QtCreator crashes with bad_alloc in FakeVimHandler

After some time working on a big project in vim mode (non-english keyboard), QtCreator crashes with a bad_alloc:

Output of QtCreator before the crash:
QTextCursor::setPosition: Position '253192576' out of range
QTextCursor::setPosition: Position '795173737' out of range
QTextCursor::setPosition: Position '1919052108' out of range
terminate called after throwing an instance of 'std::bad_alloc'
what(): std::bad_alloc
/bin/sh: line 1: 6288 Aborted

Seems that insertState.backspaces and insertState.deletes get way to high values.
Here is the backtrace:

(gdb) backtrace
#0 0x00007f3a8d0187ad in nanosleep () from /lib64/libc.so.6
#1 0x00007f3a8d018644 in sleep () from /lib64/libc.so.6
#2 0x00007f3a50120dd2 in KCrash::startProcess(int, char const**, bool) () from /lib64/libKF5Crash.so.5
#3 0x00007f3a50121280 in KCrash::defaultCrashHandler(int) () from /lib64/libKF5Crash.so.5
#4 <signal handler called>
#5 0x00007f3a8cf84a98 in raise () from /lib64/libc.so.6
#6 0x00007f3a8cf8669a in abort () from /lib64/libc.so.6
#7 0x00007f3a8d8b9add in _gnu_cxx::_verbose_terminate_handler() () from /lib64/libstdc++.so.6
#8 0x00007f3a8d8b7936 in ?? () from /lib64/libstdc++.so.6
#9 0x00007f3a8d8b7981 in std::terminate() () from /lib64/libstdc++.so.6
#10 0x00007f3a8d8b7b99 in __cxa_throw () from /lib64/libstdc++.so.6
#11 0x00007f3a8e1932e2 in qBadAlloc() () from /lib64/libQt5Core.so.5
#12 0x00007f3a8e23c58d in QString::reallocData(unsigned int, bool) () from /lib64/libQt5Core.so.5
#13 0x00007f3a8e23c5f8 in QString::resize(int) () from /lib64/libQt5Core.so.5
#14 0x00007f3a8e23c66d in QString::expand(int) () from /lib64/libQt5Core.so.5
#15 0x00007f3a8e23cc09 in QString::insert(int, QChar const*, int) () from /lib64/libQt5Core.so.5
#16 0x00007f3a610712c3 in QString::insert (s=..., i=0, this=0xca45450) at /usr/include/qt5/QtCore/qstring.h:424
#17 QString::prepend (s=..., this=0xca45450) at /usr/include/qt5/QtCore/qstring.h:434
#18 FakeVim::Internal::FakeVimHandler::Private::commitInsertState (this=this@entry=0xca44dc0)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:2587
#19 0x00007f3a61080e6e in FakeVim::Internal::FakeVimHandler::Private::handleInsertOrReplaceMode (this=this@entry=0xca44dc0, input=...)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:4726
#20 0x00007f3a6107ea5b in FakeVim::Internal::FakeVimHandler::Private::handleDefaultKey (this=this@entry=0xca44dc0, input=...)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:2773
#21 0x00007f3a6107eb3f in FakeVim::Internal::FakeVimHandler::Private::handleCurrentMapAsDefault (this=this@entry=0xca44dc0)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:2793
#22 0x00007f3a6107ef68 in FakeVim::Internal::FakeVimHandler::Private::handleKey (this=this@entry=0xca44dc0, input=...)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:2709
#23 0x00007f3a6107f0da in FakeVim::Internal::FakeVimHandler::Private::handleEvent (this=0xca44dc0, ev=ev@entry=0x7ffcc624cf60)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:2529
#24 0x00007f3a6107f270 in FakeVim::Internal::FakeVimHandler::eventFilter (this=0xca446d0, ob=0xeee3c10, ev=0x7ffcc624cf60)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:8577
#25 0x00007f3a8e3836d2 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /lib64/libQt5Core.so.5
#26 0x00007f3a8ecb7be5 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#27 0x00007f3a8ecbe816 in QApplication::notify(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#28 0x00007f3a8e383968 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib64/libQt5Core.so.5
#29 0x00007f3a8ed183e3 in QWidgetWindow::event(QEvent*) () from /lib64/libQt5Widgets.so.5
#30 0x00007f3a8ecb7c0c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#31 0x00007f3a8ecbce96 in QApplication::notify(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#32 0x00007f3a8e383968 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib64/libQt5Core.so.5
#33 0x00007f3a8e6ce328 in QGuiApplicationPrivate::processKeyEvent(QWindowSystemInterfacePrivate::KeyEvent*) () from /lib64/libQt5Gui.so.5
#34 0x00007f3a8e6d34c5 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /lib64/libQt5Gui.so.5
#35 0x00007f3a8e6b06eb in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Gui.so.5
#36 0x00007f3a7cdc1940 in userEventSourceDispatch(_GSource*, int (void*), void*) () from /lib64/libQt5XcbQpa.so.5
#37 0x00007f3a8c40ee3a in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
--Type <return> to continue, or q <return> to quit--
#38 0x00007f3a8c40f1d0 in g_main_context_iterate.isra () from /lib64/libglib-2.0.so.0
#39 0x00007f3a8c40f27c in g_main_context_iteration () from /lib64/libglib-2.0.so.0
#40 0x00007f3a8e3d8cef in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#41 0x00007f3a8e3816ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#42 0x00007f3a8e389ddc in QCoreApplication::exec() () from /lib64/libQt5Core.so.5
#43 0x0000000000408f7c in main (argc=2, argv=<optimized out>) at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/app/main.cpp:532

gdb) frame 18
#18 FakeVim::Internal::FakeVimHandler::Private::commitInsertState (this=this@entry=0xca44dc0)
at /home/twm/tmp/qt-creator-opensource-src-3.6.1-modified/src/plugins/fakevim/fakevimhandler.cpp:2587
2587 lastInsertion.prepend(QString(_("<BS>")).repeated(insertState.backspaces));
(gdb) print lastInsert
No symbol "lastInsert" in current context.
(gdb) print lastInsertion
$1 = (QString &) @0xca45450: {static null =

{<No data fields>}, d = 0x7f3a8e450120 <QArrayData::shared_null>}
(gdb) print insertState.backspaces
$2 = 237518368
(gdb) print insertState
$3 = (FakeVim::Internal::FakeVimHandler::Private::BufferData::InsertState &) @0xca45420: {pos1 = 220221008, pos2 = 0, backspaces = 237518368, deletes = 0, spaces = {
q_hash = d = 0x7f3a8e451260 <QHashData::shared_null>, e = 0x7f3a8e451260 <QHashData::shared_null>}, insertingSpaces = 240, textBeforeCursor = {
static null = {<No data fields>}

, d = 0x7f3a8e450120 <QArrayData::shared_null>}, newLineBefore = 161, newLineAfter = true}
(gdb) print lastInsertion
$4 = (QString &) @0xca45450: {static null =

{<No data fields>}

, d = 0x7f3a8e450120 <QArrayData::shared_null>}

Thanks