crash during replace inside selection

#0  0x00007f608983e3b3 in QVector<QScriptLine>::operator[] (this=0x0, i=0)
    at ../../include/QtCore/../../../47/src/corelib/tools/qvector.h:347
#1  0x00007f6089986d7c in QTextLine::naturalTextRect (this=0x7fff468187e0)
    at /home/kamm/dev/qt/47/src/gui/text/qtextlayout.cpp:1454
#2  0x00007f60782b1539 in TextEditor::Internal::TextEditorOverlay::createSelectionPath (this=0x62a0270, 
    begin=..., end=..., clip=...) at /home/kamm/dev/creator/2.1/src/plugins/texteditor/texteditoroverlay.cpp:193
#3  0x00007f60782b2bcf in TextEditor::Internal::TextEditorOverlay::paintSelection (this=0x62a0270, 
    painter=0x7fff46819a40, selection=...)
    at /home/kamm/dev/creator/2.1/src/plugins/texteditor/texteditoroverlay.cpp:322
#4  0x00007f60782b3572 in TextEditor::Internal::TextEditorOverlay::paint (this=0x62a0270, painter=0x7fff46819a40, 
    clip=...) at /home/kamm/dev/creator/2.1/src/plugins/texteditor/texteditoroverlay.cpp:403
#5  0x00007f6078246cfb in TextEditor::BaseTextEditor::paintEvent (this=0x5a22660, e=0x7fff4681a6e0)
    at /home/kamm/dev/creator/2.1/src/plugins/texteditor/basetexteditor.cpp:2444
#6  0x00007f60896d6508 in QWidget::event (this=0x5a22660, event=0x7fff4681a6e0)
    at /home/kamm/dev/qt/47/src/gui/kernel/qwidget.cpp:8406
#7  0x00007f6089ba40ef in QFrame::event (this=0x5a22660, e=0x7fff4681a6e0)
    at /home/kamm/dev/qt/47/src/gui/widgets/qframe.cpp:557
#8  0x00007f6089c560c7 in QAbstractScrollArea::viewportEvent (this=0x5a22660, e=0x7fff4681a6e0)
    at /home/kamm/dev/qt/47/src/gui/widgets/qabstractscrollarea.cpp:1043
#9  0x00007f607824406a in TextEditor::BaseTextEditor::viewportEvent (this=0x5a22660, event=0x7fff4681a6e0)
    at /home/kamm/dev/creator/2.1/src/plugins/texteditor/basetexteditor.cpp:2060
#10 0x00007f6089c56d47 in QAbstractScrollAreaPrivate::viewportEvent (this=0x5a22860, event=0x7fff4681a6e0)
    at /home/kamm/dev/qt/47/src/gui/widgets/qabstractscrollarea_p.h:100
#11 0x00007f6089c56e52 in QAbstractScrollAreaFilter::eventFilter (this=0x5e9b110, o=0x5a21a90, e=0x7fff4681a6e0)
    at /home/kamm/dev/qt/47/src/gui/widgets/qabstractscrollarea_p.h:116
#12 0x00007f608a8243e7 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x1e56060, 
    receiver=0x5a21a90, event=0x7fff4681a6e0) at /home/kamm/dev/qt/47/src/corelib/kernel/qcoreapplication.cpp:846
#13 0x00007f6089666083 in QApplicationPrivate::notify_helper (this=0x1e56060, receiver=0x5a21a90, 
    e=0x7fff4681a6e0) at /home/kamm/dev/qt/47/src/gui/kernel/qapplication.cpp:4458
#14 0x00007f6089665f0d in QApplication::notify (this=0x7fff4681ba50, receiver=0x5a21a90, e=0x7fff4681a6e0)
    at /home/kamm/dev/qt/47/src/gui/kernel/qapplication.cpp:4427
#15 0x00007f608a82413e in QCoreApplication::notifyInternal (this=0x7fff4681ba50, receiver=0x5a21a90, 
    event=0x7fff4681a6e0) at /home/kamm/dev/qt/47/src/corelib/kernel/qcoreapplication.cpp:731
#16 0x00007f608966907b in QCoreApplication::sendSpontaneousEvent (receiver=0x5a21a90, event=0x7fff4681a6e0)
    at ../../include/QtCore/../../../47/src/corelib/kernel/qcoreapplication.h:218
#17 0x00007f60896cdf03 in QWidgetPrivate::drawWidget (this=0x5a22b40, pdev=0x28c24a8, rgn=..., offset=..., 
    flags=4, sharedPainter=0x0, backingStore=0x28c20d0) at /home/kamm/dev/qt/47/src/gui/kernel/qwidget.cpp:5493
#18 0x00007f6089926ce8 in QWidgetBackingStore::sync (this=0x28c20d0)
    at /home/kamm/dev/qt/47/src/gui/painting/qbackingstore.cpp:1325
#19 0x00007f60896c4a55 in QWidgetPrivate::syncBackingStore (this=0x2085660)
    at /home/kamm/dev/qt/47/src/gui/kernel/qwidget.cpp:1843
#20 0x00007f60896d6baa in QWidget::event (this=0x20854e0, event=0x4d354f0)
    at /home/kamm/dev/qt/47/src/gui/kernel/qwidget.cpp:8553
#21 0x00007f6089bc7d91 in QMainWindow::event (this=0x20854e0, event=0x4d354f0)
    at /home/kamm/dev/qt/47/src/gui/widgets/qmainwindow.cpp:1480
#22 0x00007f60896660ac in QApplicationPrivate::notify_helper (this=0x1e56060, receiver=0x20854e0, e=0x4d354f0)
    at /home/kamm/dev/qt/47/src/gui/kernel/qapplication.cpp:4462
#23 0x00007f6089665f0d in QApplication::notify (this=0x7fff4681ba50, receiver=0x20854e0, e=0x4d354f0)
    at /home/kamm/dev/qt/47/src/gui/kernel/qapplication.cpp:4427
#24 0x00007f608a82413e in QCoreApplication::notifyInternal (this=0x7fff4681ba50, receiver=0x20854e0, 

(gdb) p line
$14 = {i = 0, eng = 0x0}
(gdb) p *blockLayout
$15 = {d = 0x5450b00}

beginChar = begin.positionInBlock();
line = blockLayout->lineForTextPosition(beginChar);