X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fvendor%2Ffmt%2Fcore.h;h=bed8b40d3ee5513529d22c887c5bdf35121c3e97;hb=8b75cd779ffe332281fec189cdf808e4ee452572;hp=92a7aa1df69ba84553c987c591a1bac1ec187c88;hpb=dc65dda314fcd676fabfe73942c34cb93b7fea40;p=lttng-tools.git

diff --git a/src/vendor/fmt/core.h b/src/vendor/fmt/core.h
index 92a7aa1df..bed8b40d3 100644
--- a/src/vendor/fmt/core.h
+++ b/src/vendor/fmt/core.h
@@ -10,14 +10,14 @@
 
 #include <cstddef>  // std::byte
 #include <cstdio>   // std::FILE
-#include <cstring>
+#include <cstring>  // std::strlen
 #include <iterator>
 #include <limits>
 #include <string>
 #include <type_traits>
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
-#define FMT_VERSION 80101
+#define FMT_VERSION 90100
 
 #if defined(__clang__) && !defined(__ibmxl__)
 #  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
@@ -49,29 +49,29 @@
 #  define FMT_ICC_VERSION 0
 #endif
 
-#ifdef __NVCC__
-#  define FMT_NVCC __NVCC__
-#else
-#  define FMT_NVCC 0
-#endif
-
 #ifdef _MSC_VER
-#  define FMT_MSC_VER _MSC_VER
+#  define FMT_MSC_VERSION _MSC_VER
 #  define FMT_MSC_WARNING(...) __pragma(warning(__VA_ARGS__))
 #else
-#  define FMT_MSC_VER 0
+#  define FMT_MSC_VERSION 0
 #  define FMT_MSC_WARNING(...)
 #endif
 
+#ifdef _MSVC_LANG
+#  define FMT_CPLUSPLUS _MSVC_LANG
+#else
+#  define FMT_CPLUSPLUS __cplusplus
+#endif
+
 #ifdef __has_feature
 #  define FMT_HAS_FEATURE(x) __has_feature(x)
 #else
 #  define FMT_HAS_FEATURE(x) 0
 #endif
 
-#if defined(__has_include) &&                             \
-    (!defined(__INTELLISENSE__) || FMT_MSC_VER > 1900) && \
-    (!FMT_ICC_VERSION || FMT_ICC_VERSION >= 1600)
+#if (defined(__has_include) || FMT_ICC_VERSION >= 1600 || \
+     FMT_MSC_VERSION > 1900) &&                           \
+    !defined(__INTELLISENSE__)
 #  define FMT_HAS_INCLUDE(x) __has_include(x)
 #else
 #  define FMT_HAS_INCLUDE(x) 0
@@ -83,12 +83,6 @@
 #  define FMT_HAS_CPP_ATTRIBUTE(x) 0
 #endif
 
-#ifdef _MSVC_LANG
-#  define FMT_CPLUSPLUS _MSVC_LANG
-#else
-#  define FMT_CPLUSPLUS __cplusplus
-#endif
-
 #define FMT_HAS_CPP14_ATTRIBUTE(attribute) \
   (FMT_CPLUSPLUS >= 201402L && FMT_HAS_CPP_ATTRIBUTE(attribute))
 
@@ -98,37 +92,38 @@
 // Check if relaxed C++14 constexpr is supported.
 // GCC doesn't allow throw in constexpr until version 6 (bug 67371).
 #ifndef FMT_USE_CONSTEXPR
-#  define FMT_USE_CONSTEXPR                                           \
-    (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VER >= 1912 || \
-     (FMT_GCC_VERSION >= 600 && __cplusplus >= 201402L)) &&           \
-        !FMT_NVCC && !FMT_ICC_VERSION
+#  if (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VERSION >= 1912 || \
+       (FMT_GCC_VERSION >= 600 && FMT_CPLUSPLUS >= 201402L)) &&             \
+      !FMT_ICC_VERSION && !defined(__NVCC__)
+#    define FMT_USE_CONSTEXPR 1
+#  else
+#    define FMT_USE_CONSTEXPR 0
+#  endif
 #endif
 #if FMT_USE_CONSTEXPR
 #  define FMT_CONSTEXPR constexpr
-#  define FMT_CONSTEXPR_DECL constexpr
 #else
 #  define FMT_CONSTEXPR
-#  define FMT_CONSTEXPR_DECL
 #endif
 
-#if ((__cplusplus >= 202002L) &&                              \
+#if ((FMT_CPLUSPLUS >= 202002L) &&                            \
      (!defined(_GLIBCXX_RELEASE) || _GLIBCXX_RELEASE > 9)) || \
-    (__cplusplus >= 201709L && FMT_GCC_VERSION >= 1002)
+    (FMT_CPLUSPLUS >= 201709L && FMT_GCC_VERSION >= 1002)
 #  define FMT_CONSTEXPR20 constexpr
 #else
 #  define FMT_CONSTEXPR20
 #endif
 
-// Check if constexpr std::char_traits<>::compare,length is supported.
+// Check if constexpr std::char_traits<>::{compare,length} are supported.
 #if defined(__GLIBCXX__)
-#  if __cplusplus >= 201703L && defined(_GLIBCXX_RELEASE) && \
+#  if FMT_CPLUSPLUS >= 201703L && defined(_GLIBCXX_RELEASE) && \
       _GLIBCXX_RELEASE >= 7  // GCC 7+ libstdc++ has _GLIBCXX_RELEASE.
 #    define FMT_CONSTEXPR_CHAR_TRAITS constexpr
 #  endif
-#elif defined(_LIBCPP_VERSION) && __cplusplus >= 201703L && \
+#elif defined(_LIBCPP_VERSION) && FMT_CPLUSPLUS >= 201703L && \
     _LIBCPP_VERSION >= 4000
 #  define FMT_CONSTEXPR_CHAR_TRAITS constexpr
-#elif FMT_MSC_VER >= 1914 && _MSVC_LANG >= 201703L
+#elif FMT_MSC_VERSION >= 1914 && FMT_CPLUSPLUS >= 201703L
 #  define FMT_CONSTEXPR_CHAR_TRAITS constexpr
 #endif
 #ifndef FMT_CONSTEXPR_CHAR_TRAITS
@@ -138,57 +133,43 @@
 // Check if exceptions are disabled.
 #ifndef FMT_EXCEPTIONS
 #  if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || \
-      FMT_MSC_VER && !_HAS_EXCEPTIONS
+      (FMT_MSC_VERSION && !_HAS_EXCEPTIONS)
 #    define FMT_EXCEPTIONS 0
 #  else
 #    define FMT_EXCEPTIONS 1
 #  endif
 #endif
 
-// Define FMT_USE_NOEXCEPT to make fmt use noexcept (C++11 feature).
-#ifndef FMT_USE_NOEXCEPT
-#  define FMT_USE_NOEXCEPT 0
-#endif
-
-#if FMT_USE_NOEXCEPT || FMT_HAS_FEATURE(cxx_noexcept) || \
-    FMT_GCC_VERSION >= 408 || FMT_MSC_VER >= 1900
-#  define FMT_DETECTED_NOEXCEPT noexcept
-#  define FMT_HAS_CXX11_NOEXCEPT 1
-#else
-#  define FMT_DETECTED_NOEXCEPT throw()
-#  define FMT_HAS_CXX11_NOEXCEPT 0
-#endif
-
-#ifndef FMT_NOEXCEPT
-#  if FMT_EXCEPTIONS || FMT_HAS_CXX11_NOEXCEPT
-#    define FMT_NOEXCEPT FMT_DETECTED_NOEXCEPT
+#ifndef FMT_DEPRECATED
+#  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VERSION >= 1900
+#    define FMT_DEPRECATED [[deprecated]]
 #  else
-#    define FMT_NOEXCEPT
+#    if (defined(__GNUC__) && !defined(__LCC__)) || defined(__clang__)
+#      define FMT_DEPRECATED __attribute__((deprecated))
+#    elif FMT_MSC_VERSION
+#      define FMT_DEPRECATED __declspec(deprecated)
+#    else
+#      define FMT_DEPRECATED /* deprecated */
+#    endif
 #  endif
 #endif
 
 // [[noreturn]] is disabled on MSVC and NVCC because of bogus unreachable code
 // warnings.
-#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VER && \
-    !FMT_NVCC
+#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VERSION && \
+    !defined(__NVCC__)
 #  define FMT_NORETURN [[noreturn]]
 #else
 #  define FMT_NORETURN
 #endif
 
