[libc++] Remove _LIBCPP_DISABLE_NODISCARD_EXTENSIONS and refactor the…

… tests
llvm · Apr 20, 2024 · 73cd60d · 73cd60d
1 parent fa61f06
commit 73cd60d
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diff --git a/libcxx/.clang-format b/libcxx/.clang-format
@@ -44,7 +44,6 @@ AttributeMacros: [
                   '_LIBCPP_NO_SANITIZE',
                   '_LIBCPP_NO_UNIQUE_ADDRESS',
                   '_LIBCPP_NOALIAS',
-                  '_LIBCPP_NODISCARD_EXT',
                   '_LIBCPP_NODISCARD',
                   '_LIBCPP_NORETURN',
                   '_LIBCPP_OVERRIDABLE_FUNC_VIS',

diff --git a/libcxx/docs/ReleaseNotes/19.rst b/libcxx/docs/ReleaseNotes/19.rst
@@ -79,6 +79,10 @@ Deprecations and Removals
   in language modes prior to C++20. If you are using these features prior to C++20, please update to ``-std=c++20``.
   In LLVM 20, the C++20 synchronization library will be removed entirely in language modes prior to C++20.
 
+- ``_LIBCPP_DISABLE_NODISCARD_EXT`` has been removed. ``[[nodiscard]]`` applications are now unconditional.
+  This decision is based on LEWGs discussion on `P3122 <https://wg21.link/P3122>` and `P3162 <https://wg21.link/P3162>`
+  to not use ``[[nodiscard]]`` in the standard.
+
 - TODO: The ``LIBCXX_ENABLE_ASSERTIONS`` CMake variable that was used to enable the safe mode has been deprecated and setting
   it triggers an error; use the ``LIBCXX_HARDENING_MODE`` CMake variable with the value ``extensive`` instead. Similarly,
   the ``_LIBCPP_ENABLE_ASSERTIONS`` macro has been deprecated (setting it to ``1`` still enables the extensive mode in

diff --git a/libcxx/docs/UsingLibcxx.rst b/libcxx/docs/UsingLibcxx.rst
@@ -196,10 +196,6 @@ safety annotations.
   replacement scenarios from working, e.g. replacing `operator new` and
   expecting a non-replaced `operator new[]` to call the replaced `operator new`.
 
-**_LIBCPP_DISABLE_NODISCARD_EXT**:
-  This macro disables library-extensions of ``[[nodiscard]]``.
-  See :ref:`Extended Applications of [[nodiscard]] <nodiscard extension>` for more information.
-
 **_LIBCPP_DISABLE_DEPRECATION_WARNINGS**:
   This macro disables warnings when using deprecated components. For example,
   using `std::auto_ptr` when compiling in C++11 mode will normally trigger a
@@ -279,29 +275,6 @@ Libc++ Extensions
 This section documents various extensions provided by libc++, how they're
 provided, and any information regarding how to use them.
 
-.. _nodiscard extension:
-
-Extended applications of ``[[nodiscard]]``
-------------------------------------------
-
-The ``[[nodiscard]]`` attribute is intended to help users find bugs where
-function return values are ignored when they shouldn't be. After C++17 the
-C++ standard has started to declared such library functions as ``[[nodiscard]]``.
-However, this application is limited and applies only to dialects after C++17.
-Users who want help diagnosing misuses of STL functions may desire a more
-liberal application of ``[[nodiscard]]``.
-
-For this reason libc++ provides an extension that does just that! The
-extension is enabled by default and can be disabled by defining ``_LIBCPP_DISABLE_NODISCARD_EXT``.
-The extended applications of ``[[nodiscard]]`` takes two forms:
-
-1. Backporting ``[[nodiscard]]`` to entities declared as such by the
-   standard in newer dialects, but not in the present one.
-
-2. Extended applications of ``[[nodiscard]]``, at the library's discretion,
-   applied to entities never declared as such by the standard. You can find
-   all such applications by grepping for ``_LIBCPP_NODISCARD_EXT``.
-
 Extended integral type support
 ------------------------------
 

diff --git a/libcxx/include/__algorithm/adjacent_find.h b/libcxx/include/__algorithm/adjacent_find.h
@@ -26,7 +26,7 @@ _LIBCPP_PUSH_MACROS
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Iter, class _Sent, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter
+_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter
 __adjacent_find(_Iter __first, _Sent __last, _BinaryPredicate&& __pred) {
   if (__first == __last)
     return __first;
@@ -40,13 +40,13 @@ __adjacent_find(_Iter __first, _Sent __last, _BinaryPredicate&& __pred) {
 }
 
 template <class _ForwardIterator, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
 adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred) {
   return std::__adjacent_find(std::move(__first), std::move(__last), __pred);
 }
 
 template <class _ForwardIterator>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
 adjacent_find(_ForwardIterator __first, _ForwardIterator __last) {
   return std::adjacent_find(std::move(__first), std::move(__last), __equal_to());
 }

