[Bug libstdc++/67362] New: std::regex("((.)", std::regex_constants::basic) throws

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67362

            Bug ID: 67362
           Summary: std::regex("((.)", std::regex_constants::basic) throws
           Product: gcc
           Version: 4.9.4
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: timshen at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

#include <regex>
#include <iostream>

int main()
{
  std::regex re("((.)", std::regex_constants::basic);
}


terminate called after throwing an instance of 'std::regex_error'
  what():  regex_error
Aborted (core dumped)


For a POSIX BRE neither '(' nor ')' should be special, so this should not fail.