https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61601
--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #13)
> The second one is rejected because {2444444444} is too large. It throws
> error_backref but maybe that should be error_space as well.
See Bug 123895 for that.
