Remove legacy workaround

include/fmt/core.h

@@ -1901,12 +1901,7 @@ using is_formattable = bool_constant<!std::is_base_of<
   \endrst
  */
 template <typename Context, size_t NUM_NAMED_ARGS, typename... Args>
-class format_arg_store_impl
+class format_arg_store_impl {
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-    // Workaround a GCC template argument substitution bug.
-    : public basic_format_args<Context>
-#endif
-{
  private:
   static const size_t num_args = sizeof...(Args);
   static const bool is_packed = num_args <= detail::max_packed_args;
@@ -1923,11 +1918,7 @@ class format_arg_store_impl
  public:
   template <typename... T>
   FMT_CONSTEXPR FMT_INLINE format_arg_store_impl(T&... args)
-      :
+      : args_{value_type(named_args_, NUM_NAMED_ARGS),
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-        basic_format_args<Context>(*this),
-#endif
-        args_{value_type(named_args_, NUM_NAMED_ARGS),
               detail::make_arg<is_packed, Context>(args)...} {
     detail::init_named_args(named_args_, 0, 0, args...);
   }
@@ -1944,13 +1935,9 @@ class format_arg_store_impl
   }
 };
 
+// A specialization of format_arg_store_impl without named arguments.
 template <typename Context, typename... Args>
-class format_arg_store_impl<Context, 0, Args...>
+class format_arg_store_impl<Context, 0, Args...> {
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-    // Workaround a GCC template argument substitution bug.
-    : public basic_format_args<Context>
-#endif
-{
  private:
   static const size_t num_args = sizeof...(Args);
   static const bool is_packed = num_args <= detail::max_packed_args;
@@ -1964,12 +1951,7 @@ class format_arg_store_impl<Context, 0, Args...>
  public:
   template <typename... T>
   FMT_CONSTEXPR FMT_INLINE format_arg_store_impl(T&... args)
-      :
+      : args_{detail::make_arg<is_packed, Context>(args)...} {}
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-        basic_format_args<Context>(*this),
-#endif
-        args_{detail::make_arg<is_packed, Context>(args)...} {
-  }
 
   static constexpr unsigned long long desc =
       (is_packed ? detail::encode_types<Context, Args...>()
@@ -1986,10 +1968,10 @@ using format_arg_store =
 
 /**
   \rst
-  Constructs a `~fmt::format_arg_store` object that contains references to
+  Constructs an object that stores references to arguments and can be implicitly
-  arguments and can be implicitly converted to `~fmt::format_args`. `Context`
+  converted to `~fmt::format_args`. `Context` can be omitted in which case it
-  can be omitted in which case it defaults to `~fmt::format_context`.
+  defaults to `~fmt::format_context`. See `~fmt::arg` for lifetime
-  See `~fmt::arg` for lifetime considerations.
+  considerations.
   \endrst
  */
 // Take arguments by lvalue references to avoid some lifetime issues, e.g.
@@ -2739,7 +2721,8 @@ template <> struct vformat_args<char> {
   using type = format_args;
 };
 
-// Use vformat_args and avoid type_identity to keep symbols short.
+// Use vformat_args and avoid type_identity, keep symbols short and workaround
+// a GCC <= 4.8 bug.
 template <typename Char>
 void vformat_to(buffer<Char>& buf, basic_string_view<Char> fmt,
                 typename vformat_args<Char>::type args, locale_ref loc = {});

include/fmt/format.h

@@ -3969,7 +3969,7 @@ template <typename Char> struct udl_arg {
 
 template <typename Locale, typename Char>
 auto vformat(const Locale& loc, basic_string_view<Char> fmt,
-             basic_format_args<buffer_context<type_identity_t<Char>>> args)
+             typename detail::vformat_args<Char>::type args)
     -> std::basic_string<Char> {
   auto buf = basic_memory_buffer<Char>();
   detail::vformat_to(buf, fmt, args, detail::locale_ref(loc));

include/fmt/ostream.h

@@ -193,7 +193,7 @@ inline void vprint_directly(std::ostream& os, string_view format_str,
 FMT_EXPORT template <typename Char>
 void vprint(std::basic_ostream<Char>& os,
             basic_string_view<type_identity_t<Char>> format_str,
-            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+            typename detail::vformat_args<Char>::type args) {
   auto buffer = basic_memory_buffer<Char>();
   detail::vformat_to(buffer, format_str, args);
   if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;

include/fmt/printf.h

@@ -586,10 +586,13 @@ inline auto make_wprintf_args(const T&... args)
   return {args...};
 }
 
