From b5c4d25cd13209944b9a018c8a242377839fe510 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@meta.com>
Date: Sun, 24 Aug 2025 09:30:50 -0700
Subject: [PATCH] Rename is_char to is_code_unit

---
 include/fmt/base.h | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/include/fmt/base.h b/include/fmt/base.h
index a97c298a..38f9b523 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -903,24 +903,20 @@ FMT_END_EXPORT
 
 namespace detail {
 
-// DEPRECATED! Will be merged with is_char
-template <typename T> struct is_xchar : std::false_type {};
-template <> struct is_xchar<wchar_t> : std::true_type {};
-template <> struct is_xchar<char16_t> : std::true_type {};
-template <> struct is_xchar<char32_t> : std::true_type {};
+// Specifies if `T` is a code unit type.
+template <typename T> struct is_code_unit : std::false_type {};
+template <> struct is_code_unit<char> : std::true_type {};
+template <> struct is_code_unit<wchar_t> : std::true_type {};
+template <> struct is_code_unit<char16_t> : std::true_type {};
+template <> struct is_code_unit<char32_t> : std::true_type {};
 #ifdef __cpp_char8_t
-template <>
-struct is_xchar<char8_t> : bool_constant<detail::is_utf8_enabled> {};
+template <> struct is_code_unit<char8_t> : bool_constant<is_utf8_enabled> {};
 #endif
 
-// Specifies if `T` is a character (code unit) type.
-template <typename T> struct is_char : is_xchar<T> {};
-template <> struct is_char<char> : std::true_type {};
-
 // Constructs fmt::basic_string_view<Char> from types implicitly convertible
 // to it, deducing Char. Explicitly convertible types such as the ones returned
 // from FMT_STRING are intentionally excluded.
-template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
+template <typename Char, FMT_ENABLE_IF(is_code_unit<Char>::value)>
 constexpr auto to_string_view(const Char* s) -> basic_string_view<Char> {
   return s;
 }
@@ -1165,7 +1161,7 @@ template <typename Char> struct type_mapper {
   static auto map(ubitint<N>)
       -> conditional_t<N <= 64, unsigned long long, void>;
 
-  template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
+  template <typename T, FMT_ENABLE_IF(is_code_unit<T>::value)>
   static auto map(T) -> conditional_t<
       std::is_same<T, char>::value || std::is_same<T, Char>::value, Char, void>;
 
@@ -2185,7 +2181,7 @@ template <typename Context> class value {
     static_assert(N <= 64, "unsupported _BitInt");
   }
 
-  template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
+  template <typename T, FMT_ENABLE_IF(is_code_unit<T>::value)>
   constexpr FMT_INLINE value(T x FMT_BUILTIN) : char_value(x) {
     static_assert(
         std::is_same<T, char>::value || std::is_same<T, char_type>::value,