diff --git a/libcxx/include/__math/rounding_functions.h b/libcxx/include/__math/rounding_functions.h
@@ -26,37 +26,35 @@ namespace __math {
 
 // ceil
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI float ceil(float __x) _NOEXCEPT { return __builtin_ceilf(__x); }
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI float ceil(float __x) _NOEXCEPT { return __builtin_ceilf(__x); }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI double ceil(double __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI double ceil(double __x) _NOEXCEPT {
   return __builtin_ceil(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long double ceil(long double __x) _NOEXCEPT {
-  return __builtin_ceill(__x);
-}
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI long double ceil(long double __x) _NOEXCEPT { return __builtin_ceill(__x); }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI double ceil(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI double ceil(_A1 __x) _NOEXCEPT {
   return __builtin_ceil((double)__x);
 }
 
 // floor
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI float floor(float __x) _NOEXCEPT { return __builtin_floorf(__x); }
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI float floor(float __x) _NOEXCEPT { return __builtin_floorf(__x); }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI double floor(double __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI double floor(double __x) _NOEXCEPT {
   return __builtin_floor(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long double floor(long double __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI long double floor(long double __x) _NOEXCEPT {
   return __builtin_floorl(__x);
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI double floor(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI double floor(_A1 __x) _NOEXCEPT {
   return __builtin_floor((double)__x);
 }
 
@@ -126,21 +124,19 @@ inline _LIBCPP_HIDE_FROM_ABI long lround(_A1 __x) _NOEXCEPT {
 
 // nearbyint
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI float nearbyint(float __x) _NOEXCEPT {
-  return __builtin_nearbyintf(__x);
-}
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI float nearbyint(float __x) _NOEXCEPT { return __builtin_nearbyintf(__x); }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI double nearbyint(double __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI double nearbyint(double __x) _NOEXCEPT {
   return __builtin_nearbyint(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long double nearbyint(long double __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI long double nearbyint(long double __x) _NOEXCEPT {
   return __builtin_nearbyintl(__x);
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI double nearbyint(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI double nearbyint(_A1 __x) _NOEXCEPT {
   return __builtin_nearbyint((double)__x);
 }
 
@@ -186,55 +182,53 @@ inline _LIBCPP_HIDE_FROM_ABI double nexttoward(_A1 __x, long double __y) _NOEXCE
 
 // rint
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI float rint(float __x) _NOEXCEPT { return __builtin_rintf(__x); }
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI float rint(float __x) _NOEXCEPT { return __builtin_rintf(__x); }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI double rint(double __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI double rint(double __x) _NOEXCEPT {
   return __builtin_rint(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long double rint(long double __x) _NOEXCEPT {
-  return __builtin_rintl(__x);
-}
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI long double rint(long double __x) _NOEXCEPT { return __builtin_rintl(__x); }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI double rint(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI double rint(_A1 __x) _NOEXCEPT {
   return __builtin_rint((double)__x);
 }
 
 // round
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI float round(float __x) _NOEXCEPT { return __builtin_round(__x); }
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI float round(float __x) _NOEXCEPT { return __builtin_round(__x); }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI double round(double __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI double round(double __x) _NOEXCEPT {
   return __builtin_round(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long double round(long double __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI long double round(long double __x) _NOEXCEPT {
   return __builtin_roundl(__x);
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI double round(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI double round(_A1 __x) _NOEXCEPT {
   return __builtin_round((double)__x);
 }
 
 // trunc
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI float trunc(float __x) _NOEXCEPT { return __builtin_trunc(__x); }
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI float trunc(float __x) _NOEXCEPT { return __builtin_trunc(__x); }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI double trunc(double __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI double trunc(double __x) _NOEXCEPT {
   return __builtin_trunc(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long double trunc(long double __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI long double trunc(long double __x) _NOEXCEPT {
   return __builtin_truncl(__x);
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI double trunc(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI double trunc(_A1 __x) _NOEXCEPT {
   return __builtin_trunc((double)__x);
 }
 

diff --git a/libcxx/include/__math/traits.h b/libcxx/include/__math/traits.h
@@ -29,142 +29,142 @@ namespace __math {
 // signbit
 
 template <class _A1, __enable_if_t<is_floating_point<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool signbit(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool signbit(_A1 __x) _NOEXCEPT {
   return __builtin_signbit(__x);
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value && is_signed<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool signbit(_A1 __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool signbit(_A1 __x) _NOEXCEPT {
   return __x < 0;
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value && !is_signed<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool signbit(_A1) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool signbit(_A1) _NOEXCEPT {
   return false;
 }
 
 // isfinite
 
 template <class _A1, __enable_if_t<is_arithmetic<_A1>::value && numeric_limits<_A1>::has_infinity, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(_A1 __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(_A1 __x) _NOEXCEPT {
   return __builtin_isfinite((typename __promote<_A1>::type)__x);
 }
 
 template <class _A1, __enable_if_t<is_arithmetic<_A1>::value && !numeric_limits<_A1>::has_infinity, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(_A1) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isfinite(_A1) _NOEXCEPT {
   return true;
 }
 
 // isinf
 
 template <class _A1, __enable_if_t<is_arithmetic<_A1>::value && numeric_limits<_A1>::has_infinity, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(_A1 __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(_A1 __x) _NOEXCEPT {
   return __builtin_isinf((typename __promote<_A1>::type)__x);
 }
 
 template <class _A1, __enable_if_t<is_arithmetic<_A1>::value && !numeric_limits<_A1>::has_infinity, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(_A1) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(_A1) _NOEXCEPT {
   return false;
 }
 
 #ifdef _LIBCPP_PREFERRED_OVERLOAD
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(float __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(float __x) _NOEXCEPT {
   return __builtin_isinf(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI _LIBCPP_PREFERRED_OVERLOAD bool
+[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI _LIBCPP_PREFERRED_OVERLOAD bool
 isinf(double __x) _NOEXCEPT {
   return __builtin_isinf(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(long double __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isinf(long double __x) _NOEXCEPT {
   return __builtin_isinf(__x);
 }
 #endif
 
 // isnan
 
 template <class _A1, __enable_if_t<is_floating_point<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(_A1 __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(_A1 __x) _NOEXCEPT {
   return __builtin_isnan(__x);
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(_A1) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(_A1) _NOEXCEPT {
   return false;
 }
 
 #ifdef _LIBCPP_PREFERRED_OVERLOAD
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(float __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(float __x) _NOEXCEPT {
   return __builtin_isnan(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI _LIBCPP_PREFERRED_OVERLOAD bool
+[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI _LIBCPP_PREFERRED_OVERLOAD bool
 isnan(double __x) _NOEXCEPT {
   return __builtin_isnan(__x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(long double __x) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnan(long double __x) _NOEXCEPT {
   return __builtin_isnan(__x);
 }
 #endif
 
 // isnormal
 
 template <class _A1, __enable_if_t<is_floating_point<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) _NOEXCEPT {
   return __builtin_isnormal(__x);
 }
 
 template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) _NOEXCEPT {
+[[nodiscard]] _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) _NOEXCEPT {
   return __x != 0;
 }
 
