45 template <typename Char> struct formatter<test_struct, Char> {  struct
47   auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {  in parse()
51   auto format(test_struct, format_context& ctx) -> decltype(ctx.out()) {  in format()
427 template <> struct formatter<custom_type> {  struct
428   auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {  in parse()
433   auto format(const custom_type& p, FormatContext& ctx) -> decltype(ctx.out()) {  in format()
534 template <> struct formatter<copy_throwable> {  struct
535   auto parse(format_parse_context& ctx) const -> decltype(ctx.begin()) {  in parse()
538   auto format(copy_throwable, format_context& ctx) -> decltype(ctx.out()) {  in format()
598 template <> struct formatter<enabled_formatter> {  struct
602   auto format(enabled_formatter, format_context& ctx) -> decltype(ctx.out()) {  in format()  argument
626 template <> struct formatter<convertible_to_int> {  struct
635 template <> struct formatter<convertible_to_c_string> {  argument
636   auto parse(format_parse_context& ctx) -> decltype(ctx.begin()) {  in parse()
639   auto format(convertible_to_c_string, format_context& ctx)  in format()