MOC fails silently on missing includes

MOC seem to fail silently on missing #include headers. This causes sporadic problems with missing macro expansions in our SW that trigger hard-to-understand errors later in the build process.

Reproducer project attached. The reproducer might appear artificial, but it's based on real-life problems where the missing header first appear after the MOC run, but before the C++ compiler run. This causes the build succeed, despite MOC not expanding macros found in the missing header.

 Can you please make MOC more strict, so that it fails immediately when headers are not found?