 // isgreater
 
 template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool isgreater(_A1 __x, _A2 __y) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isgreater(_A1 __x, _A2 __y) _NOEXCEPT {
   using type = typename __promote<_A1, _A2>::type;
   return __builtin_isgreater((type)__x, (type)__y);
 }
 
 // isgreaterequal
 
 template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool isgreaterequal(_A1 __x, _A2 __y) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isgreaterequal(_A1 __x, _A2 __y) _NOEXCEPT {
   using type = typename __promote<_A1, _A2>::type;
   return __builtin_isgreaterequal((type)__x, (type)__y);
 }
 
 // isless
 
 template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool isless(_A1 __x, _A2 __y) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isless(_A1 __x, _A2 __y) _NOEXCEPT {
   using type = typename __promote<_A1, _A2>::type;
   return __builtin_isless((type)__x, (type)__y);
 }
 
 // islessequal
 
 template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool islessequal(_A1 __x, _A2 __y) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool islessequal(_A1 __x, _A2 __y) _NOEXCEPT {
   using type = typename __promote<_A1, _A2>::type;
   return __builtin_islessequal((type)__x, (type)__y);
 }
 
 // islessgreater
 
 template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool islessgreater(_A1 __x, _A2 __y) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool islessgreater(_A1 __x, _A2 __y) _NOEXCEPT {
   using type = typename __promote<_A1, _A2>::type;
   return __builtin_islessgreater((type)__x, (type)__y);
 }
 
 // isunordered
 
 template <class _A1, class _A2, __enable_if_t<is_arithmetic<_A1>::value && is_arithmetic<_A2>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI bool isunordered(_A1 __x, _A2 __y) _NOEXCEPT {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI bool isunordered(_A1 __x, _A2 __y) _NOEXCEPT {
   using type = typename __promote<_A1, _A2>::type;
   return __builtin_isunordered((type)__x, (type)__y);
 }

diff --git a/libcxx/include/__memory/allocator.h b/libcxx/include/__memory/allocator.h
@@ -110,7 +110,7 @@ class _LIBCPP_TEMPLATE_VIS allocator : private __non_trivial_if<!is_void<_Tp>::v
   template <class _Up>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 allocator(const allocator<_Up>&) _NOEXCEPT {}
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp* allocate(size_t __n) {
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp* allocate(size_t __n) {
     if (__n > allocator_traits<allocator>::max_size(*this))
       __throw_bad_array_new_length();
     if (__libcpp_is_constant_evaluated()) {
@@ -153,7 +153,7 @@ class _LIBCPP_TEMPLATE_VIS allocator : private __non_trivial_if<!is_void<_Tp>::v
     return std::addressof(__x);
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DEPRECATED_IN_CXX17 _Tp*
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_DEPRECATED_IN_CXX17 _Tp*
   allocate(size_t __n, const void*) {
     return allocate(__n);
   }
@@ -190,7 +190,7 @@ class _LIBCPP_TEMPLATE_VIS allocator<const _Tp>
   template <class _Up>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 allocator(const allocator<_Up>&) _NOEXCEPT {}
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const _Tp* allocate(size_t __n) {
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const _Tp* allocate(size_t __n) {
     if (__n > allocator_traits<allocator>::max_size(*this))
       __throw_bad_array_new_length();
     if (__libcpp_is_constant_evaluated()) {
@@ -230,7 +230,7 @@ class _LIBCPP_TEMPLATE_VIS allocator<const _Tp>
     return std::addressof(__x);
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_DEPRECATED_IN_CXX17 const _Tp*
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_DEPRECATED_IN_CXX17 const _Tp*
   allocate(size_t __n, const void*) {
     return allocate(__n);
   }

diff --git a/libcxx/include/__memory/allocator_traits.h b/libcxx/include/__memory/allocator_traits.h
@@ -275,13 +275,13 @@ struct _LIBCPP_TEMPLATE_VIS allocator_traits {
   };
 #endif // _LIBCPP_CXX03_LANG
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
   allocate(allocator_type& __a, size_type __n) {
     return __a.allocate(__n);
   }
 
   template <class _Ap = _Alloc, __enable_if_t<__has_allocate_hint<_Ap, size_type, const_void_pointer>::value, int> = 0>
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
   allocate(allocator_type& __a, size_type __n, const_void_pointer __hint) {
     _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     return __a.allocate(__n, __hint);
@@ -290,7 +290,7 @@ struct _LIBCPP_TEMPLATE_VIS allocator_traits {
   template <class _Ap                                                                           = _Alloc,
             class                                                                               = void,
             __enable_if_t<!__has_allocate_hint<_Ap, size_type, const_void_pointer>::value, int> = 0>
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static pointer
   allocate(allocator_type& __a, size_type __n, const_void_pointer) {
     return __a.allocate(__n);
   }

diff --git a/libcxx/include/__memory/temporary_buffer.h b/libcxx/include/__memory/temporary_buffer.h
@@ -22,7 +22,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI _LIBCPP_DEPRECATED_IN_CXX17 pair<_Tp*, ptrdiff_t>
+_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI _LIBCPP_DEPRECATED_IN_CXX17 pair<_Tp*, ptrdiff_t>
 get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT {
   pair<_Tp*, ptrdiff_t> __r(0, 0);
   const ptrdiff_t __m =

diff --git a/libcxx/include/__memory_resource/memory_resource.h b/libcxx/include/__memory_resource/memory_resource.h
@@ -32,8 +32,8 @@ class _LIBCPP_AVAILABILITY_PMR _LIBCPP_EXPORTED_FROM_ABI memory_resource {
 public:
   virtual ~memory_resource();
 
-  _LIBCPP_NODISCARD_AFTER_CXX17
-  [[using __gnu__: __returns_nonnull__, __alloc_size__(2), __alloc_align__(3)]] _LIBCPP_HIDE_FROM_ABI void*
+  [[nodiscard]] [[using __gnu__: __returns_nonnull__, __alloc_size__(2), __alloc_align__(3)]]
+  _LIBCPP_HIDE_FROM_ABI void*
   allocate(size_t __bytes, size_t __align = __max_align) {
     return do_allocate(__bytes, __align);
   }

diff --git a/libcxx/include/__memory_resource/polymorphic_allocator.h b/libcxx/include/__memory_resource/polymorphic_allocator.h
@@ -60,7 +60,7 @@ class _LIBCPP_AVAILABILITY_PMR _LIBCPP_TEMPLATE_VIS polymorphic_allocator {
 
   // [mem.poly.allocator.mem]
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _ValueType* allocate(size_t __n) {
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI _ValueType* allocate(size_t __n) {
     if (__n > __max_size()) {
       __throw_bad_array_new_length();
     }

diff --git a/libcxx/include/__mutex/lock_guard.h b/libcxx/include/__mutex/lock_guard.h
@@ -29,13 +29,13 @@ class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable) loc
   mutex_type& __m_;
 
 public:
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI explicit lock_guard(mutex_type& __m)
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI explicit lock_guard(mutex_type& __m)
       _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
       : __m_(__m) {
     __m_.lock();
   }
 
