[libcxx-commits] [libcxx] [libc++] Implement comparison operators for `tuple` added in C++23 (PR #148799)

via libcxx-commits libcxx-commits at lists.llvm.org
Tue Jul 15 01:02:18 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: A. Jiang (frederick-vs-ja)

<details>
<summary>Changes</summary>

And constrain the new `operator==` since C++26.

This patch implements parts of P2165R4, P2944R3, and a possibly improved resolution of LWG3882. Currently, libstdc++ and MSVC STL constrain the new overloads in the same way.

Fixes #<!-- -->136765.

---

Patch is 42.85 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/148799.diff


8 Files Affected:

- (modified) libcxx/docs/Status/Cxx23Papers.csv (+1-1) 
- (modified) libcxx/docs/Status/Cxx2cIssues.csv (+1) 
- (modified) libcxx/docs/Status/Cxx2cPapers.csv (+1-1) 
- (modified) libcxx/include/tuple (+103-27) 
- (modified) libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp (+249-131) 
- (modified) libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp (+294-175) 
- (modified) libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/size_incompatible_three_way.compile.pass.cpp (+17-2) 
- (modified) libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/three_way.pass.cpp (+155-17) 


``````````diff
diff --git a/libcxx/docs/Status/Cxx23Papers.csv b/libcxx/docs/Status/Cxx23Papers.csv
index e4fa07d82289d..f1d8e9a2bd09c 100644
--- a/libcxx/docs/Status/Cxx23Papers.csv
+++ b/libcxx/docs/Status/Cxx23Papers.csv
@@ -60,7 +60,7 @@
 "`P1642R11 <https://wg21.link/P1642R11>`__","Freestanding ``[utilities]``, ``[ranges]``, and ``[iterators]``","2022-07 (Virtual)","","",""
 "`P1899R3 <https://wg21.link/P1899R3>`__","``stride_view``","2022-07 (Virtual)","","",""
 "`P2093R14 <https://wg21.link/P2093R14>`__","Formatted output","2022-07 (Virtual)","|Complete|","18",""
-"`P2165R4 <https://wg21.link/P2165R4>`__","Compatibility between ``tuple``, ``pair`` and ``tuple-like`` objects","2022-07 (Virtual)","|Partial|","","Only the part for ``zip_view`` is implemented."
+"`P2165R4 <https://wg21.link/P2165R4>`__","Compatibility between ``tuple``, ``pair`` and ``tuple-like`` objects","2022-07 (Virtual)","|Partial|","","Changes of ``tuple``, ``adjacent_view``, and ``cartesian_product_view`` are not yet implemented."
 "`P2278R4 <https://wg21.link/P2278R4>`__","``cbegin`` should always return a constant iterator","2022-07 (Virtual)","","",""
 "`P2286R8 <https://wg21.link/P2286R8>`__","Formatting Ranges","2022-07 (Virtual)","|Complete|","16",""
 "`P2291R3 <https://wg21.link/P2291R3>`__","Add Constexpr Modifiers to Functions ``to_chars`` and ``from_chars`` for Integral Types in ``<charconv>`` Header","2022-07 (Virtual)","|Complete|","16",""
diff --git a/libcxx/docs/Status/Cxx2cIssues.csv b/libcxx/docs/Status/Cxx2cIssues.csv
index c8a3aa95b7480..70ef723cd2b02 100644
--- a/libcxx/docs/Status/Cxx2cIssues.csv
+++ b/libcxx/docs/Status/Cxx2cIssues.csv
@@ -149,4 +149,5 @@
 "`LWG3343 <https://wg21.link/LWG3343>`__","Ordering of calls to ``unlock()`` and ``notify_all()`` in Effects element of ``notify_all_at_thread_exit()`` should be reversed","Not Adopted Yet","|Complete|","16",""
 "`LWG4139 <https://wg21.link/LWG4139>`__","ยง[time.zone.leap] recursive constraint in <=>","Not Adopted Yet","|Complete|","20",""
 "`LWG3456 <https://wg21.link/LWG3456>`__","Pattern used by std::from_chars is underspecified (option B)","Not Adopted Yet","|Complete|","20",""
+"`LWG3882 <https://wg21.link/LWG3882>`__","``tuple`` relational operators have confused friendships","Not Adopted Yet","|Complete|","21","The comparsion operators are constrained harder than the proposed resolution. libstdc++ and MSVC STL do the same."
 "","","","","",""
diff --git a/libcxx/docs/Status/Cxx2cPapers.csv b/libcxx/docs/Status/Cxx2cPapers.csv
