https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66343
--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The #c3 testcase works now, so if you have something different you can reproduce it on, please attach preprocessed source for the PCH header and preprocessed source of the c/c++ source with the PCH header unincluded plus command lines.