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI lock_guard(mutex_type& __m, adopt_lock_t)
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI lock_guard(mutex_type& __m, adopt_lock_t)
       _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
       : __m_(__m) {}
   _LIBCPP_HIDE_FROM_ABI ~lock_guard() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) { __m_.unlock(); }

diff --git a/libcxx/include/__node_handle b/libcxx/include/__node_handle
@@ -147,7 +147,7 @@ public:
 
   _LIBCPP_HIDE_FROM_ABI explicit operator bool() const { return __ptr_ != nullptr; }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const { return __ptr_ == nullptr; }
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool empty() const { return __ptr_ == nullptr; }
 
   _LIBCPP_HIDE_FROM_ABI void swap(__basic_node_handle& __other) noexcept(
       __alloc_traits::propagate_on_container_swap::value || __alloc_traits::is_always_equal::value) {

diff --git a/libcxx/include/__ranges/as_rvalue_view.h b/libcxx/include/__ranges/as_rvalue_view.h
@@ -111,15 +111,15 @@ namespace views {
 namespace __as_rvalue {
 struct __fn : __range_adaptor_closure<__fn> {
   template <class _Range>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto
   operator()(_Range&& __range) noexcept(noexcept(as_rvalue_view(std::forward<_Range>(__range))))
       -> decltype(/*--------------------------*/ as_rvalue_view(std::forward<_Range>(__range))) {
     return /*---------------------------------*/ as_rvalue_view(std::forward<_Range>(__range));
   }
 
   template <class _Range>
     requires same_as<range_rvalue_reference_t<_Range>, range_reference_t<_Range>>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto
   operator()(_Range&& __range) noexcept(noexcept(views::all(std::forward<_Range>(__range))))
       -> decltype(/*--------------------------*/ views::all(std::forward<_Range>(__range))) {
     return /*---------------------------------*/ views::all(std::forward<_Range>(__range));

diff --git a/libcxx/include/__ranges/chunk_by_view.h b/libcxx/include/__ranges/chunk_by_view.h
@@ -205,15 +205,15 @@ namespace views {
 namespace __chunk_by {
 struct __fn {
   template <class _Range, class _Pred>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pred&& __pred) const
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Pred&& __pred) const
       noexcept(noexcept(/**/ chunk_by_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))))
           -> decltype(/*--*/ chunk_by_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred))) {
     return /*-------------*/ chunk_by_view(std::forward<_Range>(__range), std::forward<_Pred>(__pred));
   }
 
   template <class _Pred>
     requires constructible_from<decay_t<_Pred>, _Pred>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pred&& __pred) const
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pred&& __pred) const
       noexcept(is_nothrow_constructible_v<decay_t<_Pred>, _Pred>) {
     return __range_adaptor_closure_t(std::__bind_back(*this, std::forward<_Pred>(__pred)));
   }

diff --git a/libcxx/include/__ranges/drop_view.h b/libcxx/include/__ranges/drop_view.h
@@ -266,7 +266,7 @@ struct __fn {
             class _RawRange = remove_cvref_t<_Range>,
             class _Dist     = range_difference_t<_Range>>
     requires (__is_repeat_specialization<_RawRange> && sized_range<_RawRange>)
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Np&& __n) const
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Np&& __n) const
     noexcept(noexcept(views::repeat(*__range.__value_, ranges::distance(__range) - std::min<_Dist>(ranges::distance(__range), std::forward<_Np>(__n)))))
     -> decltype(      views::repeat(*__range.__value_, ranges::distance(__range) - std::min<_Dist>(ranges::distance(__range), std::forward<_Np>(__n))))
     { return          views::repeat(*__range.__value_, ranges::distance(__range) - std::min<_Dist>(ranges::distance(__range), std::forward<_Np>(__n))); }
@@ -277,7 +277,7 @@ struct __fn {
             class _RawRange = remove_cvref_t<_Range>,
             class _Dist     = range_difference_t<_Range>>
     requires (__is_repeat_specialization<_RawRange> && !sized_range<_RawRange>)
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
   constexpr auto operator()(_Range&& __range, _Np&&) const
     noexcept(noexcept(_LIBCPP_AUTO_CAST(std::forward<_Range>(__range))))
     -> decltype(      _LIBCPP_AUTO_CAST(std::forward<_Range>(__range)))

diff --git a/libcxx/include/__ranges/repeat_view.h b/libcxx/include/__ranges/repeat_view.h
@@ -229,13 +229,13 @@ namespace views {
 namespace __repeat {
 struct __fn {
   template <class _Tp>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Tp&& __value)
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Tp&& __value)
     noexcept(noexcept(ranges::repeat_view(std::forward<_Tp>(__value))))
     -> decltype(      ranges::repeat_view(std::forward<_Tp>(__value)))
     { return          ranges::repeat_view(std::forward<_Tp>(__value)); }
 
   template <class _Tp, class _Bound>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Tp&& __value, _Bound&& __bound_sentinel)
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI static constexpr auto operator()(_Tp&& __value, _Bound&& __bound_sentinel)
     noexcept(noexcept(ranges::repeat_view(std::forward<_Tp>(__value), std::forward<_Bound>(__bound_sentinel))))
     -> decltype(      ranges::repeat_view(std::forward<_Tp>(__value), std::forward<_Bound>(__bound_sentinel)))
     { return          ranges::repeat_view(std::forward<_Tp>(__value), std::forward<_Bound>(__bound_sentinel)); }

diff --git a/libcxx/include/__ranges/split_view.h b/libcxx/include/__ranges/split_view.h
@@ -200,7 +200,7 @@ namespace __split_view {
 struct __fn {
   // clang-format off
   template <class _Range, class _Pattern>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
   constexpr auto operator()(_Range&& __range, _Pattern&& __pattern) const
     noexcept(noexcept(split_view(std::forward<_Range>(__range), std::forward<_Pattern>(__pattern))))
     -> decltype(      split_view(std::forward<_Range>(__range), std::forward<_Pattern>(__pattern)))
@@ -209,7 +209,7 @@ struct __fn {
 
   template <class _Pattern>
     requires constructible_from<decay_t<_Pattern>, _Pattern>
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pattern&& __pattern) const
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Pattern&& __pattern) const
       noexcept(is_nothrow_constructible_v<decay_t<_Pattern>, _Pattern>) {
     return __range_adaptor_closure_t(std::__bind_back(*this, std::forward<_Pattern>(__pattern)));
   }