diff --git a/libcxx/include/__algorithm/all_of.h b/libcxx/include/__algorithm/all_of.h
@@ -19,7 +19,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   for (; __first != __last; ++__first)
     if (!__pred(*__first))

diff --git a/libcxx/include/__algorithm/any_of.h b/libcxx/include/__algorithm/any_of.h
@@ -19,7 +19,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   for (; __first != __last; ++__first)
     if (__pred(*__first))

diff --git a/libcxx/include/__algorithm/binary_search.h b/libcxx/include/__algorithm/binary_search.h
@@ -22,14 +22,14 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _ForwardIterator, class _Tp, class _Compare>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
   __first = std::lower_bound<_ForwardIterator, _Tp, __comp_ref_type<_Compare> >(__first, __last, __value, __comp);
   return __first != __last && !__comp(__value, *__first);
 }
 
 template <class _ForwardIterator, class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
   return std::binary_search(__first, __last, __value, __less<>());
 }

diff --git a/libcxx/include/__algorithm/clamp.h b/libcxx/include/__algorithm/clamp.h
@@ -21,7 +21,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp, class _Compare>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
 clamp(_LIBCPP_LIFETIMEBOUND const _Tp& __v,
       _LIBCPP_LIFETIMEBOUND const _Tp& __lo,
       _LIBCPP_LIFETIMEBOUND const _Tp& __hi,
@@ -31,7 +31,7 @@ clamp(_LIBCPP_LIFETIMEBOUND const _Tp& __v,
 }
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
 clamp(_LIBCPP_LIFETIMEBOUND const _Tp& __v,
       _LIBCPP_LIFETIMEBOUND const _Tp& __lo,
       _LIBCPP_LIFETIMEBOUND const _Tp& __hi) {

diff --git a/libcxx/include/__algorithm/count.h b/libcxx/include/__algorithm/count.h
@@ -79,7 +79,7 @@ __count(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __l
 }
 
 template <class _InputIterator, class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __iter_diff_t<_InputIterator>
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __iter_diff_t<_InputIterator>
 count(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
   __identity __proj;
   return std::__count<_ClassicAlgPolicy>(__first, __last, __value, __proj);

diff --git a/libcxx/include/__algorithm/count_if.h b/libcxx/include/__algorithm/count_if.h
@@ -20,9 +20,9 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
-    typename iterator_traits<_InputIterator>::difference_type
-    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename iterator_traits<_InputIterator>::difference_type
+count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   typename iterator_traits<_InputIterator>::difference_type __r(0);
   for (; __first != __last; ++__first)
     if (__pred(*__first))

diff --git a/libcxx/include/__algorithm/equal.h b/libcxx/include/__algorithm/equal.h
@@ -55,14 +55,14 @@ __equal_iter_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _BinaryPredicate&)
 }
 
 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
   return std::__equal_iter_impl(
       std::__unwrap_iter(__first1), std::__unwrap_iter(__last1), std::__unwrap_iter(__first2), __pred);
 }
 
 template <class _InputIterator1, class _InputIterator2>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
   return std::equal(__first1, __last1, __first2, __equal_to());
 }
@@ -96,7 +96,7 @@ __equal_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _Up*, _Pred&, _Proj1&,
 }
 
 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 equal(_InputIterator1 __first1,
       _InputIterator1 __last1,
       _InputIterator2 __first2,
@@ -119,7 +119,7 @@ equal(_InputIterator1 __first1,
 }
 
 template <class _InputIterator1, class _InputIterator2>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
   return std::equal(__first1, __last1, __first2, __last2, __equal_to());
 }

diff --git a/libcxx/include/__algorithm/equal_range.h b/libcxx/include/__algorithm/equal_range.h
@@ -60,7 +60,7 @@ __equal_range(_Iter __first, _Sent __last, const _Tp& __value, _Compare&& __comp
 }
 
 template <class _ForwardIterator, class _Tp, class _Compare>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
+_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
   static_assert(__is_callable<_Compare, decltype(*__first), const _Tp&>::value, "The comparator has to be callable");
   static_assert(is_copy_constructible<_ForwardIterator>::value, "Iterator has to be copy constructible");
@@ -73,7 +73,7 @@ equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __valu
 }
 
 template <class _ForwardIterator, class _Tp>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
+_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
   return std::equal_range(std::move(__first), std::move(__last), __value, __less<>());
 }

diff --git a/libcxx/include/__algorithm/find.h b/libcxx/include/__algorithm/find.h
@@ -169,7 +169,7 @@ struct __find_segment {
 
