https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93545
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Created attachment 47768 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47768&action=edit gcc10-pr93545-2.patch As discussed on IRC, here is incremental patch to reject __has_include outside of preprocessing directives (which we in 9 and earlier didn't allow and aren't valid in C++).