From 63ebcda94989cd1abeff342702bf2b405d73888e Mon Sep 17 00:00:00 2001
From: dajiaohuang <mikewushuwen@outlook.com>
Date: Sun, 13 Sep 2026 23:39:29 +0800
Subject: [PATCH 1/3] Fix format_as for tuple-like types

---
 include/fmt/ranges.h |  7 ++++++-
 test/ranges-test.cc  | 17 +++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/include/fmt/ranges.h b/include/fmt/ranges.h
index 678df0f1032e..b4fd20f034b9 100644
--- a/include/fmt/ranges.h
+++ b/include/fmt/ranges.h
@@ -164,7 +164,12 @@ using make_index_sequence = make_integer_sequence<size_t, N>;
 template <typename T>
 using tuple_index_sequence = make_index_sequence<std::tuple_size<T>::value>;
 
-template <typename T, typename C, bool = is_tuple_like_<T>::value>
+template <typename T, typename = void> struct has_format_as_ : std::false_type {};
+template <typename T>
+struct has_format_as_<T, void_t<format_as_result<T>>> : std::true_type {};
+
+template <typename T, typename C,
+          bool = is_tuple_like_<T>::value && !has_format_as_<T>::value>
 class is_tuple_formattable_ {
  public:
   static constexpr bool value = false;
diff --git a/test/ranges-test.cc b/test/ranges-test.cc
index d3ca6498faac..9cdbb2019514 100644
--- a/test/ranges-test.cc
+++ b/test/ranges-test.cc
@@ -721,6 +721,23 @@ TEST(ranges_test, format_as_tie) {
   EXPECT_EQ(fmt::format("{}", tieable()), "(3, 0.42)");
 }
 
+struct format_as_tuple_like {};
+
+auto format_as(const format_as_tuple_like&) -> std::string { return "Hello"; }
+
+namespace std {
+template <> struct tuple_size<format_as_tuple_like>
+    : integral_constant<size_t, 1> {};
+template <> struct tuple_element<0, format_as_tuple_like> {
+  using type = format_as_tuple_like;
+};
+}  // namespace std
+
+TEST(ranges_test, format_as_tuple_like) {
+  EXPECT_TRUE((fmt::is_formattable<format_as_tuple_like>::value));
+  EXPECT_EQ(fmt::format("{}", format_as_tuple_like{}), "Hello");
+}
+
 struct lvalue_qualified_begin_end {
   int arr[5] = {1, 2, 3, 4, 5};
 

From 7881fc217b9a8d389cb2d022943b354c5dec09f6 Mon Sep 17 00:00:00 2001
From: dajiaohuang <mikewushuwen@outlook.com>
Date: Sun, 13 Sep 2026 23:43:42 +0800
Subject: [PATCH 2/3] Format format_as tuple trait declaration

---
 include/fmt/ranges.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/fmt/ranges.h b/include/fmt/ranges.h
index b4fd20f034b9..cfff028f93e8 100644
--- a/include/fmt/ranges.h
+++ b/include/fmt/ranges.h
@@ -164,7 +164,8 @@ using make_index_sequence = make_integer_sequence<size_t, N>;
 template <typename T>
 using tuple_index_sequence = make_index_sequence<std::tuple_size<T>::value>;
 
-template <typename T, typename = void> struct has_format_as_ : std::false_type {};
+template <typename T, typename = void>
+struct has_format_as_ : std::false_type {};
 template <typename T>
 struct has_format_as_<T, void_t<format_as_result<T>>> : std::true_type {};
 

From 4d5286b435ab8518c48aa92bd5bb86cd374163aa Mon Sep 17 00:00:00 2001
From: dajiaohuang <mikewushuwen@outlook.com>
Date: Thu, 17 Sep 2026 00:01:13 +0800
Subject: [PATCH 3/3] Fix tuple formattability with format_as

---
 include/fmt/ranges.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/fmt/ranges.h b/include/fmt/ranges.h
index cfff028f93e8..b40a68dfe521 100644
--- a/include/fmt/ranges.h
+++ b/include/fmt/ranges.h
@@ -303,10 +303,20 @@ template <typename T, typename C> struct is_tuple_formattable {
   static constexpr bool value = detail::is_tuple_formattable_<T, C>::value;
 };
 
+namespace detail {
+template <typename T, typename C, bool = has_format_as_<T>::value>
+struct is_tuple_formattable_for_formatter : std::false_type {};
+
+template <typename T, typename C>
+struct is_tuple_formattable_for_formatter<T, C, false>
+    : std::integral_constant<bool, fmt::is_tuple_formattable<T, C>::value> {};
+}  // namespace detail
+
 template <typename Tuple, typename Char>
 struct formatter<Tuple, Char,
                  enable_if_t<fmt::is_tuple_like<Tuple>::value &&
-                             fmt::is_tuple_formattable<Tuple, Char>::value>> {
+                             detail::is_tuple_formattable_for_formatter<
+                                 Tuple, Char>::value>> {
  private:
   decltype(detail::tuple::get_formatters<Tuple, Char>(
       detail::tuple_index_sequence<Tuple>())) formatters_;