diff --git a/libcxx/include/__ranges/take_view.h b/libcxx/include/__ranges/take_view.h
@@ -308,7 +308,7 @@ struct __fn {
             class _RawRange = remove_cvref_t<_Range>,
             class _Dist     = range_difference_t<_Range>>
     requires(__is_repeat_specialization<_RawRange> && sized_range<_RawRange>)
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Np&& __n) const
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Np&& __n) const
     noexcept(noexcept(views::repeat(*__range.__value_, std::min<_Dist>(ranges::distance(__range), std::forward<_Np>(__n)))))
     -> decltype(      views::repeat(*__range.__value_, std::min<_Dist>(ranges::distance(__range), std::forward<_Np>(__n))))
     { return          views::repeat(*__range.__value_, std::min<_Dist>(ranges::distance(__range), std::forward<_Np>(__n))); }
@@ -319,7 +319,7 @@ struct __fn {
             class _RawRange = remove_cvref_t<_Range>,
             class _Dist     = range_difference_t<_Range>>
     requires(__is_repeat_specialization<_RawRange> && !sized_range<_RawRange>)
-  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Np&& __n) const
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, _Np&& __n) const
     noexcept(noexcept(views::repeat(*__range.__value_, static_cast<_Dist>(__n))))
     -> decltype(      views::repeat(*__range.__value_, static_cast<_Dist>(__n)))
     { return          views::repeat(*__range.__value_, static_cast<_Dist>(__n)); }

diff --git a/libcxx/include/__ranges/to.h b/libcxx/include/__ranges/to.h
@@ -85,7 +85,7 @@ concept __always_false = false;
 // `ranges::to` base template -- the `_Container` type is a simple type template parameter.
 template <class _Container, input_range _Range, class... _Args>
   requires(!view<_Container>)
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr _Container to(_Range&& __range, _Args&&... __args) {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Container to(_Range&& __range, _Args&&... __args) {
   // Mandates: C is a cv-unqualified class type.
   static_assert(!is_const_v<_Container>, "The target container cannot be const-qualified, please remove the const");
   static_assert(
@@ -192,7 +192,7 @@ struct _Deducer {
 // `ranges::to` specialization -- `_Container` is a template template parameter requiring deduction to figure out the
 // container element type.
 template <template <class...> class _Container, input_range _Range, class... _Args>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Range&& __range, _Args&&... __args) {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Range&& __range, _Args&&... __args) {
   using _DeduceExpr = typename _Deducer<_Container, _Range, _Args...>::type;
   return ranges::to<_DeduceExpr>(std::forward<_Range>(__range), std::forward<_Args>(__args)...);
 }
@@ -201,7 +201,7 @@ _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Range&& __range,
 // parameter.
 template <class _Container, class... _Args>
   requires(!view<_Container>)
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Args&&... __args) {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Args&&... __args) {
   // Mandates: C is a cv-unqualified class type.
   static_assert(!is_const_v<_Container>, "The target container cannot be const-qualified, please remove the const");
   static_assert(
@@ -219,7 +219,7 @@ _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Args&&... __args)
 // Range adaptor closure object 2 -- wrapping the `ranges::to` version where `_Container` is a template template
 // parameter.
 template <template <class...> class _Container, class... _Args>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Args&&... __args) {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto to(_Args&&... __args) {
   // clang-format off
   auto __to_func = []<input_range _Range, class... _Tail,
                       class _DeducedExpr = typename _Deducer<_Container, _Range, _Tail...>::type>

diff --git a/libcxx/include/__utility/as_const.h b/libcxx/include/__utility/as_const.h
@@ -22,7 +22,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept {
   return __t;
 }
 

diff --git a/libcxx/include/__utility/forward.h b/libcxx/include/__utility/forward.h
@@ -21,13 +21,13 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp&&
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp&&
 forward(_LIBCPP_LIFETIMEBOUND __libcpp_remove_reference_t<_Tp>& __t) _NOEXCEPT {
   return static_cast<_Tp&&>(__t);
 }
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp&&
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp&&
 forward(_LIBCPP_LIFETIMEBOUND __libcpp_remove_reference_t<_Tp>&& __t) _NOEXCEPT {
   static_assert(!is_lvalue_reference<_Tp>::value, "cannot forward an rvalue as an lvalue");
   return static_cast<_Tp&&>(__t);

diff --git a/libcxx/include/__utility/move.h b/libcxx/include/__utility/move.h
@@ -26,7 +26,7 @@ _LIBCPP_PUSH_MACROS
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __libcpp_remove_reference_t<_Tp>&&
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __libcpp_remove_reference_t<_Tp>&&
 move(_LIBCPP_LIFETIMEBOUND _Tp&& __t) _NOEXCEPT {
   typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tp> _Up;
   return static_cast<_Up&&>(__t);
@@ -37,7 +37,7 @@ using __move_if_noexcept_result_t =
     __conditional_t<!is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value, const _Tp&, _Tp&&>;
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __move_if_noexcept_result_t<_Tp>
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __move_if_noexcept_result_t<_Tp>
 move_if_noexcept(_LIBCPP_LIFETIMEBOUND _Tp& __x) _NOEXCEPT {
   return std::move(__x);
 }

diff --git a/libcxx/include/__utility/to_underlying.h b/libcxx/include/__utility/to_underlying.h
@@ -28,7 +28,7 @@ _LIBCPP_HIDE_FROM_ABI constexpr typename underlying_type<_Tp>::type __to_underly
 
 #if _LIBCPP_STD_VER >= 23
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr underlying_type_t<_Tp> to_underlying(_Tp __val) noexcept {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr underlying_type_t<_Tp> to_underlying(_Tp __val) noexcept {
   return std::__to_underlying(__val);
 }
 #endif

diff --git a/libcxx/include/array b/libcxx/include/array
@@ -230,7 +230,7 @@ struct _LIBCPP_TEMPLATE_VIS array {
   // capacity:
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT { return _Size; }
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT { return _Size; }
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {
     return _Size == 0;
   }
 
@@ -335,7 +335,7 @@ struct _LIBCPP_TEMPLATE_VIS array<_Tp, 0> {
   // capacity:
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT { return 0; }
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT { return 0; }
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT { return true; }
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT { return true; }
 
   // element access:
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator[](size_type) _NOEXCEPT {

diff --git a/libcxx/include/cstddef b/libcxx/include/cstddef
@@ -122,7 +122,7 @@ _LIBCPP_HIDE_FROM_ABI constexpr byte operator>>(byte __lhs, _Integer __shift) no
 }
 
 template <class _Integer, __enable_if_t<is_integral<_Integer>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr _Integer to_integer(byte __b) noexcept {
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Integer to_integer(byte __b) noexcept {
   return static_cast<_Integer>(__b);
 }
 

diff --git a/libcxx/include/deque b/libcxx/include/deque
@@ -707,7 +707,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI void resize(size_type __n);
   _LIBCPP_HIDE_FROM_ABI void resize(size_type __n, const value_type& __v);
   _LIBCPP_HIDE_FROM_ABI void shrink_to_fit() _NOEXCEPT;
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return size() == 0; }
 
   // element access:
   _LIBCPP_HIDE_FROM_ABI reference operator[](size_type __i) _NOEXCEPT;

diff --git a/libcxx/include/forward_list b/libcxx/include/forward_list
@@ -761,7 +761,7 @@ public:
     return const_iterator(base::__before_begin());
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT {
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT {
     return base::__before_begin()->__next_ == nullptr;
   }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {

diff --git a/libcxx/include/future b/libcxx/include/future
@@ -1842,9 +1842,8 @@ inline _LIBCPP_HIDE_FROM_ABI bool __does_policy_contain(launch __policy, launch
 }
 
 template <class _Fp, class... _Args>
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI
-    future<typename __invoke_of<__decay_t<_Fp>, __decay_t<_Args>...>::type>
-    async(launch __policy, _Fp&& __f, _Args&&... __args) {
+[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI future<typename __invoke_of<__decay_t<_Fp>, __decay_t<_Args>...>::type>
+async(launch __policy, _Fp&& __f, _Args&&... __args) {
   typedef __async_func<__decay_t<_Fp>, __decay_t<_Args>...> _BF;
   typedef typename _BF::_Rp _Rp;
 
