https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116802
--- Comment #9 from Tymi <tymi at tymi dot org> --- It is indeed not related to whether Clang compiles or not. I used clang as a reference that this is not an issue with other compilers, not as the base of the issue. The base of the issue, is that I have forgotten about ctype::is existence. After looking at the error message, I saw "__ct.is" and thought "reserved keyword, matched with a regular keyword probably an implementation-detail". Which was inherently wrong and naive of me. I apologise for taking your time.
