In the .cpp generated by qml, include qcoreapplication.h without module dir variant

After I run command 

"qmlcachegen.exe" --resource="F:\tmp\test.qrc" -o "F:\tmp\test.qml.AEA2B4E2.cpp" "F:\tmp\test\test.qml"

in test.qml.AEA2B4E2.cpp, qcoreapplication.h is included without "QtCore/". But the other header files are included with their module directory. 

I attach the qml files which can reproduce this problem.