From 13d4f8469e885a0cbf83a647f91a60767d72e461 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@meta.com>
Date: Sun, 31 Aug 2025 10:02:36 -0700
Subject: [PATCH] Remove deprecated vformat_to

---
 include/fmt/format-inl.h |  4 ++--
 include/fmt/format.h     | 18 +-----------------
 include/fmt/xchar.h      | 20 +++++++++++++++-----
 src/format.cc            |  5 +----
 4 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/include/fmt/format-inl.h b/include/fmt/format-inl.h
index 527a5bb1..6737e1d0 100644
--- a/include/fmt/format-inl.h
+++ b/include/fmt/format-inl.h
@@ -1463,8 +1463,8 @@ FMT_FUNC void vformat_to(buffer<char>& buf, string_view fmt, format_args args,
   auto out = appender(buf);
   if (fmt.size() == 2 && equal2(fmt.data(), "{}"))
     return args.get(0).visit(default_arg_formatter<char>{out});
-  parse_format_string(
-      fmt, format_handler<char>{parse_context<char>(fmt), {out, args, loc}});
+  parse_format_string(fmt,
+                      format_handler<>{parse_context<>(fmt), {out, args, loc}});
 }
 
 template <typename T> struct span {
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 54067946..b766c08b 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3753,7 +3753,7 @@ template <typename Char> struct udl_arg {
 };
 #endif  // FMT_USE_NONTYPE_TEMPLATE_ARGS
 
-template <typename Char> struct format_handler {
+template <typename Char = char> struct format_handler {
   parse_context<Char> parse_ctx;
   buffered_context<Char> ctx;
 
@@ -3819,22 +3819,6 @@ FMT_CONSTEXPR auto native_formatter<T, Char, TYPE>::format(
                       specs_.precision_ref, ctx);
   return write<Char>(ctx.out(), val, specs, ctx.locale());
 }
-
-// DEPRECATED!
-template <typename Char = char> struct vformat_args {
-  using type = basic_format_args<buffered_context<Char>>;
-};
-template <> struct vformat_args<char> {
-  using type = format_args;
-};
-
-template <typename Char>
-void vformat_to(buffer<Char>& buf, basic_string_view<Char> fmt,
-                typename vformat_args<Char>::type args, locale_ref loc = {}) {
-  auto out = basic_appender<Char>(buf);
-  parse_format_string(
-      fmt, format_handler<Char>{parse_context<Char>(fmt), {out, args, loc}});
-}
 }  // namespace detail
 
 FMT_BEGIN_EXPORT
diff --git a/include/fmt/xchar.h b/include/fmt/xchar.h
index df5dc926..51c5cfc1 100644
--- a/include/fmt/xchar.h
+++ b/include/fmt/xchar.h
@@ -55,6 +55,16 @@ inline auto write_loc(basic_appender<wchar_t> out, loc_value value,
 #endif
   return false;
 }
+
+template <typename Char>
+void vformat_to(buffer<Char>& buf, basic_string_view<Char> fmt,
+                basic_format_args<buffered_context<Char>> args,
+                locale_ref loc = {}) {
+  static_assert(!std::is_same<Char, char>::value, "");
+  auto out = basic_appender<Char>(buf);
+  parse_format_string(
+      fmt, format_handler<Char>{parse_context<Char>(fmt), {out, args, loc}});
+}
 }  // namespace detail
 
 FMT_BEGIN_EXPORT
@@ -153,7 +163,7 @@ auto join(const Tuple& tuple, basic_string_view<wchar_t> sep)
 
 template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
 auto vformat(basic_string_view<Char> fmt,
-             typename detail::vformat_args<Char>::type args)
+             basic_format_args<buffered_context<Char>> args)
     -> std::basic_string<Char> {
   auto buf = basic_memory_buffer<Char>();
   detail::vformat_to(buf, fmt, args);
@@ -186,7 +196,7 @@ auto format(const S& fmt, T&&... args) -> std::basic_string<Char> {
 template <typename S, typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
 inline auto vformat(locale_ref loc, const S& fmt,
-                    typename detail::vformat_args<Char>::type args)
+                    basic_format_args<buffered_context<Char>> args)
     -> std::basic_string<Char> {
   auto buf = basic_memory_buffer<Char>();
   detail::vformat_to(buf, detail::to_string_view(fmt), args, loc);
@@ -207,7 +217,7 @@ template <typename OutputIt, typename S,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                             detail::is_exotic_char<Char>::value)>
 auto vformat_to(OutputIt out, const S& fmt,
-                typename detail::vformat_args<Char>::type args) -> OutputIt {
+                basic_format_args<buffered_context<Char>> args) -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
   detail::vformat_to(buf, detail::to_string_view(fmt), args);
   return detail::get_iterator(buf, out);
@@ -228,7 +238,7 @@ template <typename S, typename OutputIt, typename... Args,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                             detail::is_exotic_char<Char>::value)>
 inline auto vformat_to(OutputIt out, locale_ref loc, const S& fmt,
-                       typename detail::vformat_args<Char>::type args)
+                       basic_format_args<buffered_context<Char>> args)
     -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
   vformat_to(buf, detail::to_string_view(fmt), args, loc);
@@ -249,7 +259,7 @@ template <typename OutputIt, typename Char, typename... Args,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                             detail::is_exotic_char<Char>::value)>
 inline auto vformat_to_n(OutputIt out, size_t n, basic_string_view<Char> fmt,
-                         typename detail::vformat_args<Char>::type args)
+                         basic_format_args<buffered_context<Char>> args)
     -> format_to_n_result<OutputIt> {
   using traits = detail::fixed_buffer_traits;
   auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);
diff --git a/src/format.cc b/src/format.cc
index 50e267c5..05d0105b 100644
--- a/src/format.cc
+++ b/src/format.cc
@@ -30,16 +30,13 @@ template FMT_API auto decimal_point_impl(locale_ref) -> char;
 // DEPRECATED!
 template FMT_API void buffer<char>::append(const char*, const char*);
 
-// DEPRECATED!
-template FMT_API void vformat_to(buffer<char>&, string_view,
-                                 typename vformat_args<>::type, locale_ref);
-
 // Explicit instantiations for wchar_t.
 
 template FMT_API auto thousands_sep_impl(locale_ref)
     -> thousands_sep_result<wchar_t>;
 template FMT_API auto decimal_point_impl(locale_ref) -> wchar_t;
 
+// DEPRECATED!
 template FMT_API void buffer<wchar_t>::append(const wchar_t*, const wchar_t*);
 
 }  // namespace detail