template <class FormatCallback>
void formatString(StringPiece val, FormatArg& arg, FormatCallback& cb) {
if (arg.width != FormatArg::kDefaultWidth && arg.width < 0) {
template <class FormatCallback>
void formatString(StringPiece val, FormatArg& arg, FormatCallback& cb) {
if (arg.width != FormatArg::kDefaultWidth && arg.width < 0) {