-#if __cplusplus == 201103L || __cplusplus == 201402L
-#  if defined(__INTEL_COMPILER) || defined(__PGI)
-#    define FMT_FALLTHROUGH
-#  elif defined(__clang__)
-#    define FMT_FALLTHROUGH [[clang::fallthrough]]
-#  elif FMT_GCC_VERSION >= 700 && \
-      (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 520)
-#    define FMT_FALLTHROUGH [[gnu::fallthrough]]
-#  else
-#    define FMT_FALLTHROUGH
-#  endif
-#elif FMT_HAS_CPP17_ATTRIBUTE(fallthrough)
+#if FMT_HAS_CPP17_ATTRIBUTE(fallthrough)
 #  define FMT_FALLTHROUGH [[fallthrough]]
+#elif defined(__clang__)
+#  define FMT_FALLTHROUGH [[clang::fallthrough]]
+#elif FMT_GCC_VERSION >= 700 && \
+    (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 520)
+#  define FMT_FALLTHROUGH [[gnu::fallthrough]]
 #else
 #  define FMT_FALLTHROUGH
 #endif
@@ -219,24 +200,20 @@
 #  endif
 #endif
 
-#ifndef FMT_DEPRECATED
-#  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VER >= 1900
-#    define FMT_DEPRECATED [[deprecated]]
-#  else
-#    if (defined(__GNUC__) && !defined(__LCC__)) || defined(__clang__)
-#      define FMT_DEPRECATED __attribute__((deprecated))
-#    elif FMT_MSC_VER
-#      define FMT_DEPRECATED __declspec(deprecated)
-#    else
-#      define FMT_DEPRECATED /* deprecated */
-#    endif
-#  endif
+// An inline std::forward replacement.
+#define FMT_FORWARD(...) static_cast<decltype(__VA_ARGS__)&&>(__VA_ARGS__)
+
+#ifdef _MSC_VER
+#  define FMT_UNCHECKED_ITERATOR(It) \
+    using _Unchecked_type = It  // Mark iterator as checked.
+#else
+#  define FMT_UNCHECKED_ITERATOR(It) using unchecked_type = It
 #endif
 
 #ifndef FMT_BEGIN_NAMESPACE
 #  define FMT_BEGIN_NAMESPACE \
     namespace fmt {           \
-    inline namespace v8 {
+    inline namespace v9 {
 #  define FMT_END_NAMESPACE \
     }                       \
     }
@@ -270,25 +247,24 @@
 #endif
 
 // libc++ supports string_view in pre-c++17.
-#if (FMT_HAS_INCLUDE(<string_view>) &&                       \
-     (__cplusplus > 201402L || defined(_LIBCPP_VERSION))) || \
-    (defined(_MSVC_LANG) && _MSVC_LANG > 201402L && _MSC_VER >= 1910)
+#if FMT_HAS_INCLUDE(<string_view>) && \
+    (FMT_CPLUSPLUS >= 201703L || defined(_LIBCPP_VERSION))
 #  include <string_view>
 #  define FMT_USE_STRING_VIEW
-#elif FMT_HAS_INCLUDE("experimental/string_view") && __cplusplus >= 201402L
+#elif FMT_HAS_INCLUDE("experimental/string_view") && FMT_CPLUSPLUS >= 201402L
 #  include <experimental/string_view>
 #  define FMT_USE_EXPERIMENTAL_STRING_VIEW
 #endif
 
 #ifndef FMT_UNICODE
-#  define FMT_UNICODE !FMT_MSC_VER
+#  define FMT_UNICODE !FMT_MSC_VERSION
 #endif
 
 #ifndef FMT_CONSTEVAL
-#  if ((FMT_GCC_VERSION >= 1000 || FMT_CLANG_VERSION >= 1101) &&      \
-       __cplusplus > 201703L && !defined(__apple_build_version__)) || \
-      (defined(__cpp_consteval) &&                                    \
-       (!FMT_MSC_VER || _MSC_FULL_VER >= 193030704))
+#  if ((FMT_GCC_VERSION >= 1000 || FMT_CLANG_VERSION >= 1101) &&         \
+       FMT_CPLUSPLUS >= 202002L && !defined(__apple_build_version__)) || \
+      (defined(__cpp_consteval) &&                                       \
+       (!FMT_MSC_VERSION || _MSC_FULL_VER >= 193030704))
 // consteval is broken in MSVC before VS2022 and Apple clang 13.
 #    define FMT_CONSTEVAL consteval
 #    define FMT_HAS_CONSTEVAL
@@ -297,19 +273,20 @@
 #  endif
 #endif
 
-#ifndef FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
-#  if defined(__cpp_nontype_template_args) &&                \
-      ((FMT_GCC_VERSION >= 903 && __cplusplus >= 201709L) || \
-       __cpp_nontype_template_args >= 201911L)
-#    define FMT_USE_NONTYPE_TEMPLATE_PARAMETERS 1
+#ifndef FMT_USE_NONTYPE_TEMPLATE_ARGS
+#  if defined(__cpp_nontype_template_args) &&                  \
+      ((FMT_GCC_VERSION >= 903 && FMT_CPLUSPLUS >= 201709L) || \
+       __cpp_nontype_template_args >= 201911L) &&              \
+      !defined(__NVCOMPILER)
+#    define FMT_USE_NONTYPE_TEMPLATE_ARGS 1
 #  else
-#    define FMT_USE_NONTYPE_TEMPLATE_PARAMETERS 0
+#    define FMT_USE_NONTYPE_TEMPLATE_ARGS 0
 #  endif
 #endif
 
 // Enable minimal optimizations for more compact code in debug mode.
 FMT_GCC_PRAGMA("GCC push_options")
-#ifndef __OPTIMIZE__
+#if !defined(__OPTIMIZE__) && !defined(__NVCOMPILER)
 FMT_GCC_PRAGMA("GCC optimize(\"Og\")")
 #endif
 
@@ -330,6 +307,20 @@ template <typename T>
 using remove_cvref_t = typename std::remove_cv<remove_reference_t<T>>::type;
 template <typename T> struct type_identity { using type = T; };
 template <typename T> using type_identity_t = typename type_identity<T>::type;
+template <typename T>
+using underlying_t = typename std::underlying_type<T>::type;
+
+template <typename...> struct disjunction : std::false_type {};
+template <typename P> struct disjunction<P> : P {};
+template <typename P1, typename... Pn>
+struct disjunction<P1, Pn...>
+    : conditional_t<bool(P1::value), P1, disjunction<Pn...>> {};
+
+template <typename...> struct conjunction : std::true_type {};
+template <typename P> struct conjunction<P> : P {};
+template <typename P1, typename... Pn>
+struct conjunction<P1, Pn...>
+    : conditional_t<bool(P1::value), conjunction<Pn...>, P1> {};
 
 struct monostate {
   constexpr monostate() {}
@@ -346,13 +337,13 @@ struct monostate {
 
 FMT_BEGIN_DETAIL_NAMESPACE
 
-// Suppress "unused variable" warnings with the method described in
+// Suppresses "unused variable" warnings with the method described in
 // https://herbsutter.com/2009/10/18/mailbag-shutting-up-compiler-warnings/.
 // (void)var does not work on many Intel compilers.
 template <typename... T> FMT_CONSTEXPR void ignore_unused(const T&...) {}
 
-constexpr FMT_INLINE auto is_constant_evaluated(bool default_value = false)
-    FMT_NOEXCEPT -> bool {
+constexpr FMT_INLINE auto is_constant_evaluated(
+    bool default_value = false) noexcept -> bool {
 #ifdef __cpp_lib_is_constant_evaluated
   ignore_unused(default_value);
   return std::is_constant_evaluated();
@@ -361,7 +352,7 @@ constexpr FMT_INLINE auto is_constant_evaluated(bool default_value = false)
 #endif
 }
 
-// A function to suppress "conditional expression is constant" warnings.
+// Suppresses "conditional expression is constant" warnings.
 template <typename T> constexpr FMT_INLINE auto const_check(T value) -> T {
   return value;
 }
@@ -371,7 +362,7 @@ FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
 
 #ifndef FMT_ASSERT
 #  ifdef NDEBUG
-// FMT_ASSERT is not empty to avoid -Werror=empty-body.
+// FMT_ASSERT is not empty to avoid -Wempty-body.
 #    define FMT_ASSERT(condition, message) \
       ::fmt::detail::ignore_unused((condition), (message))
 #  else
@@ -382,12 +373,6 @@ FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
 #  endif
 #endif
 
-#ifdef __cpp_lib_byte
-using byte = std::byte;
-#else
-enum class byte : unsigned char {};
-#endif
-
 #if defined(FMT_USE_STRING_VIEW)
 template <typename Char> using std_string_view = std::basic_string_view<Char>;
 #elif defined(FMT_USE_EXPERIMENTAL_STRING_VIEW)
@@ -399,11 +384,11 @@ template <typename T> struct std_string_view {};
 
