https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56665
--- Comment #8 from Bogdan Slusarczyk <bodzio131 at op dot pl> --- (In reply to Nikita Kniazev from comment #6) > This is not a GCC bug. The examples above have use after scope bug. > Look at `assign_a` documentation > https://www.boost.org/doc/libs/1_69_0/libs/spirit/classic/doc/ > predefined_actors.html it takes a value by reference (by const reference > actually). How does example use "after scope bug" as 'variable' is all the time in the same scope as assign_a ?