I'm currently on bionic user edition, upgraded with no issues as described at:  
https://community.kde.org/Neon/BionicUpgrades. 

I'm trying to compile kate from source with the following commands

$ apt source kate 
$ sudo apt build-dep kate 
$ cd kate-18.08.1/
$ mkdir build
$ cd build/
$ cmake .. -DCMAKE_INSTALL_PREFIX=$(kf5-config --prefix)
$ make -j$(nproc)

which fails with the following error message

[ 41%] Linking CXX shared module tabswitcherplugin.so
[ 41%] Built target tabswitcherplugin
[ 41%] Building CXX object addons/kate-ctags/CMakeFiles/katectagsplugin.dir/qrc_plugin.cpp.o
[ 41%] Building CXX object addons/search/CMakeFiles/katesearchplugin.dir/FolderFilesList.cpp.o
/usr/lib/x86_64-linux-gnu/libKF5TextEditor.so.5.50.0: undefined reference to `QAbstractItemView::eventFilter(QObject*, QEvent*)@Qt_5'
/usr/lib/x86_64-linux-gnu/libKF5TextEditor.so.5.50.0: undefined reference to `QTreeView::verticalScrollbarValueChanged(int)@Qt_5'
/usr/lib/x86_64-linux-gnu/libKF5KIOCore.so.5.50.0: undefined reference to `QtPrivate::QStringList_contains(QStringList const*, QLatin1String, Qt::CaseSensitivity)@Qt_5'
/usr/lib/x86_64-linux-gnu/libKF5Crash.so.5.50.0: undefined reference to `QString::arg(QLatin1String, int, QChar) const@Qt_5'
/usr/lib/x86_64-linux-gnu/libKF5TextEditor.so.5.50.0: undefined reference to `qt_version_tag@Qt_5.11'
/usr/lib/x86_64-linux-gnu/libKF5CoreAddons.so.5.50.0: undefined reference to `QMetaObject::invokeMethodImpl(QObject*, QtPrivate::QSlotObjectBase*, Qt::ConnectionType, void*)@Qt_5'
collect2: error: ld returned 1 exit status
kwrite/CMakeFiles/kwrite.dir/build.make:177: recipe for target 'kwrite/kwrite' failed
make[2]: *** [kwrite/kwrite] Error 1
CMakeFiles/Makefile2:1477: recipe for target 'kwrite/CMakeFiles/kwrite.dir/all' failed
make[1]: *** [kwrite/CMakeFiles/kwrite.dir/all] Error 2