https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114461
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Perhaps given http://eel.is/c++draft/cpp.pre#7 makes the default for preprocessing directives not macro expanded unless otherwise specified, change http://eel.is/c++draft/cpp.module#3 "Any preprocessing tokens after the module preprocessing token in the module directive are processed just as in normal text." to "If pp-module-partition appears in pp-tokens, any preprocessing tokens after the last pp-module-partition token are processed just as in normal text; otherwise if pp-module-name appears in pp-tokens, any preprocessing tokens after the last pp-module-name token are processed just as in normal text." That would make #define EMPTY export module EMPTY ; and #define SEMI export module SEMI ; and #define DOT . export module foo DOT bar ; etc. invalid.