 #ifdef FMT_USE_INT128
 // Do nothing.
-#elif defined(__SIZEOF_INT128__) && !FMT_NVCC && \
-    !(FMT_CLANG_VERSION && FMT_MSC_VER)
+#elif defined(__SIZEOF_INT128__) && !defined(__NVCC__) && \
+    !(FMT_CLANG_VERSION && FMT_MSC_VERSION)
 #  define FMT_USE_INT128 1
-using int128_t = __int128_t;
-using uint128_t = __uint128_t;
+using int128_opt = __int128_t;  // An optional native 128-bit integer.
+using uint128_opt = __uint128_t;
 template <typename T> inline auto convert_for_visit(T value) -> T {
   return value;
 }
@@ -411,27 +396,24 @@ template <typename T> inline auto convert_for_visit(T value) -> T {
 #  define FMT_USE_INT128 0
 #endif
 #if !FMT_USE_INT128
-enum class int128_t {};
-enum class uint128_t {};
+enum class int128_opt {};
+enum class uint128_opt {};
 // Reduce template instantiations.
-template <typename T> inline auto convert_for_visit(T) -> monostate {
-  return {};
-}
+template <typename T> auto convert_for_visit(T) -> monostate { return {}; }
 #endif
 
 // Casts a nonnegative integer to unsigned.
 template <typename Int>
 FMT_CONSTEXPR auto to_unsigned(Int value) ->
     typename std::make_unsigned<Int>::type {
-  FMT_ASSERT(value >= 0, "negative value");
+  FMT_ASSERT(std::is_unsigned<Int>::value || value >= 0, "negative value");
   return static_cast<typename std::make_unsigned<Int>::type>(value);
 }
 
 FMT_MSC_WARNING(suppress : 4566) constexpr unsigned char micro[] = "\u00B5";
 
 constexpr auto is_utf8() -> bool {
-  // Avoid buggy sign extensions in MSVC's constant evaluation mode.
-  // https://developercommunity.visualstudio.com/t/C-difference-in-behavior-for-unsigned/1233612
+  // Avoid buggy sign extensions in MSVC's constant evaluation mode (#2297).
   using uchar = unsigned char;
   return FMT_UNICODE || (sizeof(micro) == 3 && uchar(micro[0]) == 0xC2 &&
                          uchar(micro[1]) == 0xB5);
@@ -454,12 +436,11 @@ template <typename Char> class basic_string_view {
   using value_type = Char;
   using iterator = const Char*;
 
-  constexpr basic_string_view() FMT_NOEXCEPT : data_(nullptr), size_(0) {}
+  constexpr basic_string_view() noexcept : data_(nullptr), size_(0) {}
 
   /** Constructs a string reference object from a C string and a size. */
-  constexpr basic_string_view(const Char* s, size_t count) FMT_NOEXCEPT
-      : data_(s),
-        size_(count) {}
+  constexpr basic_string_view(const Char* s, size_t count) noexcept
+      : data_(s), size_(count) {}
 
   /**
     \rst
@@ -479,29 +460,28 @@ template <typename Char> class basic_string_view {
   /** Constructs a string reference from a ``std::basic_string`` object. */
   template <typename Traits, typename Alloc>
   FMT_CONSTEXPR basic_string_view(
-      const std::basic_string<Char, Traits, Alloc>& s) FMT_NOEXCEPT
-      : data_(s.data()),
-        size_(s.size()) {}
+      const std::basic_string<Char, Traits, Alloc>& s) noexcept
+      : data_(s.data()), size_(s.size()) {}
 
   template <typename S, FMT_ENABLE_IF(std::is_same<
                                       S, detail::std_string_view<Char>>::value)>
-  FMT_CONSTEXPR basic_string_view(S s) FMT_NOEXCEPT : data_(s.data()),
-                                                      size_(s.size()) {}
+  FMT_CONSTEXPR basic_string_view(S s) noexcept
+      : data_(s.data()), size_(s.size()) {}
 
   /** Returns a pointer to the string data. */
-  constexpr auto data() const FMT_NOEXCEPT -> const Char* { return data_; }
+  constexpr auto data() const noexcept -> const Char* { return data_; }
 
   /** Returns the string size. */
-  constexpr auto size() const FMT_NOEXCEPT -> size_t { return size_; }
+  constexpr auto size() const noexcept -> size_t { return size_; }
 
-  constexpr auto begin() const FMT_NOEXCEPT -> iterator { return data_; }
-  constexpr auto end() const FMT_NOEXCEPT -> iterator { return data_ + size_; }
+  constexpr auto begin() const noexcept -> iterator { return data_; }
+  constexpr auto end() const noexcept -> iterator { return data_ + size_; }
 
-  constexpr auto operator[](size_t pos) const FMT_NOEXCEPT -> const Char& {
+  constexpr auto operator[](size_t pos) const noexcept -> const Char& {
     return data_[pos];
   }
 
-  FMT_CONSTEXPR void remove_prefix(size_t n) FMT_NOEXCEPT {
+  FMT_CONSTEXPR void remove_prefix(size_t n) noexcept {
     data_ += n;
     size_ -= n;
   }
@@ -543,6 +523,14 @@ using string_view = basic_string_view<char>;
 template <typename T> struct is_char : std::false_type {};
 template <> struct is_char<char> : std::true_type {};
 
+FMT_BEGIN_DETAIL_NAMESPACE
+
+// A base class for compile-time strings.
+struct compile_string {};
+
+template <typename S>
+struct is_compile_string : std::is_base_of<compile_string, S> {};
+
 // Returns a string view of `s`.
 template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
 FMT_INLINE auto to_string_view(const Char* s) -> basic_string_view<Char> {
@@ -559,33 +547,21 @@ constexpr auto to_string_view(basic_string_view<Char> s)
   return s;
 }
 template <typename Char,
-          FMT_ENABLE_IF(!std::is_empty<detail::std_string_view<Char>>::value)>
-inline auto to_string_view(detail::std_string_view<Char> s)
-    -> basic_string_view<Char> {
+          FMT_ENABLE_IF(!std::is_empty<std_string_view<Char>>::value)>
+inline auto to_string_view(std_string_view<Char> s) -> basic_string_view<Char> {
   return s;
 }
-
-// A base class for compile-time strings. It is defined in the fmt namespace to
-// make formatting functions visible via ADL, e.g. format(FMT_STRING("{}"), 42).
-struct compile_string {};
-
-template <typename S>
-struct is_compile_string : std::is_base_of<compile_string, S> {};
-
 template <typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
 constexpr auto to_string_view(const S& s)
     -> basic_string_view<typename S::char_type> {
   return basic_string_view<typename S::char_type>(s);
 }
-
-FMT_BEGIN_DETAIL_NAMESPACE
-
 void to_string_view(...);
-using fmt::to_string_view;
 
 // Specifies whether S is a string type convertible to fmt::basic_string_view.
 // It should be a constexpr function but MSVC 2017 fails to compile it in
 // enable_if and MSVC 2015 fails to compile it as an alias template.
+// ADL invocation of to_string_view is DEPRECATED!
 template <typename S>
 struct is_string : std::is_class<decltype(to_string_view(std::declval<S>()))> {
 };
@@ -596,17 +572,60 @@ template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
   using type = typename result::value_type;
 };
 
-// Reports a compile-time error if S is not a valid format string.
-template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
-FMT_INLINE void check_format_string(const S&) {
-#ifdef FMT_ENFORCE_COMPILE_STRING
-  static_assert(is_compile_string<S>::value,
-                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
-                "FMT_STRING.");
-#endif
+enum class type {
+  none_type,
+  // Integer types should go first,
+  int_type,
+  uint_type,
+  long_long_type,
+  ulong_long_type,
+  int128_type,
+  uint128_type,
+  bool_type,
+  char_type,
+  last_integer_type = char_type,
+  // followed by floating-point types.
+  float_type,
+  double_type,
+  long_double_type,
+  last_numeric_type = long_double_type,
+  cstring_type,
+  string_type,
+  pointer_type,
+  custom_type
+};
+
+// Maps core type T to the corresponding type enum constant.
+template <typename T, typename Char>
+struct type_constant : std::integral_constant<type, type::custom_type> {};
+
+#define FMT_TYPE_CONSTANT(Type, constant) \
+  template <typename Char>                \
+  struct type_constant<Type, Char>        \
+      : std::integral_constant<type, type::constant> {}
+
+FMT_TYPE_CONSTANT(int, int_type);
+FMT_TYPE_CONSTANT(unsigned, uint_type);
+FMT_TYPE_CONSTANT(long long, long_long_type);
+FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
+FMT_TYPE_CONSTANT(int128_opt, int128_type);
+FMT_TYPE_CONSTANT(uint128_opt, uint128_type);
+FMT_TYPE_CONSTANT(bool, bool_type);
+FMT_TYPE_CONSTANT(Char, char_type);
+FMT_TYPE_CONSTANT(float, float_type);
+FMT_TYPE_CONSTANT(double, double_type);
+FMT_TYPE_CONSTANT(long double, long_double_type);
+FMT_TYPE_CONSTANT(const Char*, cstring_type);
+FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
+FMT_TYPE_CONSTANT(const void*, pointer_type);
+
+constexpr bool is_integral_type(type t) {
+  return t > type::none_type && t <= type::last_integer_type;
+}
+
+constexpr bool is_arithmetic_type(type t) {
+  return t > type::none_type && t <= type::last_numeric_type;
 }
-template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
-void check_format_string(S);
 
