diff --git a/libcxx/include/array b/libcxx/include/array
index ff46838e2e8e2..0b0c85458999c 100644
--- a/libcxx/include/array
+++ b/libcxx/include/array
@@ -210,28 +210,28 @@ struct array {
   }
 
   // iterators:
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator begin() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator begin() _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<_Size>(data(), data());
 #  else
     return iterator(data());
 #  endif
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator begin() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator begin() const _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<_Size>(data(), data());
 #  else
     return const_iterator(data());
 #  endif
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator end() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator end() _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<_Size>(data() + _Size, data());
 #  else
     return iterator(data() + _Size);
 #  endif
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator end() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator end() const _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<_Size>(data() + _Size, data());
 #  else
@@ -239,62 +239,81 @@ struct array {
 #  endif
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rbegin() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rbegin() _NOEXCEPT {
     return reverse_iterator(end());
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator rbegin() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator
+  rbegin() const _NOEXCEPT {
     return const_reverse_iterator(end());
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rend() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rend() _NOEXCEPT {
     return reverse_iterator(begin());
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator rend() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator rend() const _NOEXCEPT {
     return const_reverse_iterator(begin());
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cbegin() const _NOEXCEPT { return begin(); }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cend() const _NOEXCEPT { return end(); }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator crbegin() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cbegin() const _NOEXCEPT {
+    return begin();
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cend() const _NOEXCEPT {
+    return end();
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator
+  crbegin() const _NOEXCEPT {
     return rbegin();
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator crend() const _NOEXCEPT {
+    return rend();
+  }
 
   // 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; }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT { return _Size; }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT { return _Size; }
   [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT { return _Size == 0; }
 
   // element access:
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator[](size_type __n) _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator[](size_type __n) _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n < _Size, "out-of-bounds access in std::array<T, N>");
     return __elems_[__n];
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference operator[](size_type __n) const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference
+  operator[](size_type __n) const _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n < _Size, "out-of-bounds access in std::array<T, N>");
     return __elems_[__n];
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference at(size_type __n) {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference at(size_type __n) {
     if (__n >= _Size)
       std::__throw_out_of_range("array::at");
     return __elems_[__n];
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference at(size_type __n) const {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference at(size_type __n) const {
     if (__n >= _Size)
       std::__throw_out_of_range("array::at");
     return __elems_[__n];
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference front() _NOEXCEPT { return (*this)[0]; }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference front() const _NOEXCEPT { return (*this)[0]; }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference back() _NOEXCEPT { return (*this)[_Size - 1]; }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference back() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference front() _NOEXCEPT {
+    return (*this)[0];
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference front() const _NOEXCEPT {
+    return (*this)[0];
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference back() _NOEXCEPT {
+    return (*this)[_Size - 1];
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference back() const _NOEXCEPT {
     return (*this)[_Size - 1];
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 value_type* data() _NOEXCEPT { return __elems_; }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const value_type* data() const _NOEXCEPT { return __elems_; }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 value_type* data() _NOEXCEPT {
+    return __elems_;
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const value_type* data() const _NOEXCEPT {
+    return __elems_;
+  }
 };
 
 template <class _Tp>
@@ -328,8 +347,10 @@ struct array<_Tp, 0> {
   };
   _ALIGNAS_TYPE(_ArrayInStructT) _EmptyType __elems_[sizeof(_ArrayInStructT)];
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 value_type* data() _NOEXCEPT { return nullptr; }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const value_type* data() const _NOEXCEPT { return nullptr; }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 value_type* data() _NOEXCEPT { return nullptr; }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const value_type* data() const _NOEXCEPT {
+    return nullptr;
+  }
 
   // No explicit construct/copy/destroy for aggregate type
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void fill(const value_type&) {
@@ -341,28 +362,28 @@ struct array<_Tp, 0> {
   }
 