index a1854a6acc41a..6d9f245ab200d 100644
--- a/libcxx/docs/Status/Cxx2cPapers.csv
+++ b/libcxx/docs/Status/Cxx2cPapers.csv
@@ -59,7 +59,7 @@
 "`P2248R8 <https://wg21.link/P2248R8>`__","Enabling list-initialization for algorithms","2024-03 (Tokyo)","","",""
 "`P2810R4 <https://wg21.link/P2810R4>`__","``is_debugger_present`` ``is_replaceable``","2024-03 (Tokyo)","","",""
 "`P1068R11 <https://wg21.link/P1068R11>`__","Vector API for random number generation","2024-03 (Tokyo)","","",""
-"`P2944R3 <https://wg21.link/P2944R3>`__","Comparisons for ``reference_wrapper``","2024-03 (Tokyo)","|Partial|","","The changes to ``optional`` and ``tuple``'s equality overload from P2165R4 are not yet implemented"
+"`P2944R3 <https://wg21.link/P2944R3>`__","Comparisons for ``reference_wrapper``","2024-03 (Tokyo)","|Partial|","","The changes to ``optional`` are not yet implemented"
 "`P2642R6 <https://wg21.link/P2642R6>`__","Padded ``mdspan`` layouts","2024-03 (Tokyo)","","",""
 "`P3029R1 <https://wg21.link/P3029R1>`__","Better ``mdspan``'s CTAD","2024-03 (Tokyo)","|Complete|","19",""
 "","","","","",""
diff --git a/libcxx/include/tuple b/libcxx/include/tuple
index 75021f0ea51f6..94cdf9d779304 100644
--- a/libcxx/include/tuple
+++ b/libcxx/include/tuple
@@ -230,6 +230,7 @@ template <class... Types>
 #  include <__tuple/sfinae_helpers.h>
 #  include <__tuple/tuple_element.h>
 #  include <__tuple/tuple_indices.h>
+#  include <__tuple/tuple_like.h>
 #  include <__tuple/tuple_like_ext.h>
 #  include <__tuple/tuple_size.h>
 #  include <__tuple/tuple_types.h>
@@ -288,6 +289,72 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #  ifndef _LIBCPP_CXX03_LANG
 
+template <size_t _Ip>
+struct __tuple_equal {
+  template <class _Tp, class _Up>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
+    return __tuple_equal<_Ip - 1>()(__x, __y) && std::get<_Ip - 1>(__x) == std::get<_Ip - 1>(__y);
+  }
+
+#    if _LIBCPP_STD_VER >= 26
+  template <class _Tp, class _Up>
+  static constexpr bool __can_compare =
+      __tuple_equal<_Ip - 1>::template __can_compare<_Tp, _Up> && requires(const _Tp& __x, const _Up& __y) {
+        { std::get<_Ip - 1>(__x) == std::get<_Ip - 1>(__y) } -> __boolean_testable;
+      };
+#    endif // _LIBCPP_STD_VER >= 26
+};
+
+template <>
+struct __tuple_equal<0> {
+  template <class _Tp, class _Up>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
+    return true;
+  }
+
+#    if _LIBCPP_STD_VER >= 26
+  template <class _Tp, class _Up>
+  static constexpr bool __can_compare = true;
+#    endif // _LIBCPP_STD_VER >= 26
+};
+
+#    if _LIBCPP_STD_VER >= 20
+template <class _Ret, class _Tp, class _Up, size_t... _Is>
+_LIBCPP_HIDE_FROM_ABI constexpr _Ret __tuple_compare_three_way(const _Tp& __x, const _Up& __y, index_sequence<_Is...>) {
+  _Ret __result = strong_ordering::equal;
+  static_cast<void>(
+      ((__result = std::__synth_three_way(std::get<_Is>(__x), std::get<_Is>(__y)), __result != 0) || ...));
+  return __result;
+}
+#    endif // _LIBCPP_STD_VER >= 20
+
+#    if _LIBCPP_STD_VER >= 23
+template <class>
+inline constexpr bool __is_tuple_v = false;
+
+template <class... _Tp>
+inline constexpr bool __is_tuple_v<tuple<_Tp...>> = true;
+
+template <class _Tp>
+concept __tuple_like_no_tuple = __tuple_like<_Tp> && !__is_tuple_v<_Tp>;
+
+template <class _Tp, class _Up, class _IndexSeq>
+struct __tuple_common_comparison_category_impl {};
+template <class _Tp, class _Up, size_t... _Indices>
+  requires requires {
+    typename common_comparison_category_t<
+        __synth_three_way_result<tuple_element_t<_Indices, _Tp>, tuple_element_t<_Indices, _Up>>...>;
+  }
+struct __tuple_common_comparison_category_impl<_Tp, _Up, index_sequence<_Indices...>> {
+  using type _LIBCPP_NODEBUG = common_comparison_category_t<
