SUMMARY
***
If Qt compiled with asserts enabled then plasmashell crashes almost every time on drag'n'drop any icon on desktop.
***


STEPS TO REPRODUCE
1.  start dragging any *.desktop file on desktop


OBSERVED RESULT
get a crash on drop

EXPECTED RESULT
icon moved

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma:  Gentoo
(available in About System)
KDE Plasma Version:  5.27.10
KDE Frameworks Version: 
Qt Version: 5.15.12

ADDITIONAL INFORMATION
#0  0x00007f0e6e6b1b1c in ??? () at /usr/lib64/libc.so.6
#1  0x00007f0e6e663512 in raise () at /usr/lib64/libc.so.6
#2  0x00007f0e70fe782d in KCrash::defaultCrashHandler(int) () at /usr/lib64/libKF5Crash.so.5
#3  0x00007f0e6e6635b0 in <signal handler called> () at /usr/lib64/libc.so.6
#4  0x00007f0e6e6b1b1c in ??? () at /usr/lib64/libc.so.6
#5  0x00007f0e6e663512 in raise () at /usr/lib64/libc.so.6
#6  0x00007f0e6e64c4ed in abort () at /usr/lib64/libc.so.6
#7  0x00007f0e6ec92d6d in QMessageLogger::fatal(char const*, ...) const () at /usr/lib64/libQt5Core.so.5
#8  0x00007f0e6ec918d2 in qt_assert(char const*, char const*, int) () at /usr/lib64/libQt5Core.so.5
#9  0x00007f0e6ecb24e8 in ??? () at /usr/lib64/libQt5Core.so.5
#10 0x00007f0e600b8451 in Positioner::move(QList<QVariant> const&) () at /usr/lib64/qt5/qml/org/kde/private/desktopcontainment/folder/libfolderplugin.so
#11 0x00007f0e600946bf in Positioner::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) () at /usr/lib64/qt5/qml/org/kde/private/desktopcontainment/folder/libfolderplugin.so
#12 0x00007f0e600951f3 in Positioner::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib64/qt5/qml/org/kde/private/desktopcontainment/folder/libfolderplugin.so
#13 0x00007f0e704cb233 in ??? () at /usr/lib64/libQt5Qml.so.5
#14 0x00007f0e703a55f9 in ??? () at /usr/lib64/libQt5Qml.so.5
#15 0x00007f0e703a750b in QV4::QObjectMethod::callInternal(QV4::Value const*, QV4::Value const*, int) const () at /usr/lib64/libQt5Qml.so.5
#16 0x00007f0e703c3e92 in ??? () at /usr/lib64/libQt5Qml.so.5
#17 0x00007f0e703c758f in ??? () at /usr/lib64/libQt5Qml.so.5
#18 0x00007f0e703595ed in QV4::Function::call(QV4::Value const*, QV4::Value const*, int, QV4::ExecutionContext const*) () at /usr/lib64/libQt5Qml.so.5
#19 0x00007f0e704e60ad in QQmlJavaScriptExpression::evaluate(QV4::CallData*, bool*) () at /usr/lib64/libQt5Qml.so.5
#20 0x00007f0e7049657f in QQmlBoundSignalExpression::evaluate(void**) () at /usr/lib64/libQt5Qml.so.5
#21 0x00007f0e70497cd0 in ??? () at /usr/lib64/libQt5Qml.so.5
#22 0x00007f0e704cad15 in QQmlNotifier::emitNotify(QQmlNotifierEndpoint*, void**) () at /usr/lib64/libQt5Qml.so.5
#23 0x00007f0e6eeee59d in ??? () at /usr/lib64/libQt5Core.so.5
#24 0x00007f0e600908fd in FolderModel::move(int, int, QList<QUrl>) () at /usr/lib64/qt5/qml/org/kde/private/desktopcontainment/folder/libfolderplugin.so
#25 0x00007f0e600a4588 in FolderModel::drop(QQuickItem*, QObject*, int, bool) () at /usr/lib64/qt5/qml/org/kde/private/desktopcontainment/folder/libfolderplugin.so
#26 0x00007f0e60094df3 in FolderModel::qt_metacall(QMetaObject::Call, int, void**) () at /usr/lib64/qt5/qml/org/kde/private/desktopcontainment/folder/libfolderplugin.so


sometimes it also show this in the logs
фев 26 11:45:42 rionpc plasmashell[83588]: ASSERT: "last < rowCount(parent)" in file /var/tmp/portage/dev-qt/qtcore-5.15.12-r2/work/qtbase-everywhere-src-5.15.12/src/corelib/itemmodels/qabstractitemmodel.cpp, l>
фев 26 11:45:42 rionpc plasmashell[83588]: 25 -- exe=/usr/bin/plasmashell
фев 26 11:45:42 rionpc plasmashell[83588]: 13 -- platform=xcb
фев 26 11:45:42 rionpc plasmashell[83588]: 11 -- display=:0
фев 26 11:45:42 rionpc plasmashell[83588]: 20 -- appname=plasmashell
фев 26 11:45:42 rionpc plasmashell[83588]: 17 -- apppath=/usr/bin
фев 26 11:45:42 rionpc plasmashell[83588]: 9 -- signal=6
фев 26 11:45:42 rionpc plasmashell[83588]: 10 -- pid=83588
фев 26 11:45:42 rionpc plasmashell[83588]: 19 -- appversion=5.27.10
фев 26 11:45:42 rionpc plasmashell[83588]: 19 -- programname=Plasma
фев 26 11:45:42 rionpc plasmashell[83588]: 31 -- bugaddress=submit@bugs.kde.org