   // iterators:
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator begin() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator begin() _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<0>(data(), data());
 #  else
     return iterator(data());
 #  endif
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator begin() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator begin() const _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<0>(data(), data());
 #  else
     return const_iterator(data());
 #  endif
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator end() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 iterator end() _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<0>(data(), data());
 #  else
     return iterator(data());
 #  endif
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator end() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator end() const _NOEXCEPT {
 #  if defined(_LIBCPP_ABI_BOUNDED_ITERATORS_IN_STD_ARRAY)
     return std::__make_static_bounded_iter<0>(data(), data());
 #  else
@@ -370,68 +391,77 @@ struct array<_Tp, 0> {
 #  endif
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rbegin() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rbegin() _NOEXCEPT {
     return reverse_iterator(end());
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator rbegin() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator
+  rbegin() const _NOEXCEPT {
     return const_reverse_iterator(end());
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rend() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reverse_iterator rend() _NOEXCEPT {
     return reverse_iterator(begin());
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator rend() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator rend() const _NOEXCEPT {
     return const_reverse_iterator(begin());
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cbegin() const _NOEXCEPT { return begin(); }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cend() const _NOEXCEPT { return end(); }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator crbegin() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cbegin() const _NOEXCEPT {
+    return begin();
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_iterator cend() const _NOEXCEPT {
+    return end();
+  }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator
+  crbegin() const _NOEXCEPT {
     return rbegin();
   }
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 const_reverse_iterator crend() const _NOEXCEPT {
+    return rend();
+  }
 
   // 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; }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT { return 0; }
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT { return 0; }
   [[__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 {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator[](size_type) _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
     __libcpp_unreachable();
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference operator[](size_type) const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference
+  operator[](size_type) const _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
     __libcpp_unreachable();
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference at(size_type) {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference at(size_type) {
     std::__throw_out_of_range("array<T, 0>::at");
     __libcpp_unreachable();
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference at(size_type) const {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference at(size_type) const {
     std::__throw_out_of_range("array<T, 0>::at");
     __libcpp_unreachable();
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference front() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference front() _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(false, "cannot call array<T, 0>::front() on a zero-sized array");
     __libcpp_unreachable();
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference front() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference front() const _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(false, "cannot call array<T, 0>::front() on a zero-sized array");
     __libcpp_unreachable();
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference back() _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference back() _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(false, "cannot call array<T, 0>::back() on a zero-sized array");
     __libcpp_unreachable();
   }
 
-  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference back() const _NOEXCEPT {
+  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const_reference back() const _NOEXCEPT {
     _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(false, "cannot call array<T, 0>::back() on a zero-sized array");
     __libcpp_unreachable();
   }
@@ -501,25 +531,29 @@ struct tuple_element<_Ip, array<_Tp, _Size> > {
 };
 
 template <size_t _Ip, class _Tp, size_t _Size>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp& get(array<_Tp, _Size>& __a) _NOEXCEPT {
+[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp&
+get(array<_Tp, _Size>& __a) _NOEXCEPT {
   static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array)");
   return __a.__elems_[_Ip];
 }
 
 template <size_t _Ip, class _Tp, size_t _Size>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Tp& get(const array<_Tp, _Size>& __a) _NOEXCEPT {
+[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Tp&
+get(const array<_Tp, _Size>& __a) _NOEXCEPT {
   static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array)");
   return __a.__elems_[_Ip];
 }
 
 template <size_t _Ip, class _Tp, size_t _Size>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp&& get(array<_Tp, _Size>&& __a) _NOEXCEPT {
+[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp&&
+get(array<_Tp, _Size>&& __a) _NOEXCEPT {
   static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array &&)");
   return std::move(__a.__elems_[_Ip]);
 }
 
 template <size_t _Ip, class _Tp, size_t _Size>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Tp&& get(const array<_Tp, _Size>&& __a) _NOEXCEPT {
+[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Tp&&
+get(const array<_Tp, _Size>&& __a) _NOEXCEPT {
   static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array &&)");
   return std::move(__a.__elems_[_Ip]);
 }
@@ -539,7 +573,7 @@ __to_array_rvalue_impl(_Tp (&&__arr)[_Size], index_sequence<_Index...>) {
 }
 
 template <typename _Tp, size_t _Size>
-_LIBCPP_HIDE_FROM_ABI constexpr array<remove_cv_t<_Tp>, _Size>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr array<remove_cv_t<_Tp>, _Size>
 to_array(_Tp (&__arr)[_Size]) noexcept(is_nothrow_constructible_v<_Tp, _Tp&>) {
   static_assert(!is_array_v<_Tp>, "[array.creation]/1: to_array does not accept multidimensional arrays.");
   static_assert(is_constructible_v<_Tp, _Tp&>, "[array.creation]/1: to_array requires copy constructible elements.");
@@ -547,7 +581,7 @@ to_array(_Tp (&__arr)[_Size]) noexcept(is_nothrow_constructible_v<_Tp, _Tp&>) {
 }
 
