https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105595
--- Comment #9 from dennis-hezel at gmx dot de --- Yes it is also true for functions in anon namespace inside header. Again, I am not so concerned with getting all of those scenarios perfectly fixed. Like you were saying, it probably requires some integration with LTO. Getting spammed with these suboject linkage warning related to coroutines for 2.5 years now is starting it get annoying. A fix just for coroutines would be greatly appreciated.
