https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85821
--- Comment #8 from Andrey Bolshakov <bolsh.andrey at yandex dot ru> --- Thanks, interesting! Personally, (as you may guess) I don't like option B. It would contradict with the <chrono> header synopsis (please don't forget about the "as if" rule). IWYU project has a script for parsing standard library header synopses and generating a symbol mapping based on them: https://github.com/include-what-you-use/include-what-you-use/blob/1062e431229a833d092ff98917ff8888e850ec33/mapgen/iwyu-mapgen-std-symbol.py