 FMT_NORETURN FMT_API void throw_format_error(const char* message);
 
@@ -615,7 +634,9 @@ struct error_handler {
   constexpr error_handler(const error_handler&) = default;
 
   // This function is intentionally not constexpr to give a compile-time error.
-  FMT_NORETURN FMT_API void on_error(const char* message);
+  FMT_NORETURN void on_error(const char* message) {
+    throw_format_error(message);
+  }
 };
 FMT_END_DETAIL_NAMESPACE
 
@@ -635,6 +656,8 @@ class basic_format_parse_context : private ErrorHandler {
   basic_string_view<Char> format_str_;
   int next_arg_id_;
 
+  FMT_CONSTEXPR void do_check_arg_id(int id);
+
  public:
   using char_type = Char;
   using iterator = typename basic_string_view<Char>::iterator;
@@ -648,16 +671,14 @@ class basic_format_parse_context : private ErrorHandler {
     Returns an iterator to the beginning of the format string range being
     parsed.
    */
-  constexpr auto begin() const FMT_NOEXCEPT -> iterator {
+  constexpr auto begin() const noexcept -> iterator {
     return format_str_.begin();
   }
 
   /**
     Returns an iterator past the end of the format string range being parsed.
    */
-  constexpr auto end() const FMT_NOEXCEPT -> iterator {
-    return format_str_.end();
-  }
+  constexpr auto end() const noexcept -> iterator { return format_str_.end(); }
 
   /** Advances the begin iterator to ``it``. */
   FMT_CONSTEXPR void advance_to(iterator it) {
@@ -669,25 +690,29 @@ class basic_format_parse_context : private ErrorHandler {
     the next argument index and switches to the automatic indexing.
    */
   FMT_CONSTEXPR auto next_arg_id() -> int {
-    // Don't check if the argument id is valid to avoid overhead and because it
-    // will be checked during formatting anyway.
-    if (next_arg_id_ >= 0) return next_arg_id_++;
-    on_error("cannot switch from manual to automatic argument indexing");
-    return 0;
+    if (next_arg_id_ < 0) {
+      on_error("cannot switch from manual to automatic argument indexing");
+      return 0;
+    }
+    int id = next_arg_id_++;
+    do_check_arg_id(id);
+    return id;
   }
 
   /**
     Reports an error if using the automatic argument indexing; otherwise
     switches to the manual indexing.
    */
-  FMT_CONSTEXPR void check_arg_id(int) {
-    if (next_arg_id_ > 0)
+  FMT_CONSTEXPR void check_arg_id(int id) {
+    if (next_arg_id_ > 0) {
       on_error("cannot switch from automatic to manual argument indexing");
-    else
-      next_arg_id_ = -1;
+      return;
+    }
+    next_arg_id_ = -1;
+    do_check_arg_id(id);
   }
-
   FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {}
+  FMT_CONSTEXPR void check_dynamic_spec(int arg_id);
 
   FMT_CONSTEXPR void on_error(const char* message) {
     ErrorHandler::on_error(message);
@@ -698,6 +723,65 @@ class basic_format_parse_context : private ErrorHandler {
 
 using format_parse_context = basic_format_parse_context<char>;
 
+FMT_BEGIN_DETAIL_NAMESPACE
+// A parse context with extra data used only in compile-time checks.
+template <typename Char, typename ErrorHandler = detail::error_handler>
+class compile_parse_context
+    : public basic_format_parse_context<Char, ErrorHandler> {
+ private:
+  int num_args_;
+  const type* types_;
+  using base = basic_format_parse_context<Char, ErrorHandler>;
+
+ public:
+  explicit FMT_CONSTEXPR compile_parse_context(
+      basic_string_view<Char> format_str, int num_args, const type* types,
+      ErrorHandler eh = {}, int next_arg_id = 0)
+      : base(format_str, eh, next_arg_id), num_args_(num_args), types_(types) {}
+
+  constexpr auto num_args() const -> int { return num_args_; }
+  constexpr auto arg_type(int id) const -> type { return types_[id]; }
+
+  FMT_CONSTEXPR auto next_arg_id() -> int {
+    int id = base::next_arg_id();
+    if (id >= num_args_) this->on_error("argument not found");
+    return id;
+  }
+
+  FMT_CONSTEXPR void check_arg_id(int id) {
+    base::check_arg_id(id);
+    if (id >= num_args_) this->on_error("argument not found");
+  }
+  using base::check_arg_id;
+
+  FMT_CONSTEXPR void check_dynamic_spec(int arg_id) {
+    if (arg_id < num_args_ && types_ && !is_integral_type(types_[arg_id]))
+      this->on_error("width/precision is not integer");
+  }
+};
+FMT_END_DETAIL_NAMESPACE
+
+template <typename Char, typename ErrorHandler>
+FMT_CONSTEXPR void
+basic_format_parse_context<Char, ErrorHandler>::do_check_arg_id(int id) {
+  // Argument id is only checked at compile-time during parsing because
+  // formatting has its own validation.
+  if (detail::is_constant_evaluated() && FMT_GCC_VERSION >= 1200) {
+    using context = detail::compile_parse_context<Char, ErrorHandler>;
+    if (id >= static_cast<context*>(this)->num_args())
+      on_error("argument not found");
+  }
+}
+
+template <typename Char, typename ErrorHandler>
+FMT_CONSTEXPR void
+basic_format_parse_context<Char, ErrorHandler>::check_dynamic_spec(int arg_id) {
+  if (detail::is_constant_evaluated()) {
+    using context = detail::compile_parse_context<Char, ErrorHandler>;
+    static_cast<context*>(this)->check_dynamic_spec(arg_id);
+  }
+}
+
 template <typename Context> class basic_format_arg;
 template <typename Context> class basic_format_args;
 template <typename Context> class dynamic_format_arg_store;
@@ -744,10 +828,10 @@ constexpr auto has_const_formatter() -> bool {
 template <typename Container>
 inline auto get_container(std::back_insert_iterator<Container> it)
     -> Container& {
-  using bi_iterator = std::back_insert_iterator<Container>;
-  struct accessor : bi_iterator {
-    accessor(bi_iterator iter) : bi_iterator(iter) {}
-    using bi_iterator::container;
+  using base = std::back_insert_iterator<Container>;
+  struct accessor : base {
+    accessor(base b) : base(b) {}
+    using base::container;
   };
   return *accessor(it).container;
 }
@@ -784,18 +868,16 @@ template <typename T> class buffer {
  protected:
   // Don't initialize ptr_ since it is not accessed to save a few cycles.
   FMT_MSC_WARNING(suppress : 26495)
-  buffer(size_t sz) FMT_NOEXCEPT : size_(sz), capacity_(sz) {}
+  buffer(size_t sz) noexcept : size_(sz), capacity_(sz) {}
 
-  FMT_CONSTEXPR20 buffer(T* p = nullptr, size_t sz = 0,
-                         size_t cap = 0) FMT_NOEXCEPT : ptr_(p),
-                                                        size_(sz),
-                                                        capacity_(cap) {}
+  FMT_CONSTEXPR20 buffer(T* p = nullptr, size_t sz = 0, size_t cap = 0) noexcept
+      : ptr_(p), size_(sz), capacity_(cap) {}
 
   FMT_CONSTEXPR20 ~buffer() = default;
   buffer(buffer&&) = default;
 
   /** Sets the buffer data and capacity. */
-  FMT_CONSTEXPR void set(T* buf_data, size_t buf_capacity) FMT_NOEXCEPT {
+  FMT_CONSTEXPR void set(T* buf_data, size_t buf_capacity) noexcept {
     ptr_ = buf_data;
     capacity_ = buf_capacity;
   }
@@ -810,23 +892,23 @@ template <typename T> class buffer {
   buffer(const buffer&) = delete;
   void operator=(const buffer&) = delete;
 
-  auto begin() FMT_NOEXCEPT -> T* { return ptr_; }
-  auto end() FMT_NOEXCEPT -> T* { return ptr_ + size_; }
+  auto begin() noexcept -> T* { return ptr_; }
+  auto end() noexcept -> T* { return ptr_ + size_; }
 
-  auto begin() const FMT_NOEXCEPT -> const T* { return ptr_; }
-  auto end() const FMT_NOEXCEPT -> const T* { return ptr_ + size_; }
+  auto begin() const noexcept -> const T* { return ptr_; }
+  auto end() const noexcept -> const T* { return ptr_ + size_; }
 
   /** Returns the size of this buffer. */
-  constexpr auto size() const FMT_NOEXCEPT -> size_t { return size_; }
+  constexpr auto size() const noexcept -> size_t { return size_; }
 
