https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125775
--- Comment #2 from Maxim Dementyev <maxxdem2020 at gmail dot com> --- I don't think a warning option should have any effects besides giving you warnings. Moreover, I don't see anything wrong with my example. It is the most trivial PCH usage I can think of. Also, __cpp_runtime_arrays is a macro related to a nonstandard feature. Could it be __cpp_runtime_arrays is used somewhere in headers included by #include <iostream>, triggering the warning?