 // public API
 template <class _InputIterator, class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
 find(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
   __identity __proj;
   return std::__rewrap_iter(

diff --git a/libcxx/include/__algorithm/find_end.h b/libcxx/include/__algorithm/find_end.h
@@ -205,7 +205,7 @@ _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Fo
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_end(
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_end(
     _ForwardIterator1 __first1,
     _ForwardIterator1 __last1,
     _ForwardIterator2 __first2,
@@ -215,7 +215,7 @@ _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1
 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
   return std::find_end(__first1, __last1, __first2, __last2, __equal_to());
 }

diff --git a/libcxx/include/__algorithm/find_first_of.h b/libcxx/include/__algorithm/find_first_of.h
@@ -35,7 +35,7 @@ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator1 __find_fir
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_first_of(
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_first_of(
     _ForwardIterator1 __first1,
     _ForwardIterator1 __last1,
     _ForwardIterator2 __first2,
@@ -45,7 +45,7 @@ _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_first_of(
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_first_of(
     _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
   return std::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to());
 }

diff --git a/libcxx/include/__algorithm/find_if.h b/libcxx/include/__algorithm/find_if.h
@@ -19,7 +19,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
 find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   for (; __first != __last; ++__first)
     if (__pred(*__first))

diff --git a/libcxx/include/__algorithm/find_if_not.h b/libcxx/include/__algorithm/find_if_not.h
@@ -19,7 +19,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
 find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   for (; __first != __last; ++__first)
     if (!__pred(*__first))

diff --git a/libcxx/include/__algorithm/fold.h b/libcxx/include/__algorithm/fold.h
@@ -78,8 +78,7 @@ concept __indirectly_binary_left_foldable =
 
 struct __fold_left_with_iter {
   template <input_iterator _Ip, sentinel_for<_Ip> _Sp, class _Tp, __indirectly_binary_left_foldable<_Tp, _Ip> _Fp>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto
-  operator()(_Ip __first, _Sp __last, _Tp __init, _Fp __f) {
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Ip __first, _Sp __last, _Tp __init, _Fp __f) {
     using _Up = decay_t<invoke_result_t<_Fp&, _Tp, iter_reference_t<_Ip>>>;
 
     if (__first == __last) {
@@ -95,7 +94,7 @@ struct __fold_left_with_iter {
   }
 
   template <input_range _Rp, class _Tp, __indirectly_binary_left_foldable<_Tp, iterator_t<_Rp>> _Fp>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Rp&& __r, _Tp __init, _Fp __f) {
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Rp&& __r, _Tp __init, _Fp __f) {
     auto __result = operator()(ranges::begin(__r), ranges::end(__r), std::move(__init), std::ref(__f));
 
     using _Up = decay_t<invoke_result_t<_Fp&, _Tp, range_reference_t<_Rp>>>;
@@ -107,13 +106,12 @@ inline constexpr auto fold_left_with_iter = __fold_left_with_iter();
 
 struct __fold_left {
   template <input_iterator _Ip, sentinel_for<_Ip> _Sp, class _Tp, __indirectly_binary_left_foldable<_Tp, _Ip> _Fp>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto
-  operator()(_Ip __first, _Sp __last, _Tp __init, _Fp __f) {
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Ip __first, _Sp __last, _Tp __init, _Fp __f) {
     return fold_left_with_iter(std::move(__first), std::move(__last), std::move(__init), std::ref(__f)).value;
   }
 
   template <input_range _Rp, class _Tp, __indirectly_binary_left_foldable<_Tp, iterator_t<_Rp>> _Fp>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Rp&& __r, _Tp __init, _Fp __f) {
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Rp&& __r, _Tp __init, _Fp __f) {
     return fold_left_with_iter(ranges::begin(__r), ranges::end(__r), std::move(__init), std::ref(__f)).value;
   }
 };

diff --git a/libcxx/include/__algorithm/includes.h b/libcxx/include/__algorithm/includes.h
@@ -47,7 +47,7 @@ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __includes(
 }
 
 template <class _InputIterator1, class _InputIterator2, class _Compare>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 includes(_InputIterator1 __first1,
          _InputIterator1 __last1,
          _InputIterator2 __first2,
@@ -67,7 +67,7 @@ includes(_InputIterator1 __first1,
 }
 
 template <class _InputIterator1, class _InputIterator2>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
   return std::includes(std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __less<>());
 }

diff --git a/libcxx/include/__algorithm/is_heap.h b/libcxx/include/__algorithm/is_heap.h
@@ -22,13 +22,13 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _RandomAccessIterator, class _Compare>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
   return std::__is_heap_until(__first, __last, static_cast<__comp_ref_type<_Compare> >(__comp)) == __last;
 }
 
 template <class _RandomAccessIterator>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
   return std::is_heap(__first, __last, __less<>());
 }

diff --git a/libcxx/include/__algorithm/is_heap_until.h b/libcxx/include/__algorithm/is_heap_until.h
@@ -46,13 +46,13 @@ __is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Co
 }
 
 template <class _RandomAccessIterator, class _Compare>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
   return std::__is_heap_until(__first, __last, static_cast<__comp_ref_type<_Compare> >(__comp));
 }
 
 template <class _RandomAccessIterator>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last) {
   return std::__is_heap_until(__first, __last, __less<>());
 }

diff --git a/libcxx/include/__algorithm/is_partitioned.h b/libcxx/include/__algorithm/is_partitioned.h
@@ -18,7 +18,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   for (; __first != __last; ++__first)
     if (!__pred(*__first))