   /** Returns the capacity of this buffer. */
-  constexpr auto capacity() const FMT_NOEXCEPT -> size_t { return capacity_; }
+  constexpr auto capacity() const noexcept -> size_t { return capacity_; }
 
   /** Returns a pointer to the buffer data. */
-  FMT_CONSTEXPR auto data() FMT_NOEXCEPT -> T* { return ptr_; }
+  FMT_CONSTEXPR auto data() noexcept -> T* { return ptr_; }
 
   /** Returns a pointer to the buffer data. */
-  FMT_CONSTEXPR auto data() const FMT_NOEXCEPT -> const T* { return ptr_; }
+  FMT_CONSTEXPR auto data() const noexcept -> const T* { return ptr_; }
 
   /** Clears this buffer. */
   void clear() { size_ = 0; }
@@ -854,11 +936,11 @@ template <typename T> class buffer {
   /** Appends data to the end of the buffer. */
   template <typename U> void append(const U* begin, const U* end);
 
-  template <typename I> FMT_CONSTEXPR auto operator[](I index) -> T& {
+  template <typename Idx> FMT_CONSTEXPR auto operator[](Idx index) -> T& {
     return ptr_[index];
   }
-  template <typename I>
-  FMT_CONSTEXPR auto operator[](I index) const -> const T& {
+  template <typename Idx>
+  FMT_CONSTEXPR auto operator[](Idx index) const -> const T& {
     return ptr_[index];
   }
 };
@@ -993,6 +1075,7 @@ class iterator_buffer<std::back_insert_iterator<Container>,
       : buffer<typename Container::value_type>(c.size()), container_(c) {}
   explicit iterator_buffer(std::back_insert_iterator<Container> out, size_t = 0)
       : iterator_buffer(get_container(out)) {}
+
   auto out() -> std::back_insert_iterator<Container> {
     return std::back_inserter(container_);
   }
@@ -1044,7 +1127,11 @@ struct fallback_formatter {
 // Specifies if T has an enabled fallback_formatter specialization.
 template <typename T, typename Char>
 using has_fallback_formatter =
+#ifdef FMT_DEPRECATED_OSTREAM
     std::is_constructible<fallback_formatter<T, Char>>;
+#else
+    std::false_type;
+#endif
 
 struct view {};
 
@@ -1128,61 +1215,6 @@ constexpr auto count_statically_named_args() -> size_t {
   return count<is_statically_named_arg<Args>::value...>();
 }
 
-enum class type {
-  none_type,
-  // Integer types should go first,
-  int_type,
-  uint_type,
-  long_long_type,
-  ulong_long_type,
-  int128_type,
-  uint128_type,
-  bool_type,
-  char_type,
-  last_integer_type = char_type,
-  // followed by floating-point types.
-  float_type,
-  double_type,
-  long_double_type,
-  last_numeric_type = long_double_type,
-  cstring_type,
-  string_type,
-  pointer_type,
-  custom_type
-};
-
-// Maps core type T to the corresponding type enum constant.
-template <typename T, typename Char>
-struct type_constant : std::integral_constant<type, type::custom_type> {};
-
-#define FMT_TYPE_CONSTANT(Type, constant) \
-  template <typename Char>                \
-  struct type_constant<Type, Char>        \
-      : std::integral_constant<type, type::constant> {}
-
-FMT_TYPE_CONSTANT(int, int_type);
-FMT_TYPE_CONSTANT(unsigned, uint_type);
-FMT_TYPE_CONSTANT(long long, long_long_type);
-FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
-FMT_TYPE_CONSTANT(int128_t, int128_type);
-FMT_TYPE_CONSTANT(uint128_t, uint128_type);
-FMT_TYPE_CONSTANT(bool, bool_type);
-FMT_TYPE_CONSTANT(Char, char_type);
-FMT_TYPE_CONSTANT(float, float_type);
-FMT_TYPE_CONSTANT(double, double_type);
-FMT_TYPE_CONSTANT(long double, long_double_type);
-FMT_TYPE_CONSTANT(const Char*, cstring_type);
-FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
-FMT_TYPE_CONSTANT(const void*, pointer_type);
-
-constexpr bool is_integral_type(type t) {
-  return t > type::none_type && t <= type::last_integer_type;
-}
-
-constexpr bool is_arithmetic_type(type t) {
-  return t > type::none_type && t <= type::last_numeric_type;
-}
-
 struct unformattable {};
 struct unformattable_char : unformattable {};
 struct unformattable_const : unformattable {};
@@ -1215,8 +1247,8 @@ template <typename Context> class value {
     unsigned uint_value;
     long long long_long_value;
     unsigned long long ulong_long_value;
-    int128_t int128_value;
-    uint128_t uint128_value;
+    int128_opt int128_value;
+    uint128_opt uint128_value;
     bool bool_value;
     char_type char_value;
     float float_value;
@@ -1233,8 +1265,8 @@ template <typename Context> class value {
   constexpr FMT_INLINE value(unsigned val) : uint_value(val) {}
   constexpr FMT_INLINE value(long long val) : long_long_value(val) {}
   constexpr FMT_INLINE value(unsigned long long val) : ulong_long_value(val) {}
-  FMT_INLINE value(int128_t val) : int128_value(val) {}
-  FMT_INLINE value(uint128_t val) : uint128_value(val) {}
+  FMT_INLINE value(int128_opt val) : int128_value(val) {}
+  FMT_INLINE value(uint128_opt val) : uint128_value(val) {}
   constexpr FMT_INLINE value(float val) : float_value(val) {}
   constexpr FMT_INLINE value(double val) : double_value(val) {}
   FMT_INLINE value(long double val) : long_double_value(val) {}
@@ -1284,7 +1316,7 @@ template <typename Context> class value {
 };
 
 template <typename Context, typename T>
-FMT_CONSTEXPR auto make_arg(const T& value) -> basic_format_arg<Context>;
+FMT_CONSTEXPR auto make_arg(T&& value) -> basic_format_arg<Context>;
 
 // To minimize the number of types we need to deal with, long is translated
 // either to int or to long long depending on its size.
@@ -1292,6 +1324,21 @@ enum { long_short = sizeof(long) == sizeof(int) };
 using long_type = conditional_t<long_short, int, long long>;
 using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;
 
+#ifdef __cpp_lib_byte
+inline auto format_as(std::byte b) -> unsigned char {
+  return static_cast<unsigned char>(b);
+}
+#endif
+
+template <typename T> struct has_format_as {
+  template <typename U, typename V = decltype(format_as(U())),
+            FMT_ENABLE_IF(std::is_enum<U>::value&& std::is_integral<V>::value)>
+  static auto check(U*) -> std::true_type;
+  static auto check(...) -> std::false_type;
+
+  enum { value = decltype(check(static_cast<T*>(nullptr)))::value };
+};
+
 // Maps formatting arguments to core types.
 // arg_mapper reports errors by returning unformattable instead of using
 // static_assert because it's used in the is_formattable trait.
@@ -1317,8 +1364,12 @@ template <typename Context> struct arg_mapper {
       -> unsigned long long {
     return val;
   }
-  FMT_CONSTEXPR FMT_INLINE auto map(int128_t val) -> int128_t { return val; }
-  FMT_CONSTEXPR FMT_INLINE auto map(uint128_t val) -> uint128_t { return val; }
+  FMT_CONSTEXPR FMT_INLINE auto map(int128_opt val) -> int128_opt {
+    return val;
+  }
+  FMT_CONSTEXPR FMT_INLINE auto map(uint128_opt val) -> uint128_opt {
+    return val;
+  }
   FMT_CONSTEXPR FMT_INLINE auto map(bool val) -> bool { return val; }
 
   template <typename T, FMT_ENABLE_IF(std::is_same<T, char>::value ||
@@ -1365,45 +1416,24 @@ template <typename Context> struct arg_mapper {
   }
   template <typename T,
             FMT_ENABLE_IF(
-                std::is_constructible<basic_string_view<char_type>, T>::value &&
+                std::is_convertible<T, basic_string_view<char_type>>::value &&
                 !is_string<T>::value && !has_formatter<T, Context>::value &&
                 !has_fallback_formatter<T, char_type>::value)>
   FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
       -> basic_string_view<char_type> {
     return basic_string_view<char_type>(val);
   }
-  template <
-      typename T,
-      FMT_ENABLE_IF(
-          std::is_constructible<std_string_view<char_type>, T>::value &&
-          !std::is_constructible<basic_string_view<char_type>, T>::value &&
-          !is_string<T>::value && !has_formatter<T, Context>::value &&
-          !has_fallback_formatter<T, char_type>::value)>
+  template <typename T,
+            FMT_ENABLE_IF(
+                std::is_convertible<T, std_string_view<char_type>>::value &&
+                !std::is_convertible<T, basic_string_view<char_type>>::value &&
+                !is_string<T>::value && !has_formatter<T, Context>::value &&
+                !has_fallback_formatter<T, char_type>::value)>
   FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
       -> basic_string_view<char_type> {
     return std_string_view<char_type>(val);
   }
 
