https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123797
--- Comment #2 from kongmingd234 <kongmingd234 at proton dot me> --- It could be because I do not have the latest build of GCC from trunk. Or it could be because your test case is different from mine. I should have attached a file containing the code. Is it not there? It should just be. g++ -fmodules -fmodule-mapper=mapper.txt with -x c++-header for the headers. Come to think of it, I may not have added the module mapper for the headers? I will try again and get back to you.