@@ -1868,9 +1867,8 @@ _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI
 }
 
 template <class _Fp, class... _Args>
-_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_HIDE_FROM_ABI
-    future<typename __invoke_of<__decay_t<_Fp>, __decay_t<_Args>...>::type>
-    async(_Fp&& __f, _Args&&... __args) {
+[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI future<typename __invoke_of<__decay_t<_Fp>, __decay_t<_Args>...>::type>
+async(_Fp&& __f, _Args&&... __args) {
   return std::async(launch::any, std::forward<_Fp>(__f), std::forward<_Args>(__args)...);
 }
 

diff --git a/libcxx/include/limits b/libcxx/include/limits
diff --git a/libcxx/include/list b/libcxx/include/list
@@ -760,7 +760,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT;
 
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return base::__sz(); }
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return base::empty(); }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return base::empty(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
     return std::min<size_type>(base::__node_alloc_max_size(), numeric_limits<difference_type >::max());
   }

diff --git a/libcxx/include/map b/libcxx/include/map
@@ -1149,7 +1149,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return rbegin(); }
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __tree_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __tree_.max_size(); }
 
@@ -1838,7 +1838,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return rbegin(); }
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __tree_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __tree_.max_size(); }
 

diff --git a/libcxx/include/math.h b/libcxx/include/math.h
@@ -388,22 +388,22 @@ namespace __math {
 
 // template on non-double overloads to make them weaker than same overloads from MSVC runtime
 template <class = int>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI int fpclassify(float __x) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI int fpclassify(float __x) _NOEXCEPT {
   return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL, FP_SUBNORMAL, FP_ZERO, __x);
 }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI int fpclassify(double __x) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI int fpclassify(double __x) _NOEXCEPT {
   return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL, FP_SUBNORMAL, FP_ZERO, __x);
 }
 
 template <class = int>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI int fpclassify(long double __x) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI int fpclassify(long double __x) _NOEXCEPT {
   return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL, FP_SUBNORMAL, FP_ZERO, __x);
 }
 
 template <class _A1, std::__enable_if_t<std::is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI int fpclassify(_A1 __x) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI int fpclassify(_A1 __x) _NOEXCEPT {
   return __x == 0 ? FP_ZERO : FP_NORMAL;
 }
 

diff --git a/libcxx/include/new b/libcxx/include/new
@@ -204,17 +204,17 @@ inline constexpr destroying_delete_t destroying_delete{};
 
 #if !defined(_LIBCPP_ABI_VCRUNTIME)
 
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz) _THROW_BAD_ALLOC;
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void*
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz) _THROW_BAD_ALLOC;
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void*
 operator new(std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p) _NOEXCEPT;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, const std::nothrow_t&) _NOEXCEPT;
 #  ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::size_t __sz) _NOEXCEPT;
 #  endif
 
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz) _THROW_BAD_ALLOC;
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void*
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz) _THROW_BAD_ALLOC;
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void*
 operator new[](std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p) _NOEXCEPT;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
@@ -223,19 +223,19 @@ _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::size_t __sz)
 #  endif
 
 #  ifndef _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void*
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void*
 operator new(std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void*
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void*
 operator new(std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::align_val_t) _NOEXCEPT;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
 #    ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete(void* __p, std::size_t __sz, std::align_val_t) _NOEXCEPT;
 #    endif
 
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void*
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void*
 operator new[](std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
-_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void*
+_LIBCPP_NODISCARD _LIBCPP_OVERRIDABLE_FUNC_VIS void*
 operator new[](std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::align_val_t) _NOEXCEPT;
 _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
@@ -244,10 +244,10 @@ _LIBCPP_OVERRIDABLE_FUNC_VIS void operator delete[](void* __p, std::size_t __sz,
 #    endif
 #  endif
 
-_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_HIDE_FROM_ABI void* operator new(std::size_t, void* __p) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI void* operator new(std::size_t, void* __p) _NOEXCEPT {
   return __p;
 }
-_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_HIDE_FROM_ABI void* operator new[](std::size_t, void* __p) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI void* operator new[](std::size_t, void* __p) _NOEXCEPT {
   return __p;
 }
 inline _LIBCPP_HIDE_FROM_ABI void operator delete(void*, void*) _NOEXCEPT {}
@@ -334,15 +334,15 @@ inline _LIBCPP_HIDE_FROM_ABI void __libcpp_deallocate_unsized(void* __ptr, size_
 }
 
 template <class _Tp>
-_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp* __launder(_Tp* __p) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp* __launder(_Tp* __p) _NOEXCEPT {
   static_assert(!(is_function<_Tp>::value), "can't launder functions");
   static_assert(!(is_same<void, __remove_cv_t<_Tp> >::value), "can't launder cv-void");
   return __builtin_launder(__p);
 }
 
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp>
-_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp* launder(_Tp* __p) noexcept {
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp* launder(_Tp* __p) noexcept {
   return std::__launder(__p);
 }
 #endif

diff --git a/libcxx/include/queue b/libcxx/include/queue
@@ -372,7 +372,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI queue(queue&& __q, const _Alloc& __a) : c(std::move(__q.c), __a) {}
 #endif // _LIBCPP_CXX03_LANG
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
   _LIBCPP_HIDE_FROM_ABI size_type size() const { return c.size(); }
 
   _LIBCPP_HIDE_FROM_ABI reference front() { return c.front(); }
@@ -649,7 +649,7 @@ public:
 
 #endif
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
   _LIBCPP_HIDE_FROM_ABI size_type size() const { return c.size(); }
   _LIBCPP_HIDE_FROM_ABI const_reference top() const { return c.front(); }
 

diff --git a/libcxx/include/regex b/libcxx/include/regex
@@ -4583,7 +4583,7 @@ public:
   // size:
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __matches_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __matches_.max_size(); }
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return size() == 0; }
 
   // element access:
   _LIBCPP_HIDE_FROM_ABI difference_type length(size_type __sub = 0) const {

diff --git a/libcxx/include/scoped_allocator b/libcxx/include/scoped_allocator
@@ -389,10 +389,10 @@ public:
     return _Base::outer_allocator();
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI pointer allocate(size_type __n) {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pointer allocate(size_type __n) {
     return allocator_traits<outer_allocator_type>::allocate(outer_allocator(), __n);
   }
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI pointer allocate(size_type __n, const_void_pointer __hint) {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pointer allocate(size_type __n, const_void_pointer __hint) {
     return allocator_traits<outer_allocator_type>::allocate(outer_allocator(), __n, __hint);
   }
 

diff --git a/libcxx/include/set b/libcxx/include/set
@@ -716,7 +716,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return rbegin(); }
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __tree_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __tree_.max_size(); }
 
