[Bug libstdc++/90246] std::bad_variant_access messages are not useful

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90246

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Author: redi
Date: Fri May 17 14:36:37 2019
New Revision: 271326

URL: https://gcc.gnu.org/viewcvs?rev=271326&root=gcc&view=rev
Log:
PR libstdc++/90246 Improve text of std::variant exceptions and assertions

        PR libstdc++/90246
        * include/std/variant (holds_alternative, get, get_if): Improve
        static assertion messages.
        (bad_variant_access::bad_variant_access()): Change default message.
        (__throw_bad_variant_access(bool)): New overload.
        (get): Use new overload.
        (visit, visit<R>): Improve exception message.

Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/std/variant