https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116827
--- Comment #6 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #5) > > #if defined(__has_feature) && __has_feature(modules) > > This is a bug. If __has_feature is _not_ define, then __has_feature(modules) > would not compile Definitely agree, I had missed that, thanks for highlighting it. Every year some more examples crop up into the SDKs, and every year I report them. Reported the examples in macOS 15.0 SDK as FB15255066 A copy of that report is available there: https://gist.github.com/fxcoudert/1e3ed3470febf220a392152189c143a3 > It looks like the header now assumes that if __has_feature(modules) is true, > then they're compiling with Clang. Which is not true because GCC supports > __has_feature now. Before I report this to Apple, I want to have an opinion: Iain, what do you think is the best fix there? Do we want to suggest Apple not bypass USE_CLANG_TYPES on GCC?