+      __synth_three_way_result<tuple_element_t<_Indices, _Tp>, tuple_element_t<_Indices, _Up>>...>;
+};
+
+template <__tuple_like _Tp, __tuple_like _Up>
+using __tuple_common_comparison_category _LIBCPP_NODEBUG =
+    __tuple_common_comparison_category_impl<_Tp, _Up, make_index_sequence<tuple_size_v<_Tp>>>::type;
+#    endif // _LIBCPP_STD_VER >= 23
+
 // __tuple_leaf
 
 template <size_t _Ip, class _Hp, bool = is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value >
@@ -997,7 +1064,25 @@ public:
       noexcept(__all<is_nothrow_swappable_v<const _Tp&>...>::value) {
     __base_.swap(__t.__base_);
   }
-#    endif // _LIBCPP_STD_VER >= 23
+
+  template <__tuple_like_no_tuple _UTuple>
+#      if _LIBCPP_STD_VER >= 26
+    requires(__tuple_equal<sizeof...(_Tp)>::template __can_compare<tuple, _UTuple>) &&
+            (sizeof...(_Tp) == tuple_size_v<_UTuple>)
+#      endif // _LIBCPP_STD_VER >= 26
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const tuple& __x, const _UTuple& __y) {
+    static_assert(sizeof...(_Tp) == tuple_size_v<_UTuple>, "Can't compare tuple-like values of different sizes");
+    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
+  }
+
+  template <__tuple_like_no_tuple _UTuple>
+    requires(sizeof...(_Tp) == tuple_size_v<_UTuple>)
+  _LIBCPP_HIDE_FROM_ABI friend constexpr __tuple_common_comparison_category<tuple, _UTuple>
+  operator<=>(const tuple& __x, const _UTuple& __y) {
+    return std::__tuple_compare_three_way<__tuple_common_comparison_category<tuple, _UTuple>>(
+        __x, __y, index_sequence_for<_Tp...>{});
+  }
+#    endif   // _LIBCPP_STD_VER >= 23
 };
 
 _LIBCPP_DIAGNOSTIC_PUSH
@@ -1019,6 +1104,21 @@ public:
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple&) _NOEXCEPT {}
 #    if _LIBCPP_STD_VER >= 23
   _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple&) const noexcept {}
+
+  template <__tuple_like_no_tuple _UTuple>
+#      if _LIBCPP_STD_VER >= 26
+    requires(tuple_size_v<_UTuple> == 0)
+#      endif // _LIBCPP_STD_VER >= 26
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const tuple& __x, const _UTuple& __y) {
+    static_assert(tuple_size_v<_UTuple> == 0, "Can't compare tuple-like values of different sizes");
+    return true;
+  }
+
+  template <__tuple_like_no_tuple _UTuple>
+    requires(tuple_size_v<_UTuple> == 0)
+  _LIBCPP_HIDE_FROM_ABI friend constexpr strong_ordering operator<=>(const tuple& __x, const _UTuple& __y) {
+    return strong_ordering::equal;
+  }
 #    endif
 };
 _LIBCPP_DIAGNOSTIC_POP
@@ -1137,22 +1237,6 @@ inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<_Tp&&...> forwa
   return tuple<_Tp&&...>(std::forward<_Tp>(__t)...);
 }
 
-template <size_t _Ip>
-struct __tuple_equal {
-  template <class _Tp, class _Up>
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
-    return __tuple_equal<_Ip - 1>()(__x, __y) && std::get<_Ip - 1>(__x) == std::get<_Ip - 1>(__y);
-  }
-};
-
-template <>
-struct __tuple_equal<0> {
-  template <class _Tp, class _Up>
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
-    return true;
-  }
-};
-
 template <class... _Tp, class... _Up>
 #    if _LIBCPP_STD_VER >= 26
   requires(__all<requires(const _Tp& __t, const _Up& __u) {
@@ -1169,20 +1253,12 @@ operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
 
 // operator<=>
 
-template <class... _Tp, class... _Up, size_t... _Is>
-_LIBCPP_HIDE_FROM_ABI constexpr auto
-__tuple_compare_three_way(const tuple<_Tp...>& __x, const tuple<_Up...>& __y, index_sequence<_Is...>) {
-  common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...> __result = strong_ordering::equal;
-  static_cast<void>(
-      ((__result = std::__synth_three_way(std::get<_Is>(__x), std::get<_Is>(__y)), __result != 0) || ...));
-  return __result;
-}
-
 template <class... _Tp, class... _Up>
