[Bug libstdc++/102447] New: std::regex incorrectly accepts invalid bracket expression

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102447

            Bug ID: 102447
           Summary: std::regex incorrectly accepts invalid bracket
                    expression
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
            Blocks: 102445
  Target Milestone: ---

#include <regex>
#include <cassert>

int main()
{
  try {
    std::regex{"[\\w-a]"};
    assert(!"here");
  } catch (const std::regex_error& e) {
    assert(e.code() == std::regex_constants::error_range);
  }
}

This should run and exit successfully, but with GCC we get:

a.out: reg.C:8: int main(): Assertion `!"here"' failed.
Aborted (core dumped)


The bracket expression [\w-a] is invalid.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102445
[Bug 102445] [meta-bug] std::regex issues