[Bug libstdc++/65420] New: Enumerators in std::regex_constants should be constexpr variables instead

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65420

            Bug ID: 65420
           Summary: Enumerators in std::regex_constants should be
                    constexpr variables instead
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org

28.5 [re.const] says the members of namespace std::regex_constants should be
variables, not enumerators.

The difference is observable, as perverse users could try to take their
addresses.