Method check_sign

extlibs/fmt/include/fmt/format.h:2120–2126

  }

  FMT_CONSTEXPR void check_sign() {
    require_numeric_argument();
    if (is_integral_type(arg_type_) && arg_type_ != type::int_type &&
        arg_type_ != type::long_long_type && arg_type_ != type::char_type) {
      error_handler_.on_error("format specifier requires signed argument");
    }
  }

  FMT_CONSTEXPR void check_precision() {
    if (is_integral_type(arg_type_) || arg_type_ == type::pointer_type)