Are you looking to do error-checking and error-prevention by ensuring (before "shipping" an application) that all your C++ types that should be registered are, indeed, actually properly registered?
If that is your goal, then I commend you. I am interested in that topic as well.
So far, I have been able to greatly increase detection of many such issues using a combination of:total ban on "qml warnings". (things that qml prints as "warnings" tend to be what I consider fatal bugs). launch the application during automated testing use automated scripts to scan the output of the launched application for any forbidden output such as "unregistered datatype" and "failed to load component"
The ban on warnings that I mention in point (1) is achieved by installing (in C++) a Qt custom message handler to spy on all logged messages and abort if any messages are "warnings" emanating from a qml file: https://github.com/219-design/qt-qml-project-template-with-ci/blob/4d81552d77/src/app/qml_message_interceptor.cc#L44
Launching the application during C.I. on a headless machine is done with Xvfb: https://github.com/219-design/qt-qml-project-template-with-ci/blob/4d81552d772c32b7d62edb4b4f0f678ca92bed4f/run_all_tests.sh#L50
The warnings-ban could be used on any platform.
The Xvfb automation, to my knowledge, would be limited to Linux applications. Therefore a parser-based detection system could be a more cross-platform portable solution.
If you come up with a parsing-based solution, I'm sure that I and many other users that combine C++ with QML would be happy to try out your solution.