   requires(sizeof...(_Tp) == sizeof...(_Up))
 _LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>
 operator<=>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
-  return std::__tuple_compare_three_way(__x, __y, index_sequence_for<_Tp...>{});
+  return std::__tuple_compare_three_way<common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>>(
+      __x, __y, index_sequence_for<_Tp...>{});
 }
 
 #    else // _LIBCPP_STD_VER >= 20
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
index 779a89b163f04..b0301f3ad93e7 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
@@ -13,6 +13,8 @@
 // template<class... TTypes, class... UTypes>
 //   bool
 //   operator==(const tuple<TTypes...>& t, const tuple<UTypes...>& u);
+// template<tuple-like UTuple>
+//   friend constexpr bool operator==(const tuple& t, const UTuple& u); // since C++23
 
 // UNSUPPORTED: c++03
 
@@ -23,6 +25,13 @@
 #include "test_comparisons.h"
 #include "test_macros.h"
 
+#if TEST_STD_VER >= 23
+#  include <ranges>
+#endif
+#if TEST_STD_VER >= 26
+#  include <complex>
+#endif
+
 #if TEST_STD_VER >= 26
 
 // Test SFINAE.
@@ -41,140 +50,249 @@ static_assert(
 static_assert(
     !std::equality_comparable_with<std::tuple<EqualityComparable, EqualityComparable>, std::tuple<EqualityComparable>>);
 
+// Heterogeneous comparisons.
+// TODO: Use equality_comparable_with once other changes of tuple introduced in P2165R4 are implemented.
+template <class T, class U>
+concept can_eq_compare = requires(const T& t, const U& u) { t == u; };
+
+static_assert(can_eq_compare<std::tuple<EqualityComparable>, std::array<EqualityComparable, 1>>);
+static_assert(!can_eq_compare<std::tuple<EqualityComparable>, std::array<NonComparable, 1>>);
+
+static_assert(can_eq_compare<std::tuple<EqualityComparable, EqualityComparable>,
+                             std::pair<EqualityComparable, EqualityComparable>>);
+static_assert(
+    !can_eq_compare<std::tuple<EqualityComparable, EqualityComparable>, std::pair<EqualityComparable, NonComparable>>);
+
+static_assert(can_eq_compare<std::tuple<int*, int*>, std::ranges::subrange<const int*>>);
+static_assert(!can_eq_compare<std::tuple<int (*)[1], int (*)[1]>, std::ranges::subrange<const int*>>);
+static_assert(can_eq_compare<std::tuple<double, double>, std::complex<float>>);
+static_assert(!can_eq_compare<std::tuple<int*, int*>, std::complex<float>>);
+
+// Size mismatch in heterogeneous comparisons.
+static_assert(!can_eq_compare<std::tuple<>, std::array<EqualityComparable, 2>>);
+static_assert(!can_eq_compare<std::tuple<EqualityComparable>, std::array<EqualityComparable, 2>>);
+static_assert(!can_eq_compare<std::tuple<>, std::pair<EqualityComparable, EqualityComparable>>);
+static_assert(!can_eq_compare<std::tuple<EqualityComparable>, std::pair<EqualityComparable, EqualityComparable>>);
+static_assert(!can_eq_compare<std::tuple<int*>, std::ranges::subrange<int*>>);
+static_assert(!can_eq_compare<std::tuple<double>, std::complex<double>>);
+
 #endif
 
-int main(int, char**)
-{
-    {
-        typedef std::tuple<> T1;
-        typedef std::tuple<> T2;
-        const T1 t1;
-        const T2 t2;
-        assert(t1 == t2);
-        assert(!(t1 != t2));
-    }
-    {
-        typedef std::tuple<int> T1;
-        typedef std::tuple<double> T2;
-        const T1 t1(1);
-        const T2 t2(1.1);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<int> T1;
-        typedef std::tuple<double> T2;
-        const T1 t1(1);
-        const T2 t2(1);
-        assert(t1 == t2);
-        assert(!(t1 != t2));
-    }
-    {
-        typedef std::tuple<int, double> T1;
-        typedef std::tuple<double, long> T2;
-        const T1 t1(1, 2);
-        const T2 t2(1, 2);
-        assert(t1 == t2);
-        assert(!(t1 != t2));
-    }
-    {