-  using cstring_result = conditional_t<std::is_same<char_type, char>::value,
-                                       const char*, unformattable_pointer>;
-
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(const signed char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(const unsigned char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(signed char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(unsigned char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
-
   FMT_CONSTEXPR FMT_INLINE auto map(void* val) -> const void* { return val; }
   FMT_CONSTEXPR FMT_INLINE auto map(const void* val) -> const void* {
     return val;
@@ -1417,10 +1447,11 @@ template <typename Context> struct arg_mapper {
   template <
       typename T,
       FMT_ENABLE_IF(
-          std::is_member_pointer<T>::value ||
+          std::is_pointer<T>::value || std::is_member_pointer<T>::value ||
           std::is_function<typename std::remove_pointer<T>::type>::value ||
           (std::is_convertible<const T&, const void*>::value &&
-           !std::is_convertible<const T&, const char_type*>::value))>
+           !std::is_convertible<const T&, const char_type*>::value &&
+           !has_formatter<T, Context>::value))>
   FMT_CONSTEXPR auto map(const T&) -> unformattable_pointer {
     return {};
   }
@@ -1434,16 +1465,19 @@ template <typename Context> struct arg_mapper {
   template <typename T,
             FMT_ENABLE_IF(
                 std::is_enum<T>::value&& std::is_convertible<T, int>::value &&
-                !has_formatter<T, Context>::value &&
+                !has_format_as<T>::value && !has_formatter<T, Context>::value &&
                 !has_fallback_formatter<T, char_type>::value)>
-  FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
+  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
       -> decltype(std::declval<arg_mapper>().map(
-          static_cast<typename std::underlying_type<T>::type>(val))) {
-    return map(static_cast<typename std::underlying_type<T>::type>(val));
+          static_cast<underlying_t<T>>(val))) {
+    return map(static_cast<underlying_t<T>>(val));
   }
 
-  FMT_CONSTEXPR FMT_INLINE auto map(detail::byte val) -> unsigned {
-    return map(static_cast<unsigned char>(val));
+  template <typename T, FMT_ENABLE_IF(has_format_as<T>::value &&
+                                      !has_formatter<T, Context>::value)>
+  FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
+      -> decltype(std::declval<arg_mapper>().map(format_as(T()))) {
+    return map(format_as(val));
   }
 
   template <typename T, typename U = remove_cvref_t<T>>
@@ -1452,8 +1486,9 @@ template <typename Context> struct arg_mapper {
                       !std::is_const<remove_reference_t<T>>::value ||
                       has_fallback_formatter<U, char_type>::value> {};
 
-#if FMT_MSC_VER != 0 && FMT_MSC_VER < 1910
-  // Workaround a bug in MSVC.
+#if (FMT_MSC_VERSION != 0 && FMT_MSC_VERSION < 1910) || \
+    FMT_ICC_VERSION != 0 || defined(__NVCC__)
+  // Workaround a bug in MSVC and Intel (Issue 2746).
   template <typename T> FMT_CONSTEXPR FMT_INLINE auto do_map(T&& val) -> T& {
     return val;
   }
@@ -1471,6 +1506,8 @@ template <typename Context> struct arg_mapper {
   template <typename T, typename U = remove_cvref_t<T>,
             FMT_ENABLE_IF(!is_string<U>::value && !is_char<U>::value &&
                           !std::is_array<U>::value &&
+                          !std::is_pointer<U>::value &&
+                          !has_format_as<U>::value &&
                           (has_formatter<U, Context>::value ||
                            has_fallback_formatter<U, char_type>::value))>
   FMT_CONSTEXPR FMT_INLINE auto map(T&& val)
@@ -1513,12 +1550,11 @@ class appender : public std::back_insert_iterator<detail::buffer<char>> {
 
  public:
   using std::back_insert_iterator<detail::buffer<char>>::back_insert_iterator;
-  appender(base it) FMT_NOEXCEPT : base(it) {}
-  using _Unchecked_type = appender;  // Mark iterator as checked.
+  appender(base it) noexcept : base(it) {}
+  FMT_UNCHECKED_ITERATOR(appender);
 
-  auto operator++() FMT_NOEXCEPT -> appender& { return *this; }
-
-  auto operator++(int) FMT_NOEXCEPT -> appender { return *this; }
+  auto operator++() noexcept -> appender& { return *this; }
+  auto operator++(int) noexcept -> appender { return *this; }
 };
 
 // A formatting argument. It is a trivially copyable/constructible type to
@@ -1529,7 +1565,7 @@ template <typename Context> class basic_format_arg {
   detail::type type_;
 
   template <typename ContextType, typename T>
-  friend FMT_CONSTEXPR auto detail::make_arg(const T& value)
+  friend FMT_CONSTEXPR auto detail::make_arg(T&& value)
       -> basic_format_arg<ContextType>;
 
   template <typename Visitor, typename Ctx>
@@ -1564,7 +1600,7 @@ template <typename Context> class basic_format_arg {
 
   constexpr basic_format_arg() : type_(detail::type::none_type) {}
 
-  constexpr explicit operator bool() const FMT_NOEXCEPT {
+  constexpr explicit operator bool() const noexcept {
     return type_ != detail::type::none_type;
   }
 
@@ -1632,6 +1668,11 @@ auto copy_str(InputIt begin, InputIt end, appender out) -> appender {
   return out;
 }
 
+template <typename Char, typename R, typename OutputIt>
+FMT_CONSTEXPR auto copy_str(R&& rng, OutputIt out) -> OutputIt {
+  return detail::copy_str<Char>(rng.begin(), rng.end(), out);
+}
+
 #if FMT_GCC_VERSION && FMT_GCC_VERSION < 500
 // A workaround for gcc 4.8 to make void_t work in a SFINAE context.
 template <typename... Ts> struct void_t_impl { using type = void; };
@@ -1665,7 +1706,7 @@ struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
 template <>
 struct is_contiguous_back_insert_iterator<appender> : std::true_type {};
 
-// A type-erased reference to an std::locale to avoid heavy <locale> include.
+// A type-erased reference to an std::locale to avoid a heavy <locale> include.
 class locale_ref {
  private:
   const void* locale_;  // A type-erased pointer to std::locale.
@@ -1674,7 +1715,7 @@ class locale_ref {
   constexpr locale_ref() : locale_(nullptr) {}
   template <typename Locale> explicit locale_ref(const Locale& loc);
 
-  explicit operator bool() const FMT_NOEXCEPT { return locale_ != nullptr; }
+  explicit operator bool() const noexcept { return locale_ != nullptr; }
 
   template <typename Locale> auto get() const -> Locale;
 };
@@ -1690,20 +1731,8 @@ constexpr auto encode_types() -> unsigned long long {
 }
 
 template <typename Context, typename T>
-FMT_CONSTEXPR auto make_arg(const T& value) -> basic_format_arg<Context> {
-  basic_format_arg<Context> arg;
-  arg.type_ = mapped_type_constant<T, Context>::value;
-  arg.value_ = arg_mapper<Context>().map(value);
-  return arg;
-}
-
-// The type template parameter is there to avoid an ODR violation when using
-// a fallback formatter in one translation unit and an implicit conversion in
-// another (not recommended).
-template <bool IS_PACKED, typename Context, type, typename T,
-          FMT_ENABLE_IF(IS_PACKED)>
-FMT_CONSTEXPR FMT_INLINE auto make_arg(T&& val) -> value<Context> {
-  const auto& arg = arg_mapper<Context>().map(std::forward<T>(val));
+FMT_CONSTEXPR FMT_INLINE auto make_value(T&& val) -> value<Context> {
+  const auto& arg = arg_mapper<Context>().map(FMT_FORWARD(val));
 
   constexpr bool formattable_char =
       !std::is_same<decltype(arg), const unformattable_char&>::value;
@@ -1731,9 +1760,26 @@ FMT_CONSTEXPR FMT_INLINE auto make_arg(T&& val) -> value<Context> {
   return {arg};
 }
 
