C++ 11 regex: regex error std::regex_constants::error_brack

Question

I have the following piece of code:

#include <regex>
#include <exception>
#include <iostream>

int main(int argc, char *argv[])
{
  std::regex reg;
  try{
    reg = std::regex(".*[a-zA-Z]+.*");
  }
  catch(std::regex_error &e){
    std::cout << e.what() << std::endl;
    std::cout << e.code() << std::endl;
    if (e.code() == std::regex_constants::error_brack)
      std::cerr << "The expression contained mismatched brackets ([ and ]).\n";
  }
  return 0;
}

And this gives me :

regex_error
4
The expression contained mismatched brackets ([ and ]).

What am I doing wrong ? I am using g++ 4.8.2 with -std=c++11 flag.

EDIT I get the same on ideone http://ideone.com/SDqv0e so it's not the compiler.