When a file includes the generated moc output for a header file as well as its own generated moc output then it will fail to build

When a file includes the generated moc output for a header file as well as its own generated moc output then it will fail to build. For example if it has:

#include "moc_foo.cpp"
#include "foo.moc"

then it will have compile errors or linker errors. Using qmake directly works fine.