+template <typename Context, typename T>
+FMT_CONSTEXPR auto make_arg(T&& value) -> basic_format_arg<Context> {
+  basic_format_arg<Context> arg;
+  arg.type_ = mapped_type_constant<T, Context>::value;
+  arg.value_ = make_value<Context>(value);
+  return arg;
+}
+
+// The type template parameter is there to avoid an ODR violation when using
+// a fallback formatter in one translation unit and an implicit conversion in
+// another (not recommended).
+template <bool IS_PACKED, typename Context, type, typename T,
+          FMT_ENABLE_IF(IS_PACKED)>
+FMT_CONSTEXPR FMT_INLINE auto make_arg(T&& val) -> value<Context> {
+  return make_value<Context>(val);
+}
+
 template <bool IS_PACKED, typename Context, type, typename T,
           FMT_ENABLE_IF(!IS_PACKED)>
-inline auto make_arg(const T& value) -> basic_format_arg<Context> {
+FMT_CONSTEXPR inline auto make_arg(T&& value) -> basic_format_arg<Context> {
   return make_arg<Context>(value);
 }
 FMT_END_DETAIL_NAMESPACE
@@ -1853,7 +1899,7 @@ class format_arg_store
         data_{detail::make_arg<
             is_packed, Context,
             detail::mapped_type_constant<remove_cvref_t<T>, Context>::value>(
-            std::forward<T>(args))...} {
+            FMT_FORWARD(args))...} {
     detail::init_named_args(data_.named_args(), 0, 0, args...);
   }
 };
@@ -1869,7 +1915,7 @@ class format_arg_store
 template <typename Context = format_context, typename... Args>
 constexpr auto make_format_args(Args&&... args)
     -> format_arg_store<Context, remove_cvref_t<Args>...> {
-  return {std::forward<Args>(args)...};
+  return {FMT_FORWARD(args)...};
 }
 
 /**
@@ -2015,14 +2061,22 @@ template <typename Context> class basic_format_args {
 // between clang and gcc on ARM (#1919).
 using format_args = basic_format_args<format_context>;
 
-// We cannot use enum classes as bit fields because of a gcc bug
-// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414.
+// We cannot use enum classes as bit fields because of a gcc bug, so we put them
+// in namespaces instead (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414).
+// Additionally, if an underlying type is specified, older gcc incorrectly warns
+// that the type is too small. Both bugs are fixed in gcc 9.3.
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 903
+#  define FMT_ENUM_UNDERLYING_TYPE(type)
+#else
+#  define FMT_ENUM_UNDERLYING_TYPE(type) : type
+#endif
 namespace align {
-enum type { none, left, right, center, numeric };
+enum type FMT_ENUM_UNDERLYING_TYPE(unsigned char){none, left, right, center,
+                                                  numeric};
 }
 using align_t = align::type;
 namespace sign {
-enum type { none, minus, plus, space };
+enum type FMT_ENUM_UNDERLYING_TYPE(unsigned char){none, minus, plus, space};
 }
 using sign_t = sign::type;
 
@@ -2072,7 +2126,8 @@ enum class presentation_type : unsigned char {
   general_upper,   // 'G'
   chr,             // 'c'
   string,          // 's'
-  pointer          // 'p'
+  pointer,         // 'p'
+  debug            // '?'
 };
 
 // Format specifiers for built-in and string types.
@@ -2209,11 +2264,14 @@ class dynamic_specs_handler
 
   FMT_CONSTEXPR auto make_arg_ref(int arg_id) -> arg_ref_type {
     context_.check_arg_id(arg_id);
+    context_.check_dynamic_spec(arg_id);
     return arg_ref_type(arg_id);
   }
 
   FMT_CONSTEXPR auto make_arg_ref(auto_id) -> arg_ref_type {
-    return arg_ref_type(context_.next_arg_id());
+    int arg_id = context_.next_arg_id();
+    context_.check_dynamic_spec(arg_id);
+    return arg_ref_type(arg_id);
   }
 
   FMT_CONSTEXPR auto make_arg_ref(basic_string_view<char_type> arg_id)
@@ -2231,21 +2289,23 @@ template <typename Char> constexpr bool is_ascii_letter(Char c) {
 
 // Converts a character to ASCII. Returns a number > 127 on conversion failure.
 template <typename Char, FMT_ENABLE_IF(std::is_integral<Char>::value)>
-constexpr auto to_ascii(Char value) -> Char {
-  return value;
+constexpr auto to_ascii(Char c) -> Char {
+  return c;
 }
 template <typename Char, FMT_ENABLE_IF(std::is_enum<Char>::value)>
-constexpr auto to_ascii(Char value) ->
-    typename std::underlying_type<Char>::type {
-  return value;
+constexpr auto to_ascii(Char c) -> underlying_t<Char> {
+  return c;
+}
+
+FMT_CONSTEXPR inline auto code_point_length_impl(char c) -> int {
+  return "\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\0\0\0\0\0\0\0\0\2\2\2\2\3\3\4"
+      [static_cast<unsigned char>(c) >> 3];
 }
 
 template <typename Char>
 FMT_CONSTEXPR auto code_point_length(const Char* begin) -> int {
   if (const_check(sizeof(Char) != 1)) return 1;
-  auto lengths =
-      "\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\0\0\0\0\0\0\0\0\2\2\2\2\3\3\4";
-  int len = lengths[static_cast<unsigned char>(*begin) >> 3];
+  int len = code_point_length_impl(static_cast<char>(*begin));
 
   // Compute the pointer to the next character early so that the next
   // iteration can start working on the next character. Neither Clang
@@ -2302,7 +2362,7 @@ FMT_CONSTEXPR auto parse_align(const Char* begin, const Char* end,
   FMT_ASSERT(begin != end, "");
   auto align = align::none;
   auto p = begin + code_point_length(begin);
-  if (p >= end) p = begin;
+  if (end - p <= 0) p = begin;
   for (;;) {
     switch (to_ascii(*p)) {
     case '<':
@@ -2488,6 +2548,8 @@ FMT_CONSTEXPR auto parse_presentation_type(Char type) -> presentation_type {
     return presentation_type::string;
   case 'p':
     return presentation_type::pointer;
+  case '?':
+    return presentation_type::debug;
   default:
     return presentation_type::none;
   }
@@ -2634,22 +2696,22 @@ FMT_CONSTEXPR FMT_INLINE void parse_format_string(
     handler.on_text(begin, end);
     return;
   }
-  struct writer {
-    FMT_CONSTEXPR void operator()(const Char* pbegin, const Char* pend) {
-      if (pbegin == pend) return;
+  struct pfs_writer {
+    FMT_CONSTEXPR void operator()(const Char* from, const Char* to) {
+      if (from == to) return;
       for (;;) {
         const Char* p = nullptr;
-        if (!find<IS_CONSTEXPR>(pbegin, pend, Char('}'), p))
-          return handler_.on_text(pbegin, pend);
+        if (!find<IS_CONSTEXPR>(from, to, Char('}'), p))
+          return handler_.on_text(from, to);
         ++p;
-        if (p == pend || *p != '}')
+        if (p == to || *p != '}')
           return handler_.on_error("unmatched '}' in format string");
-        handler_.on_text(pbegin, p);
-        pbegin = p + 1;
+        handler_.on_text(from, p);
+        from = p + 1;
       }
     }
     Handler& handler_;
-  } write{handler};
+  } write = {handler};
   while (begin != end) {
     // Doing two passes with memchr (one for '{' and another for '}') is up to
     // 2.5x faster than the naive one-pass implementation on big format strings.
@@ -2661,50 +2723,29 @@ FMT_CONSTEXPR FMT_INLINE void parse_format_string(
   }
 }
 
+template <typename T, bool = is_named_arg<T>::value> struct strip_named_arg {
+  using type = T;
+};
+template <typename T> struct strip_named_arg<T, true> {
+  using type = remove_cvref_t<decltype(T::value)>;
+};
+
 template <typename T, typename ParseContext>
 FMT_CONSTEXPR auto parse_format_specs(ParseContext& ctx)
     -> decltype(ctx.begin()) {
   using char_type = typename ParseContext::char_type;
   using context = buffer_context<char_type>;
+  using stripped_type = typename strip_named_arg<T>::type;
   using mapped_type = conditional_t<
       mapped_type_constant<T, context>::value != type::custom_type,
-      decltype(arg_mapper<context>().map(std::declval<const T&>())), T>;
+      decltype(arg_mapper<context>().map(std::declval<const T&>())),
+      stripped_type>;
   auto f = conditional_t<has_formatter<mapped_type, context>::value,
                          formatter<mapped_type, char_type>,
-                         fallback_formatter<T, char_type>>();
+                         fallback_formatter<stripped_type, char_type>>();
   return f.parse(ctx);
 }
 