+template <typename Char> struct vprintf_args {
+  using type = basic_format_args<basic_printf_context<Char>>;
+};
+
 template <typename Char>
-inline auto vsprintf(
+inline auto vsprintf(basic_string_view<Char> fmt,
-    basic_string_view<Char> fmt,
+                     typename vprintf_args<Char>::type args)
-    basic_format_args<basic_printf_context<type_identity_t<Char>>> args)
     -> std::basic_string<Char> {
   auto buf = basic_memory_buffer<Char>();
   detail::vprintf(buf, fmt, args);
@@ -612,10 +615,8 @@ inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
 }
 
 template <typename Char>
-inline auto vfprintf(
+inline auto vfprintf(std::FILE* f, basic_string_view<Char> fmt,
-    std::FILE* f, basic_string_view<Char> fmt,
+                     typename vprintf_args<Char>::type args) -> int {
-    basic_format_args<basic_printf_context<type_identity_t<Char>>> args)
-    -> int {
   auto buf = basic_memory_buffer<Char>();
   detail::vprintf(buf, fmt, args);
   size_t size = buf.size();
@@ -640,9 +641,8 @@ inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
 }
 
 template <typename Char>
-FMT_DEPRECATED inline auto vprintf(
+FMT_DEPRECATED inline auto vprintf(basic_string_view<Char> fmt,
-    basic_string_view<Char> fmt,
+                                   typename vprintf_args<Char>::type args)
-    basic_format_args<basic_printf_context<type_identity_t<Char>>> args)
     -> int {
   return vfprintf(stdout, fmt, args);
 }

include/fmt/xchar.h

@@ -128,7 +128,7 @@ auto join(const std::tuple<T...>& 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> format_str,
-             basic_format_args<buffer_context<type_identity_t<Char>>> args)
+             typename detail::vformat_args<Char>::type args)
     -> std::basic_string<Char> {
   auto buf = basic_memory_buffer<Char>();
   detail::vformat_to(buf, format_str, args);
@@ -155,9 +155,8 @@ template <typename Locale, typename S,
           typename Char = detail::format_string_char_t<S>,
           FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
                             detail::is_exotic_char<Char>::value)>
-inline auto vformat(
+inline auto vformat(const Locale& loc, const S& format_str,
-    const Locale& loc, const S& format_str,
+                    typename detail::vformat_args<Char>::type args)
-    basic_format_args<buffer_context<type_identity_t<Char>>> args)
     -> std::basic_string<Char> {
   return detail::vformat(loc, detail::to_string_view(format_str), args);
 }
@@ -177,8 +176,7 @@ 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& format_str,
-                basic_format_args<buffer_context<type_identity_t<Char>>> args)
+                typename detail::vformat_args<Char>::type args) -> OutputIt {
-    -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
   detail::vformat_to(buf, detail::to_string_view(format_str), args);
   return detail::get_iterator(buf, out);
@@ -198,9 +196,9 @@ template <typename Locale, typename S, typename OutputIt, typename... Args,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
                             detail::is_locale<Locale>::value&&
                                 detail::is_exotic_char<Char>::value)>
-inline auto vformat_to(
+inline auto vformat_to(OutputIt out, const Locale& loc, const S& format_str,
-    OutputIt out, const Locale& loc, const S& format_str,
+                       typename detail::vformat_args<Char>::type args)
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) -> OutputIt {
+    -> OutputIt {
   auto&& buf = detail::get_buffer<Char>(out);
   vformat_to(buf, detail::to_string_view(format_str), args,
              detail::locale_ref(loc));
@@ -222,9 +220,9 @@ inline auto format_to(OutputIt out, const Locale& loc, const S& format_str,
 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(
+inline auto vformat_to_n(OutputIt out, size_t n,
-    OutputIt out, size_t n, basic_string_view<Char> format_str,
+                         basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+                         typename detail::vformat_args<Char>::type args)
     -> format_to_n_result<OutputIt> {
   using traits = detail::fixed_buffer_traits;
   auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);