Maybe I’m missing something.
Imagine that we have this setup:
a.cpp, uses symbols from
| x.h
| y.h
b.cpp, uses symbols from
| x.h
| y.h
| z.h
module.cpp, contains
#include "a.cpp"
#include "b.cpp"
Now, we try building the module. We start by adding the x.h and y.h headers to a.cpp and rebuild. There are no build errors in a.cpp, but we see some undefined symbols in b.cpp. It looks like the z.h header is missing from b.cpp, but we don’t get any warning that x.h and y.h are also used in that file, because they already got included in a.cpp.
I think in this scenario, after running the steps you suggested, completion would still be broken in b.cpp, (it would only include z.h) even though the build would work.
Did I miss a step that would guarantee b.cpp would actually get the required x.h and y.h includes?