@@ -1176,7 +1176,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return rbegin(); }
   _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __tree_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __tree_.max_size(); }
 

diff --git a/libcxx/include/stack b/libcxx/include/stack
@@ -231,7 +231,7 @@ public:
 
 #endif
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
   _LIBCPP_HIDE_FROM_ABI size_type size() const { return c.size(); }
   _LIBCPP_HIDE_FROM_ABI reference top() { return c.back(); }
   _LIBCPP_HIDE_FROM_ABI const_reference top() const { return c.back(); }

diff --git a/libcxx/include/stdlib.h b/libcxx/include/stdlib.h
@@ -110,21 +110,19 @@ extern "C++" {
 
 // MSVCRT already has the correct prototype in <stdlib.h> if __cplusplus is defined
 #    if !defined(_LIBCPP_MSVCRT)
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long abs(long __x) _NOEXCEPT { return __builtin_labs(__x); }
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long long abs(long long __x) _NOEXCEPT {
-  return __builtin_llabs(__x);
-}
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI long abs(long __x) _NOEXCEPT { return __builtin_labs(__x); }
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI long long abs(long long __x) _NOEXCEPT { return __builtin_llabs(__x); }
 #    endif // !defined(_LIBCPP_MSVCRT)
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI float abs(float __lcpp_x) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI float abs(float __lcpp_x) _NOEXCEPT {
   return __builtin_fabsf(__lcpp_x); // Use builtins to prevent needing math.h
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI double abs(double __lcpp_x) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI double abs(double __lcpp_x) _NOEXCEPT {
   return __builtin_fabs(__lcpp_x);
 }
 
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI long double abs(long double __lcpp_x) _NOEXCEPT {
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI long double abs(long double __lcpp_x) _NOEXCEPT {
   return __builtin_fabsl(__lcpp_x);
 }
 

diff --git a/libcxx/include/string b/libcxx/include/string
@@ -1233,7 +1233,7 @@ public:
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void shrink_to_fit() _NOEXCEPT;
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void clear() _NOEXCEPT;
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool empty() const _NOEXCEPT {
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool empty() const _NOEXCEPT {
     return size() == 0;
   }
 

diff --git a/libcxx/include/string_view b/libcxx/include/string_view
@@ -394,7 +394,7 @@ public:
     return numeric_limits<size_type>::max() / sizeof(value_type);
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {
     return __size_ == 0;
   }
 

diff --git a/libcxx/include/unordered_map b/libcxx/include/unordered_map
@@ -1207,7 +1207,7 @@ public:
     return allocator_type(__table_.__node_alloc());
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
 
@@ -2015,7 +2015,7 @@ public:
     return allocator_type(__table_.__node_alloc());
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
 

diff --git a/libcxx/include/unordered_set b/libcxx/include/unordered_set
@@ -735,7 +735,7 @@ public:
     return allocator_type(__table_.__node_alloc());
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
 
@@ -1335,7 +1335,7 @@ public:
     return allocator_type(__table_.__node_alloc());
   }
 
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
   _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
   _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
 

diff --git a/libcxx/include/vector b/libcxx/include/vector
@@ -598,7 +598,7 @@ public:
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type capacity() const _NOEXCEPT {
     return static_cast<size_type>(__end_cap() - this->__begin_);
   }
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT {
+  _LIBCPP_NODISCARD _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT {
     return this->__begin_ == this->__end_;
   }
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT;
@@ -2006,7 +2006,7 @@ public:
     return __internal_cap_to_external(__cap());
   }
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type size() const _NOEXCEPT { return __size_; }
-  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool empty() const _NOEXCEPT {
+  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool empty() const _NOEXCEPT {
     return __size_ == 0;
   }
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void reserve(size_type __n);

diff --git a/libcxx/src/tzdb.cpp b/libcxx/src/tzdb.cpp
@@ -637,7 +637,7 @@ void __init_tzdb(tzdb& __tzdb, __tz::__rules_storage_type& __rules) {
 //                           Public API
 //===----------------------------------------------------------------------===//
 
-_LIBCPP_NODISCARD_EXT _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI tzdb_list& get_tzdb_list() {
+_LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI tzdb_list& get_tzdb_list() {
   static tzdb_list __result{new tzdb_list::__impl()};
   return __result;
 }
@@ -649,7 +649,7 @@ _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI const tzdb& reload_tzdb() {
   return chrono::get_tzdb_list().__implementation().__load();
 }
 
-_LIBCPP_NODISCARD_EXT _LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI string remote_version() {
+_LIBCPP_AVAILABILITY_TZDB _LIBCPP_EXPORTED_FROM_ABI string remote_version() {
   filesystem::path __root = chrono::__libcpp_tzdb_directory();
   ifstream __tzdata{__root / "tzdata.zi"};
   return chrono::__parse_version(__tzdata);

diff --git a/...agnostics/nodiscard_extensions.verify.cpp → ...iagnostics/algorithm.nodiscard.verify.cpp b/...agnostics/nodiscard_extensions.verify.cpp → ...iagnostics/algorithm.nodiscard.verify.cpp
@@ -8,30 +8,16 @@
 
 // UNSUPPORTED: c++03
 
-// Test that entities declared [[nodiscard]] as an extension by libc++, are
-// actually declared as such when _LIBCPP_DISABLE_NODISCARD_EXT is not specified.
-
-// All entities to which libc++ applies [[nodiscard]] as an extension should
-// be tested here and in nodiscard_extensions.pass.cpp. They should also
-// be listed in `UsingLibcxx.rst` in the documentation for the extension.
-
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+// check that <algorithm> functions are marked [[nodiscard]]
 
 #include <algorithm>
-#include <bit> // bit_cast
-#include <cstddef> // to_integer
-#include <functional> // identity
-#include <iterator>
-#include <memory>
-#include <utility> // to_underlying
-
-#include "test_macros.h"
+#include <functional>
 
 struct P {
   bool operator()(int) const { return false; }
 };
 
-void test_algorithms() {
+void test() {
   int arr[1] = { 1 };
 
   // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
@@ -297,57 +283,100 @@ void test_algorithms() {
 
   // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::upper_bound(std::begin(arr), std::end(arr), 1, std::greater<int>());
-}
-
-template<class LV, class RV>
-void test_template_cast_wrappers(LV&& lv, RV&& rv) {
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::forward<LV>(lv);
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::forward<RV>(rv);
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::move(lv);
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::move(rv);
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::move_if_noexcept(lv);
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::move_if_noexcept(rv);
-
-#if TEST_STD_VER >= 17
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::as_const(lv);
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::as_const(rv);
-#endif
 
