff587e36d in QQuickLoader::qt_static_metacall (_o=_o@entry=0x2fddda0, _c=_c@entry=QMetaObject::WriteProperty, _id=_id@entry=1, _a=_a@entry=0x7fffffffae80) at .moc/moc_qquickloader_p.cpp:249
#30 0x00007ffff587e66b in QQuickLoader::qt_metacall (this=0x2fddda0, _c=QMetaObject::WriteProperty, _id=1, _a=0x7fffffffae80) at .moc/moc_qquickloader_p.cpp:301
#31 0x00007ffff4cf1ad1 in QQmlPropertyPrivate::write (object=object@entry=0x2fddda0, property=..., value=..., context=0x2c03cf0, flags=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlproperty.cpp:1234
#32 0x00007ffff4cb9aaf in QV4::QObjectWrapper::setProperty (engine=0xee7e70, object=0x2fddda0, property=0x7fffc4055bd0, value=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4qobjectwrapper.cpp:551
#33 0x00007ffff4ccf7fe in QV4::Runtime::setQmlQObjectProperty (engine=engine@entry=0xee7e70, object=..., propertyIndex=<optimized out>, value=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4runtime.cpp:1448
#34 0x00007ffff4cbc594 in QV4::Moth::VME::run (this=this@entry=0x7fffffffb0e7, engine=engine@entry=0xee7e70, code=<optimized out>, code@entry=0x7fffc40bbe78 "\300\307\313\364\377\177", storeJumpTable=storeJumpTable@entry=0x0)
    at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4vme_moth.cpp:508
#35 0x00007ffff4cbe4da in QV4::Moth::VME::exec (engine=0xee7e70, code=0x7fffc40bbe78 "\300\307\313\364\377\177") at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4vme_moth.cpp:960
#36 0x00007ffff4c7002a in QV4::SimpleScriptFunction::call (that=<optimized out>, callData=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4functionobject.cpp:569
#37 0x00007ffff4d5a13a in QV4::Object::call (d=0x7fffd005a300, this=0x7fff32913780) at ../../include/QtQml/5.6.0/QtQml/private/../../../../../../../frameworks/qt5/qtdeclarative/src/qml/jsruntime/qv4object_p.h:301
#38 QQmlJavaScriptExpression::evaluate (this=this@entry=0x37226a0, callData=callData@entry=0x7fffd005a300, isUndefined=isUndefined@entry=0x0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmljavascriptexpression.cpp:189
#39 0x00007ffff4cfe771 in QQmlBoundSignalExpression::evaluate (this=<optimized out>, a=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlboundsignal.cpp:237
#40 0x00007ffff4cfec23 in QQmlBoundSignal_callback (e=0x2c49360, a=0x0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlboundsignal.cpp:332
#41 0x00007ffff4d38bce in QQmlNotifier::emitNotify (endpoint=<optimized out>, a=a@entry=0x0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlnotifier.cpp:94
#42 0x00007ffff4ce2664 in QQmlData::signalEmitted (object=0x3070f70, index=3, a=0x0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlengine.cpp:772
#43 0x00007ffff1b05111 in QMetaObject::activate (sender=sender@entry=0x3070f70, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qobject.cpp:3609
#44 0x00007ffff1b05ff7 in QMetaObject::activate (sender=sender@entry=0x3070f70, m=m@entry=0x7ffff4e96f20 <QQmlComponentAttached::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0)
    at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qobject.cpp:3588
#45 0x00007ffff4db9e40 in QQmlComponentAttached::completed (this=this@entry=0x3070f70) at .moc/moc_qqmlcomponentattached_p.cpp:135
#46 0x00007ffff4d6aa88 in QQmlObjectCreator::finalize (this=0x3303210, interrupt=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlobjectcreator.cpp:1215
#47 0x00007ffff4cf82ea in QQmlIncubatorPrivate::incubate (this=this@entry=0x2a1cba0, i=...) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlincubator.cpp:348
#48 0x00007ffff4cf8c67 in QQmlEnginePrivate::incubate (this=0xef0d00, this@entry=0x8000000000000000, i=..., forContext=forContext@entry=0x36811f0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/qml/qqmlincubator.cpp:87
#49 0x00007ffff4d90863 in QQmlDelegateModelItem::incubateObject (this=this@entry=0x35499f0, component=<optimized out>, engine=<optimized out>, context=context@entry=0x2a16d00, forContext=forContext@entry=0x36811f0)
