问boost::spirit::qi::phrase_parse中某些未定义的行为

EN

auto parser = qi::double_ >> *(',' >> qi::double_);

#include <boost/spirit/include/qi.hpp>

#include <iostream>
#include <string>

namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;

const auto doubles_parser_global = qi::double_ >> *(',' >> qi::double_);

int main() {
    const auto doubles_parser_local = qi::double_ >> *(',' >> qi::double_);

    const std::string nums {"3.14, 3.15, 3.1415926"};

    std::cout << std::boolalpha;

    std::cout
        << qi::phrase_parse(
            nums.cbegin(), nums.cend(), doubles_parser_local, ascii::space
        )
        << std::endl;                             // works fine

    std::cout
        << qi::phrase_parse(
            nums.cbegin(), nums.cend(), doubles_parser_global, ascii::space
        )                                         // this segfaults
        << std::endl;
}