 #if TEST_STD_VER >= 20
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::identity()(lv);
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::identity()(rv);
+  int range[1];
+  int* iter = range;
+  auto pred = [](auto...) { return true; };
+  std::ranges::adjacent_find(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::adjacent_find(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::all_of(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::all_of(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::any_of(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::any_of(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::binary_search(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::binary_search(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::clamp(1, 2, 3); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::count_if(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::count_if(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::count(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::count(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::equal_range(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::equal_range(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::equal(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::equal(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_end(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_end(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_first_of(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_first_of(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_if_not(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_if_not(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_if(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_if(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::includes(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::includes(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_heap_until(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_heap_until(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_heap(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_heap(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_partitioned(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_partitioned(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_permutation(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_permutation(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_sorted_until(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_sorted_until(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_sorted(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::is_sorted(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::lexicographical_compare(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::lexicographical_compare(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::lower_bound(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::lower_bound(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::max_element(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::max_element(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::max(1, 2); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::max({1, 2, 3}); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::max(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::minmax_element(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::minmax_element(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::minmax(1, 2); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::minmax({1, 2, 3}); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::minmax(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::mismatch(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::mismatch(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::none_of(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::none_of(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::remove_if(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::remove_if(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::remove(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::remove(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::search_n(range, 1, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::search_n(iter, iter, 1, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::search(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::search(iter, iter, iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::unique(range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::unique(iter, iter); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::upper_bound(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::upper_bound(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
 #endif
-}
 
-void test_nontemplate_cast_wrappers()
-{
-#if TEST_STD_VER > 14
-  std::byte b{42};
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::to_integer<int>(b);
+#if TEST_STD_VER >= 23
+  std::ranges::contains(range, 1);
+  // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::contains(iter, iter, 1);
+  // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::contains_subrange(range, range);
+  // expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::contains_subrange(iter, iter, iter, iter);
+  // expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::fold_left(range, 0, std::plus());
+  // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::fold_left(iter, iter, 0, std::plus());
+  // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::fold_left_with_iter(range, 0, std::plus());
+  // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::fold_left_with_iter(iter, iter, 0, std::plus());
+  // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
 #endif
-
-#if TEST_STD_VER > 20
-  enum E { Apple, Orange } e = Apple;
-  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
-  std::to_underlying(e);
-#endif
-}
-
-void f() {
-  test_algorithms();
-
-  int i = 42;
-  test_template_cast_wrappers(i, std::move(i));
-  test_nontemplate_cast_wrappers();
 }
diff --git a/libcxx/test/libcxx/diagnostics/array.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/array.nodiscard.verify.cpp
@@ -0,0 +1,23 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <array> functions are marked [[nodiscard]]
+
+#include <array>
+
+void array_test() {
+  std::array<int, 1> array;
+  array.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
+
+void empty_array_test() {
+  std::array<int, 0> array;
+  array.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/...stics/bit.nodiscard_extensions.verify.cpp → ...bcxx/diagnostics/bit.nodiscard.verify.cpp b/...stics/bit.nodiscard_extensions.verify.cpp → ...bcxx/diagnostics/bit.nodiscard.verify.cpp
diff --git a/libcxx/test/libcxx/diagnostics/bit.nodiscard_extensions.compile.pass.cpp b/libcxx/test/libcxx/diagnostics/bit.nodiscard_extensions.compile.pass.cpp
diff --git a/...cs/chrono.nodiscard_extensions.verify.cpp → ...x/diagnostics/chrono.nodiscard.verify.cpp b/...cs/chrono.nodiscard_extensions.verify.cpp → ...x/diagnostics/chrono.nodiscard.verify.cpp
diff --git a/libcxx/test/libcxx/diagnostics/chrono.nodiscard_extensions.compile.pass.cpp b/libcxx/test/libcxx/diagnostics/chrono.nodiscard_extensions.compile.pass.cpp
diff --git a/...tics/math_nodiscard_extensions.verify.cpp → ...xx/diagnostics/cmath.nodiscard.verify.cpp b/...tics/math_nodiscard_extensions.verify.cpp → ...xx/diagnostics/cmath.nodiscard.verify.cpp
diff --git a/...agnostics/nodiscard_aftercxx17.verify.cpp → .../diagnostics/cstddef.nodiscard.verify.cpp b/...agnostics/nodiscard_aftercxx17.verify.cpp → .../diagnostics/cstddef.nodiscard.verify.cpp
@@ -6,16 +6,17 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Test that _LIBCPP_NODISCARD_AFTER_CXX17 works
-// #define _LIBCPP_NODISCARD_AFTER_CXX17 [[nodiscard]]
-
 // UNSUPPORTED: c++03
-// UNSUPPORTED: (c++11 || c++14 || c++17) && !stdlib=libc++
 
-#include <__config>
+// check that <cstddef> functions are marked [[nodiscard]]
+
+#include <cstddef>
 
-_LIBCPP_NODISCARD_AFTER_CXX17 int foo() { return 6; }
+#include "test_macros.h"
 
-void f() {
-    foo(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+void test() {
+#if TEST_STD_VER >= 17
+  std::byte b{42};
+  std::to_integer<int>(b); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
 }
diff --git a/libcxx/test/libcxx/diagnostics/cstdlib.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/cstdlib.nodiscard.verify.cpp
@@ -0,0 +1,22 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <cstdlib> functions are marked [[nodiscard]]
+
+#include <cmath>
+#include "test_macros.h"
+
+void test() {
+  std::abs(0l); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::abs(0ll); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::abs(0.f); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::abs(0.); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::abs(0.l); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/libcxx/test/libcxx/diagnostics/deque.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/deque.nodiscard.verify.cpp
@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <deque> functions are marked [[nodiscard]]
+
+#include <deque>
+
+void test() {
+  std::deque<int> deque;
+  deque.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/libcxx/test/libcxx/diagnostics/filesystem.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/filesystem.nodiscard.verify.cpp
@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <filesystem> functions are marked [[nodiscard]]
+
+#include <filesystem>
+
+void test() {
+  std::filesystem::path path;
+  path.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/...cs/format.nodiscard_extensions.verify.cpp → ...x/diagnostics/format.nodiscard.verify.cpp b/...cs/format.nodiscard_extensions.verify.cpp → ...x/diagnostics/format.nodiscard.verify.cpp
diff --git a/libcxx/test/libcxx/diagnostics/format.nodiscard_extensions.compile.pass.cpp b/libcxx/test/libcxx/diagnostics/format.nodiscard_extensions.compile.pass.cpp
diff --git a/libcxx/test/libcxx/diagnostics/forward_list.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/forward_list.nodiscard.verify.cpp
@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <forward_list> functions are marked [[nodiscard]]
+
+#include <forward_list>
+
+void test() {
+  std::forward_list<int> forward_list;
+  forward_list.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/.../ptr.launder/launder.nodiscard.verify.cpp → ...agnostics/functional.nodiscard.verify.cpp b/.../ptr.launder/launder.nodiscard.verify.cpp → ...agnostics/functional.nodiscard.verify.cpp
@@ -6,16 +6,17 @@
 //
 //===----------------------------------------------------------------------===//
 
-// <new>
+// UNSUPPORTED: c++03
 
-// template <class T> constexpr T* launder(T* p) noexcept;
+// check that <functional> functions are marked [[nodiscard]]
 
-// UNSUPPORTED: c++03, c++11, c++14
-// UNSUPPORTED: c++17 && !stdlib=libc++
+#include <functional>
 
-#include <new>
+#include "test_macros.h"
 