    at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/types/qqmldelegatemodel.cpp:1958
#50 0x00007ffff4d9a567 in QQmlDelegateModelPrivate::object (this=this@entry=0x3697160, group=QQmlListCompositor::Default, index=index@entry=2, asynchronous=asynchronous@entry=false) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/types/qqmldelegatemodel.cpp:981
#51 0x00007ffff4d9a825 in QQmlDelegateModel::object (this=<optimized out>, index=2, asynchronous=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/qml/types/qqmldelegatemodel.cpp:1017
#52 0x00007ffff58aaa6f in QQuickItemViewPrivate::createItem (this=this@entry=0x367eff0, modelIndex=modelIndex@entry=2, asynchronous=asynchronous@entry=false) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/items/qquickitemview.cpp:2303
#53 0x00007ffff58660a5 in QQuickGridViewPrivate::applyInsertionChange (this=0x367eff0, change=..., insertResult=<optimized out>, addedItems=<optimized out>, movingIntoView=<optimized out>)
    at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/items/qquickgridview.cpp:2425
#54 0x00007ffff58aba8b in QQuickItemViewPrivate::applyModelChanges (this=this@entry=0x367eff0, totalInsertionResult=totalInsertionResult@entry=0x7fffffffd4f0, totalRemovalResult=totalRemovalResult@entry=0x7fffffffd520)
    at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/items/qquickitemview.cpp:2020
#55 0x00007ffff58ac332 in QQuickItemViewPrivate::layout (this=0x367eff0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/items/qquickitemview.cpp:1868
#56 0x00007ffff57de8cf in QQuickWindowPrivate::polishItems (this=this@entry=0x2528560) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/items/qquickwindow.cpp:263
#57 0x00007ffff57ae0cb in QSGGuiThreadRenderLoop::renderWindow (this=this@entry=0xa936c0, window=0x1111db0) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/scenegraph/qsgrenderloop.cpp:379
---Type <return> to continue, or q <return> to quit---
#58 0x00007ffff57af261 in QSGGuiThreadRenderLoop::event (this=0xa936c0, e=<optimized out>) at /home/kde-devel/frameworks/qt5/qtdeclarative/src/quick/scenegraph/qsgrenderloop.cpp:490
#59 0x00007ffff2709b7c in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0xa936c0, e=0x7fffffffd920) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3717
#60 0x00007ffff270eb46 in QApplication::notify (this=0x7fffffffdc80, receiver=0xa936c0, e=0x7fffffffd920) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3498
#61 0x00007ffff1ad7d78 in QCoreApplication::notifyInternal2 (receiver=0xa936c0, event=event@entry=0x7fffffffd920) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1002
#62 0x00007ffff1b2e6ae in QCoreApplication::sendEvent (event=0x7fffffffd920, receiver=<optimized out>) at ../../include/QtCore/../../../../frameworks/qt5/qtbase/src/corelib/kernel/qcoreapplication.h:227
#63 QTimerInfoList::activateTimers (this=0x75ad40) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qtimerinfo_unix.cpp:637
#64 0x00007ffff1b2ebc1 in timerSourceDispatch (source=<optimized out>) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:176
#65 0x00007fffe9f529fd in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#66 0x00007fffe9f52ce0 in ?? () from /usr/lib/libglib-2.0.so.0
#67 0x00007fffe9f52d8c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#68 0x00007ffff1b2f7ff in QEventDispatcherGlib::processEvents (this=0x76a050, flags=...) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qeventdispatcher_glib.cpp:417
#69 0x00007ffff1ad580a in QEventLoop::exec (this=this@entry=0x7fffffffdb50, flags=..., flags@entry=...) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qeventloop.cpp:204
#70 0x00007ffff1ade7cd in QCoreApplication::exec () at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1272
#71 0x0000000000470c5d in main (argc=1, argv=0x7fffffffe298) at /home/kde-devel/frameworks/plasma-workspace/shell/main.cpp:176