Insert mode works fine, but when I press any letter (like q) after the colon, it crashes.

Reproducible: Always

Steps to Reproduce:
1. Open Kate
2. Switch to VI Mode
3. Input a colon (:) and press any letter (like q).

Actual Results:  
Crashed (segfault).

Expected Results:  
the letter (q) appears in the text area.

Kate 14.12.2
KF5 5.7.0
Qt 5.4.1

backtrace:
#0  0x00007ffff74ac6a0 in ?? () from /usr/lib/libKF5TextEditor.so.5
#1  0x00007ffff74ad94f in ?? () from /usr/lib/libKF5TextEditor.so.5
#2  0x00007ffff74a3df9 in KateVi::EmulatedCommandBar::rangeExpression() () from /usr/lib/libKF5TextEditor.so.5
#3  0x00007ffff74a3e87 in KateVi::EmulatedCommandBar::withoutRangeExpression() () from /usr/lib/libKF5TextEditor.so.5
#4  0x00007ffff74a77f9 in KateVi::EmulatedCommandBar::editTextChanged(QString const&) () from /usr/lib/libKF5TextEditor.so.5
#5  0x00007ffff3b2e309 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQt5Core.so.5
#6  0x00007ffff4533022 in QLineEdit::textChanged(QString const&) () from /usr/lib/libQt5Widgets.so.5
#7  0x00007ffff4537739 in ?? () from /usr/lib/libQt5Widgets.so.5
#8  0x00007ffff3b2e309 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQt5Core.so.5
#9  0x00007ffff4792bb5 in QWidgetLineControl::textChanged(QString const&) () from /usr/lib/libQt5Widgets.so.5
#10 0x00007ffff45c699f in QWidgetLineControl::finishChange(int, bool, bool) () from /usr/lib/libQt5Widgets.so.5
#11 0x00007ffff45c92bb in QWidgetLineControl::processKeyEvent(QKeyEvent*) () from /usr/lib/libQt5Widgets.so.5
#12 0x00007ffff453317a in QLineEdit::keyPressEvent(QKeyEvent*) () from /usr/lib/libQt5Widgets.so.5
#13 0x00007ffff4428074 in QWidget::event(QEvent*) () from /usr/lib/libQt5Widgets.so.5
#14 0x00007ffff4539729 in QLineEdit::event(QEvent*) () from /usr/lib/libQt5Widgets.so.5
#15 0x00007ffff43e4acc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#16 0x00007ffff43eab19 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#17 0x00007ffff74ab089 in KateVi::EmulatedCommandBar::handleKeyPress(QKeyEvent const*) () from /usr/lib/libKF5TextEditor.so.5
#18 0x00007ffff7492c7d in KateVi::InputModeManager::handleKeypress(QKeyEvent const*) () from /usr/lib/libKF5TextEditor.so.5
#19 0x00007ffff3afdb04 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#20 0x00007ffff43e4aac in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#21 0x00007ffff43eab19 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#22 0x00007ffff3afdd1b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#23 0x00007ffff74931f0 in KateVi::InputModeManager::feedKeyPresses(QString const&) const () from /usr/lib/libKF5TextEditor.so.5
#24 0x00007ffff74af65e in KateVi::KeyMapper::playBackRejectedKeys() () from /usr/lib/libKF5TextEditor.so.5
#25 0x00007ffff74afc90 in KateVi::KeyMapper::handleKeypress(QChar) () from /usr/lib/libKF5TextEditor.so.5
#26 0x00007ffff7492c10 in KateVi::InputModeManager::handleKeypress(QKeyEvent const*) () from /usr/lib/libKF5TextEditor.so.5
#27 0x00007ffff3afdb04 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#28 0x00007ffff43e4aac in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#29 0x00007ffff43eab19 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#30 0x00007ffff3afdd1b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#31 0x00007ffff444268b in ?? () from /usr/lib/libQt5Widgets.so.5
#32 0x00007ffff43e4acc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#33 0x00007ffff43e9f10 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#34 0x00007ffff3afdd1b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#35 0x00007ffff3e293e1 in QGuiApplicationPrivate::processKeyEvent(QWindowSystemInterfacePrivate::KeyEvent*) () from /usr/lib/libQt5Gui.so.5
#36 0x00007ffff3e2e2e5 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) ()
   from /usr/lib/libQt5Gui.so.5
#37 0x00007ffff3e131ef in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Gui.so.5
#38 0x00007fffe44ed1d0 in ?? () from /usr/lib/qt/plugins/platforms/libqxcb.so
#39 0x00007fffefcf171d in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#40 0x00007fffefcf1a08 in ?? () from /usr/lib/libglib-2.0.so.0
#41 0x00007fffefcf1abc in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
---Type <return> to continue, or q <return> to quit---
#42 0x00007ffff3b56077 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#43 0x00007ffff3afb7b2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#44 0x00007ffff3b0318c in QCoreApplication::exec() () from /usr/lib/libQt5Core.so.5
#45 0x00007ffff7bacd94 in kdemain () from /usr/lib/libkdeinit5_kate.so
#46 0x00007ffff77a0800 in __libc_start_main () from /usr/lib/libc.so.6
#47 0x000000000040076e in _start ()