-// A parse context with extra argument id checks. It is only used at compile
-// time because adding checks at runtime would introduce substantial overhead
-// and would be redundant since argument ids are checked when arguments are
-// retrieved anyway.
-template <typename Char, typename ErrorHandler = error_handler>
-class compile_parse_context
-    : public basic_format_parse_context<Char, ErrorHandler> {
- private:
-  int num_args_;
-  using base = basic_format_parse_context<Char, ErrorHandler>;
-
- public:
-  explicit FMT_CONSTEXPR compile_parse_context(
-      basic_string_view<Char> format_str,
-      int num_args = (std::numeric_limits<int>::max)(), ErrorHandler eh = {})
-      : base(format_str, eh), num_args_(num_args) {}
-
-  FMT_CONSTEXPR auto next_arg_id() -> int {
-    int id = base::next_arg_id();
-    if (id >= num_args_) this->on_error("argument not found");
-    return id;
-  }
-
-  FMT_CONSTEXPR void check_arg_id(int id) {
-    base::check_arg_id(id);
-    if (id >= num_args_) this->on_error("argument not found");
-  }
-  using base::check_arg_id;
-};
-
 template <typename ErrorHandler>
 FMT_CONSTEXPR void check_int_type_spec(presentation_type type,
                                        ErrorHandler&& eh) {
@@ -2717,7 +2758,8 @@ template <typename Char, typename ErrorHandler = error_handler>
 FMT_CONSTEXPR auto check_char_specs(const basic_format_specs<Char>& specs,
                                     ErrorHandler&& eh = {}) -> bool {
   if (specs.type != presentation_type::none &&
-      specs.type != presentation_type::chr) {
+      specs.type != presentation_type::chr &&
+      specs.type != presentation_type::debug) {
     check_int_type_spec(specs.type, eh);
     return false;
   }
@@ -2741,7 +2783,6 @@ struct float_specs {
   bool upper : 1;
   bool locale : 1;
   bool binary32 : 1;
-  bool fallback : 1;
   bool showpoint : 1;
 };
 
@@ -2792,7 +2833,8 @@ FMT_CONSTEXPR auto parse_float_type_spec(const basic_format_specs<Char>& specs,
 template <typename ErrorHandler = error_handler>
 FMT_CONSTEXPR auto check_cstring_type_spec(presentation_type type,
                                            ErrorHandler&& eh = {}) -> bool {
-  if (type == presentation_type::none || type == presentation_type::string)
+  if (type == presentation_type::none || type == presentation_type::string ||
+      type == presentation_type::debug)
     return true;
   if (type != presentation_type::pointer) eh.on_error("invalid type specifier");
   return false;
@@ -2801,7 +2843,8 @@ FMT_CONSTEXPR auto check_cstring_type_spec(presentation_type type,
 template <typename ErrorHandler = error_handler>
 FMT_CONSTEXPR void check_string_type_spec(presentation_type type,
                                           ErrorHandler&& eh = {}) {
-  if (type != presentation_type::none && type != presentation_type::string)
+  if (type != presentation_type::none && type != presentation_type::string &&
+      type != presentation_type::debug)
     eh.on_error("invalid type specifier");
 }
 
@@ -2835,7 +2878,8 @@ template <typename Handler> class specs_checker : public Handler {
   FMT_CONSTEXPR void on_sign(sign_t s) {
     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) {
+        arg_type_ != type::long_long_type && arg_type_ != type::int128_type &&
+        arg_type_ != type::char_type) {
       this->on_error("format specifier requires signed argument");
     }
     Handler::on_sign(s);
@@ -2864,7 +2908,7 @@ template <typename Handler> class specs_checker : public Handler {
 
 constexpr int invalid_arg_index = -1;
 
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
 template <int N, typename T, typename... Args, typename Char>
 constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
   if constexpr (detail::is_statically_named_arg<T>()) {
@@ -2879,7 +2923,7 @@ constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
 
 template <typename... Args, typename Char>
 FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
   if constexpr (sizeof...(Args) > 0)
     return get_arg_index_by_name<0, Args...>(name);
 #endif
@@ -2890,20 +2934,28 @@ FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
 template <typename Char, typename ErrorHandler, typename... Args>
 class format_string_checker {
  private:
+  // In the future basic_format_parse_context will replace compile_parse_context
+  // here and will use is_constant_evaluated and downcasting to access the data
+  // needed for compile-time checks: https://godbolt.org/z/GvWzcTjh1.
   using parse_context_type = compile_parse_context<Char, ErrorHandler>;
-  enum { num_args = sizeof...(Args) };
+  static constexpr int num_args = sizeof...(Args);
 
   // Format specifier parsing function.
   using parse_func = const Char* (*)(parse_context_type&);
 
   parse_context_type context_;
-  parse_func parse_funcs_[num_args > 0 ? num_args : 1];
+  parse_func parse_funcs_[num_args > 0 ? static_cast<size_t>(num_args) : 1];
+  type types_[num_args > 0 ? static_cast<size_t>(num_args) : 1];
 
  public:
   explicit FMT_CONSTEXPR format_string_checker(
       basic_string_view<Char> format_str, ErrorHandler eh)
-      : context_(format_str, num_args, eh),
-        parse_funcs_{&parse_format_specs<Args, parse_context_type>...} {}
+      : context_(format_str, num_args, types_, eh),
+        parse_funcs_{&parse_format_specs<Args, parse_context_type>...},
+        types_{
+            mapped_type_constant<Args,
+                                 basic_format_context<Char*, Char>>::value...} {
+  }
 
   FMT_CONSTEXPR void on_text(const Char*, const Char*) {}
 
@@ -2912,7 +2964,7 @@ class format_string_checker {
     return context_.check_arg_id(id), id;
   }
   FMT_CONSTEXPR auto on_arg_id(basic_string_view<Char> id) -> int {
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
     auto index = get_arg_index_by_name<Args...>(id);
     if (index == invalid_arg_index) on_error("named argument is not found");
     return context_.check_arg_id(index), index;
@@ -2937,10 +2989,19 @@ class format_string_checker {
   }
 };
 
+// Reports a compile-time error if S is not a valid format string.
+template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
+FMT_INLINE void check_format_string(const S&) {
+#ifdef FMT_ENFORCE_COMPILE_STRING
+  static_assert(is_compile_string<S>::value,
+                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
+                "FMT_STRING.");
+#endif
+}
 template <typename... Args, typename S,
-          enable_if_t<(is_compile_string<S>::value), int>>
+          FMT_ENABLE_IF(is_compile_string<S>::value)>
 void check_format_string(S format_str) {
-  FMT_CONSTEXPR auto s = to_string_view(format_str);
+  FMT_CONSTEXPR auto s = basic_string_view<typename S::char_type>(format_str);
   using checker = format_string_checker<typename S::char_type, error_handler,
                                         remove_cvref_t<Args>...>;
   FMT_CONSTEXPR bool invalid_format =
@@ -3038,11 +3099,41 @@ struct formatter<T, Char,
     return it;
   }
 
+  template <detail::type U = detail::type_constant<T, Char>::value,
+            enable_if_t<(U == detail::type::string_type ||
+                         U == detail::type::cstring_type ||
+                         U == detail::type::char_type),
+                        int> = 0>
+  FMT_CONSTEXPR void set_debug_format() {
+    specs_.type = presentation_type::debug;
+  }
+
   template <typename FormatContext>
   FMT_CONSTEXPR auto format(const T& val, FormatContext& ctx) const
       -> decltype(ctx.out());
 };
 
+#define FMT_FORMAT_AS(Type, Base)                                        \
+  template <typename Char>                                               \
+  struct formatter<Type, Char> : formatter<Base, Char> {                 \
+    template <typename FormatContext>                                    \
+    auto format(Type const& val, FormatContext& ctx) const               \
+        -> decltype(ctx.out()) {                                         \
+      return formatter<Base, Char>::format(static_cast<Base>(val), ctx); \
+    }                                                                    \
+  }
+
+FMT_FORMAT_AS(signed char, int);
+FMT_FORMAT_AS(unsigned char, unsigned);
+FMT_FORMAT_AS(short, int);
+FMT_FORMAT_AS(unsigned short, unsigned);
+FMT_FORMAT_AS(long, long long);
+FMT_FORMAT_AS(unsigned long, unsigned long long);
+FMT_FORMAT_AS(Char*, const Char*);
+FMT_FORMAT_AS(std::basic_string<Char>, basic_string_view<Char>);
+FMT_FORMAT_AS(std::nullptr_t, const void*);
+FMT_FORMAT_AS(detail::std_string_view<Char>, basic_string_view<Char>);
+
 template <typename Char> struct basic_runtime { basic_string_view<Char> str; };
 
 /** A compile-time format string. */
@@ -3078,10 +3169,8 @@ template <typename Char, typename... Args> class basic_format_string {
 
 #if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
 // Workaround broken conversion on older gcc.
-template <typename... Args> using format_string = string_view;
-template <typename S> auto runtime(const S& s) -> basic_string_view<char_t<S>> {
-  return s;
-}
+template <typename...> using format_string = string_view;
+inline auto runtime(string_view s) -> string_view { return s; }
 #else
 template <typename... Args>
 using format_string = basic_format_string<char, type_identity_t<Args>...>;
@@ -3095,9 +3184,7 @@ using format_string = basic_format_string<char, type_identity_t<Args>...>;
     fmt::print(fmt::runtime("{:d}"), "I am not a number");
   \endrst
  */
-template <typename S> auto runtime(const S& s) -> basic_runtime<char_t<S>> {
-  return {{s}};
-}
+inline auto runtime(string_view s) -> basic_runtime<char> { return {{s}}; }
 #endif
 
 FMT_API auto vformat(string_view fmt, format_args args) -> std::string;