 template <typename _Tp, size_t _Size>
-_LIBCPP_HIDE_FROM_ABI constexpr array<remove_cv_t<_Tp>, _Size>
+[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr array<remove_cv_t<_Tp>, _Size>
 to_array(_Tp (&&__arr)[_Size]) noexcept(is_nothrow_move_constructible_v<_Tp>) {
   static_assert(!is_array_v<_Tp>, "[array.creation]/4: to_array does not accept multidimensional arrays.");
   static_assert(is_move_constructible_v<_Tp>, "[array.creation]/4: to_array requires move constructible elements.");
diff --git a/libcxx/test/libcxx/diagnostics/array.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/array.nodiscard.verify.cpp
index 25a2f80b48f02..8e49807732de7 100644
--- a/libcxx/test/libcxx/diagnostics/array.nodiscard.verify.cpp
+++ b/libcxx/test/libcxx/diagnostics/array.nodiscard.verify.cpp
@@ -11,13 +11,70 @@
 // check that <array> functions are marked [[nodiscard]]
 
 #include <array>
+#include <utility>
 
-void array_test() {
-  std::array<int, 1> array;
-  array.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#include <test_macros.h>
+
+template <std::size_t N>
+void test_members() {
+  std::array<int, N> a;
+  const std::array<int, N> ca{};
+
+  a.begin();    // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.begin();   // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.end();      // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.end();     // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.rbegin();   // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.rbegin();  // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.rend();     // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.rend();    // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.cbegin();   // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.cbegin();  // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.cend();     // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.cend();    // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.crbegin();  // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.crbegin(); // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.crend();    // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.crend();   // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  a.size();     // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.max_size(); // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.empty();    // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  a[0];     // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca[0];    // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.at(0);  // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.at(0); // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  a.front();  // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.front(); // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  a.back();   // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.back();  // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  a.data();  // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  ca.data(); // expected-warning 2 {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
+
+template <typename ArrT>
+void test_get() {
+  std::array<int, 94> a{};
+
+  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::get<0>(a);
+  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::get<0>(std::move(a));
+}
+
+#if TEST_STD_VER >= 20
+void test_to_array() {
+  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::to_array("zmt");
+  // expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::to_array({94, 82, 49});
 }
+#endif
 
-void empty_array_test() {
-  std::array<int, 0> array;
-  array.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+void test() {
+  test_members<0>();
+  test_members<82>();
 }
diff --git a/libcxx/test/std/containers/sequences/array/array.creation/to_array.verify.cpp b/libcxx/test/std/containers/sequences/array/array.creation/to_array.verify.cpp
index e3efef988f0f4..ee8d8e6cfb2e5 100644
--- a/libcxx/test/std/containers/sequences/array/array.creation/to_array.verify.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.creation/to_array.verify.cpp
@@ -22,21 +22,21 @@ int main(int, char**) {
     // expected-error@array:* {{to_array does not accept multidimensional arrays}}
     // expected-error@array:* {{to_array requires copy constructible elements}}
     // expected-error@array:* 3 {{cannot initialize}}
-    std::to_array(source); // expected-note {{requested here}}
+    (void)std::to_array(source); // expected-note {{requested here}}
   }
 
   {
     MoveOnly mo[] = {MoveOnly{3}};
     // expected-error@array:* {{to_array requires copy constructible elements}}
     // expected-error-re@array:* 1-2{{{{(call to implicitly-deleted copy constructor of 'MoveOnly')|(call to deleted constructor of 'MoveOnly')}}}}
-    std::to_array(mo); // expected-note {{requested here}}
+    (void)std::to_array(mo); // expected-note {{requested here}}
   }
 
   {
     const MoveOnly cmo[] = {MoveOnly{3}};
     // expected-error@array:* {{to_array requires move constructible elements}}
     // expected-error-re@array:* 0-1{{{{(call to implicitly-deleted copy constructor of 'MoveOnly')|(call to deleted constructor of 'MoveOnly')}}}}
-    std::to_array(std::move(cmo)); // expected-note {{requested here}}
+    (void)std::to_array(std::move(cmo)); // expected-note {{requested here}}
   }
 
   return 0;