-void f() {
-    int *p = nullptr;
-    std::launder(p); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+void test() {
+  int i = 0;
+#if TEST_STD_VER >= 20
+  std::identity()(i); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
 }
diff --git a/libcxx/test/libcxx/diagnostics/future.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/future.nodiscard.verify.cpp
@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <future> functions are marked [[nodiscard]]
+
+#include <future>
+
+void test() {
+  std::async([]() {}); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::async(std::launch::any, []() {}); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/libcxx/test/libcxx/diagnostics/iterator.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/iterator.nodiscard.verify.cpp
@@ -0,0 +1,24 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <iterator> functions are marked [[nodiscard]]
+
+#include <iterator>
+#include <vector>
+
+void test() {
+  std::vector<int> container;
+  int c_array[] = {1, 2, 3};
+  std::initializer_list<int> initializer_list;
+
+  std::empty(container);        // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::empty(c_array);          // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::empty(initializer_list); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/...cs/limits.nodiscard_extensions.verify.cpp → ...x/diagnostics/limits.nodiscard.verify.cpp b/...cs/limits.nodiscard_extensions.verify.cpp → ...x/diagnostics/limits.nodiscard.verify.cpp
diff --git a/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.compile.pass.cpp b/libcxx/test/libcxx/diagnostics/limits.nodiscard_extensions.compile.pass.cpp
diff --git a/libcxx/test/libcxx/diagnostics/list.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/list.nodiscard.verify.cpp
@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <list> functions are marked [[nodiscard]]
+
+#include <list>
+
+void test() {
+  std::list<int> list;
+  list.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/libcxx/test/libcxx/diagnostics/map.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/map.nodiscard.verify.cpp
@@ -0,0 +1,23 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <map> functions are marked [[nodiscard]]
+
+#include <map>
+
+void map_test() {
+  std::map<int, int> map;
+  map.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
+
+void multimap_test() {
+  std::multimap<int, int> multimap;
+  multimap.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/libcxx/test/libcxx/diagnostics/memory.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/memory.nodiscard.verify.cpp
@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <memory> functions are marked [[nodiscard]]
+
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
+#include <memory>
+
+#include "test_macros.h"
+
+void test() {
+  std::get_temporary_buffer<int>(0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
+
+void test_allocator_traits() {
+  std::allocator<int> allocator;
+  std::allocator_traits<std::allocator<int>> allocator_traits;
+  allocator_traits.allocate(allocator, 1);          // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  allocator_traits.allocate(allocator, 1, nullptr); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
+
+void test_allocator() {
+  std::allocator<int> allocator;
+  allocator.allocate(1);          // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#if TEST_STD_VER <= 17
+  allocator.allocate(1, nullptr); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
+#if TEST_STD_VER >= 23
+  allocator.allocate_at_least(1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
+}
+
+void test_const_allocator() {
+  std::allocator<const int> allocator;
+  allocator.allocate(1);          // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+#if TEST_STD_VER <= 17
+  allocator.allocate(1, nullptr); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
+#if TEST_STD_VER >= 23
+  allocator.allocate_at_least(1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
+}
diff --git a/libcxx/test/libcxx/diagnostics/memory_resource.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/memory_resource.nodiscard.verify.cpp
@@ -0,0 +1,23 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// check that <memory_resource> functions are marked [[nodiscard]]
+
+#include <memory_resource>
+
+#include "test_macros.h"
+
+void test() {
+  std::pmr::memory_resource* resource = std::pmr::null_memory_resource();
+  resource->allocate(1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  std::pmr::polymorphic_allocator<int> polymorphic_allocator;
+  polymorphic_allocator.allocate(1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/libcxx/test/libcxx/diagnostics/mutex.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/mutex.nodiscard.verify.cpp
@@ -0,0 +1,21 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <mutex> functions are marked [[nodiscard]]
+
+#include <mutex>
+
+#include "test_macros.h"
+
+void test() {
+  std::mutex mutex;
+  std::lock_guard{mutex}; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::lock_guard{mutex, std::adopt_lock}; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/libcxx/test/libcxx/diagnostics/new.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/new.nodiscard.verify.cpp
@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <array> functions are marked [[nodiscard]]
+
+#include <new>
+
+#include "test_macros.h"
+
+void test() {
+  ::operator new(0);                                      // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ::operator new(0, std::nothrow);                        // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ::operator new[](0);                                    // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ::operator new[](0, std::nothrow);                      // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ::operator new(0, std::align_val_t{1});                 // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ::operator new(0, std::align_val_t{1}, std::nothrow);   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ::operator new[](0, std::align_val_t{1});               // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ::operator new[](0, std::align_val_t{1}, std::nothrow); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+#if TEST_STD_VER >= 17
+  int* ptr = nullptr;
+  std::launder(ptr); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
+}
diff --git a/...est/libcxx/diagnostics/nodiscard.pass.cpp → ...gnostics/node_handle.nodiscard.verify.cpp b/...est/libcxx/diagnostics/nodiscard.pass.cpp → ...gnostics/node_handle.nodiscard.verify.cpp
@@ -6,17 +6,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Test that _LIBCPP_NODISCARD_EXT is not defined to [[nodiscard]] when
-// _LIBCPP_DISABLE_NODISCARD_EXT is defined
+// UNSUPPORTED: c++03
 
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_NODISCARD_EXT
+// check that <__node_handle> functions are marked [[nodiscard]]
 
-#include <__config>
+#include <set>
 
-_LIBCPP_NODISCARD_EXT int foo() { return 42; }
-
-int main(int, char**) {
-  foo(); // OK.
-
-  return 0;
+void func() {
+  std::set<int> set;
+  set.extract(0).empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
 }
diff --git a/libcxx/test/libcxx/diagnostics/nodiscard_extensions.compile.pass.cpp b/libcxx/test/libcxx/diagnostics/nodiscard_extensions.compile.pass.cpp
diff --git a/...tics/pstl.nodiscard_extensions.verify.cpp → ...cxx/diagnostics/pstl.nodiscard.verify.cpp b/...tics/pstl.nodiscard_extensions.verify.cpp → ...cxx/diagnostics/pstl.nodiscard.verify.cpp
@@ -22,4 +22,5 @@ void test() {
   std::all_of(std::execution::par, std::begin(a), std::end(a), pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::any_of(std::execution::par, std::begin(a), std::end(a), pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::none_of(std::execution::par, std::begin(a), std::end(a), pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::is_partitioned(std::execution::par, std::begin(a), std::end(a), pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
 }
diff --git a/libcxx/test/libcxx/diagnostics/pstl.nodiscard_extensions.compile.pass.cpp b/libcxx/test/libcxx/diagnostics/pstl.nodiscard_extensions.compile.pass.cpp
diff --git a/libcxx/test/libcxx/diagnostics/queue.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/queue.nodiscard.verify.cpp
@@ -0,0 +1,23 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03
+
+// check that <queue> functions are marked [[nodiscard]]
+
+#include <queue>
+
+void test_queue() {
+  std::queue<int> queue;
+  queue.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
+
+void test_priority_queue() {
+  std::priority_queue<int> priority_queue;
+  priority_queue.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+}