-        typedef std::tuple<int, double> T1;
-        typedef std::tuple<double, long> T2;
-        const T1 t1(1, 2);
-        const T2 t2(1, 3);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<int, double> T1;
-        typedef std::tuple<double, long> T2;
-        const T1 t1(1, 2);
-        const T2 t2(1.1, 2);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<int, double> T1;
-        typedef std::tuple<double, long> T2;
-        const T1 t1(1, 2);
-        const T2 t2(1.1, 3);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1, 2, 3);
-        assert(t1 == t2);
-        assert(!(t1 != t2));
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1.1, 2, 3);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1, 3, 3);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1, 2, 4);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1, 3, 2);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1.1, 2, 2);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1.1, 3, 3);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        const T1 t1(1, 2, 3);
-        const T2 t2(1.1, 3, 2);
-        assert(!(t1 == t2));
-        assert(t1 != t2);
-    }
-#if TEST_STD_VER > 11
-    {
-        typedef std::tuple<long, int, double> T1;
-        typedef std::tuple<double, long, int> T2;
-        constexpr T1 t1(1, 2, 3);
-        constexpr T2 t2(1.1, 3, 2);
-        static_assert(!(t1 == t2), "");
-        static_assert(t1 != t2, "");
-    }
+TEST_CONSTEXPR_CXX14 bool test() {
+  {
+    typedef std::tuple<> T1;
+    typedef std::tuple<> T2;
+    const T1 t1;
+    const T2 t2;
+    assert(t1 == t2);
+    assert(!(t1 != t2));
+  }
+  {
+    typedef std::tuple<int> T1;
+    typedef std::tuple<double> T2;
+    const T1 t1(1);
+    const T2 t2(1.1);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<int> T1;
+    typedef std::tuple<double> T2;
+    const T1 t1(1);
+    const T2 t2(1);
+    assert(t1 == t2);
+    assert(!(t1 != t2));
+  }
+  {
+    typedef std::tuple<int, double> T1;
+    typedef std::tuple<double, long> T2;
+    const T1 t1(1, 2);
+    const T2 t2(1, 2);
+    assert(t1 == t2);
+    assert(!(t1 != t2));
+  }
+  {
+    typedef std::tuple<int, double> T1;
+    typedef std::tuple<double, long> T2;
+    const T1 t1(1, 2);
+    const T2 t2(1, 3);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<int, double> T1;
+    typedef std::tuple<double, long> T2;
+    const T1 t1(1, 2);
+    const T2 t2(1.1, 2);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<int, double> T1;
+    typedef std::tuple<double, long> T2;
+    const T1 t1(1, 2);
+    const T2 t2(1.1, 3);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1, 2, 3);
+    assert(t1 == t2);
+    assert(!(t1 != t2));
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1.1, 2, 3);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1, 3, 3);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1, 2, 4);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1, 3, 2);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1.1, 2, 2);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1.1, 3, 3);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+  {
+    typedef std::tuple<long, int, double> T1;
+    typedef std::tuple<double, long, int> T2;
+    const T1 t1(1, 2, 3);
+    const T2 t2(1.1, 3, 2);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
+#if TEST_STD_VER >= 14
+  {
+    using T1 = std::tuple<long, int, double>;
+    using T2 = std::tuple<double, long, int>;
+    constexpr T1 t1(1, 2, 3);
+    constexpr T2 t2(1.1, 3, 2);
+    assert(!(t1 == t2));
+    assert(t1 != t2);
+  }
 #endif
+#if TEST_STD_VER >= 23
+  {
+    using T1 = std::tuple<long, int>;
...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/148799


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