Simplify byte handling

include/fmt/core.h

@@ -8,7 +8,6 @@
 #ifndef FMT_CORE_H_
 #define FMT_CORE_H_
 
-#include <cstddef>  // std::byte
 #include <cstdio>   // std::FILE
 #include <cstring>
 #include <iterator>
@@ -367,12 +366,6 @@ 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)
@@ -1429,10 +1422,6 @@ template <typename Context> struct arg_mapper {
     return map(format_as(val));
   }
 
-  FMT_CONSTEXPR FMT_INLINE auto map(detail::byte val) -> unsigned {
-    return map(static_cast<unsigned char>(val));
-  }
-
   template <typename T, typename U = remove_cvref_t<T>>
   struct formattable
       : bool_constant<has_const_formatter<U, Context>() ||

include/fmt/format.h

@@ -34,6 +34,7 @@
 #define FMT_FORMAT_H_
 
 #include <cmath>         // std::signbit
+#include <cstddef>       // std::byte
 #include <cstdint>       // uint32_t
 #include <cstring>       // std::memcpy
 #include <limits>        // std::numeric_limits
@@ -159,8 +160,8 @@ FMT_END_NAMESPACE
 // __builtin_ctz is broken in Intel Compiler Classic on Windows:
 // https://github.com/fmtlib/fmt/issues/2510.
 #ifndef __ICL
-#  if FMT_HAS_BUILTIN(__builtin_ctz) || FMT_GCC_VERSION || \
-      FMT_ICC_VERSION || FMT_NVCOMPILER_VERSION
+#  if FMT_HAS_BUILTIN(__builtin_ctz) || FMT_GCC_VERSION || FMT_ICC_VERSION || \
+      FMT_NVCOMPILER_VERSION
 #    define FMT_BUILTIN_CTZ(n) __builtin_ctz(n)
 #  endif
 #  if FMT_HAS_BUILTIN(__builtin_ctzll) || FMT_GCC_VERSION || \
@@ -2767,7 +2768,6 @@ 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::byte, unsigned char);
 FMT_FORMAT_AS(detail::std_string_view<Char>, basic_string_view<Char>);
 
 template <typename Char>
@@ -2875,6 +2875,11 @@ constexpr auto underlying(Enum e) noexcept ->
   return static_cast<typename std::underlying_type<Enum>::type>(e);
 }
 
+#ifdef __cpp_lib_byte
+inline auto format_as(std::byte b) -> unsigned char { return underlying(b); }
+FMT_FORMAT_AS(std::byte, unsigned char);
+#endif
+
 class bytes {
  private:
   string_view data_;