diff --git a/libcxx/include/__algorithm/equal_range.h b/libcxx/include/__algorithm/equal_range.h
--- a/libcxx/include/__algorithm/equal_range.h
+++ b/libcxx/include/__algorithm/equal_range.h
@@ -16,7 +16,10 @@
 #include <__algorithm/upper_bound.h>
 #include <__config>
 #include <__functional/identity.h>
-#include <iterator>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/pair.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__algorithm/inplace_merge.h b/libcxx/include/__algorithm/inplace_merge.h
--- a/libcxx/include/__algorithm/inplace_merge.h
+++ b/libcxx/include/__algorithm/inplace_merge.h
@@ -17,7 +17,10 @@
 #include <__algorithm/rotate.h>
 #include <__algorithm/upper_bound.h>
 #include <__config>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
+#include <__iterator/reverse_iterator.h>
 #include <__utility/swap.h>
 #include <memory>
 
diff --git a/libcxx/include/__algorithm/lower_bound.h b/libcxx/include/__algorithm/lower_bound.h
--- a/libcxx/include/__algorithm/lower_bound.h
+++ b/libcxx/include/__algorithm/lower_bound.h
@@ -13,8 +13,12 @@
 #include <__algorithm/half_positive.h>
 #include <__config>
 #include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
 #include <__type_traits/is_callable.h>
-#include <iterator>
+#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__algorithm/partition_point.h b/libcxx/include/__algorithm/partition_point.h
--- a/libcxx/include/__algorithm/partition_point.h
+++ b/libcxx/include/__algorithm/partition_point.h
@@ -11,7 +11,9 @@
 
 #include <__algorithm/half_positive.h>
 #include <__config>
-#include <iterator>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__algorithm/ranges_count.h b/libcxx/include/__algorithm/ranges_count.h
--- a/libcxx/include/__algorithm/ranges_count.h
+++ b/libcxx/include/__algorithm/ranges_count.h
@@ -15,6 +15,7 @@
 #include <__functional/ranges_operations.h>
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
 #include <__iterator/projected.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
diff --git a/libcxx/include/__algorithm/ranges_count_if.h b/libcxx/include/__algorithm/ranges_count_if.h
--- a/libcxx/include/__algorithm/ranges_count_if.h
+++ b/libcxx/include/__algorithm/ranges_count_if.h
@@ -15,6 +15,7 @@
 #include <__functional/ranges_operations.h>
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
 #include <__iterator/projected.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
diff --git a/libcxx/include/__algorithm/ranges_for_each_n.h b/libcxx/include/__algorithm/ranges_for_each_n.h
--- a/libcxx/include/__algorithm/ranges_for_each_n.h
+++ b/libcxx/include/__algorithm/ranges_for_each_n.h
@@ -15,6 +15,7 @@
 #include <__functional/invoke.h>
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
 #include <__iterator/projected.h>
 #include <__ranges/concepts.h>
 #include <__ranges/dangling.h>
diff --git a/libcxx/include/__algorithm/rotate.h b/libcxx/include/__algorithm/rotate.h
--- a/libcxx/include/__algorithm/rotate.h
+++ b/libcxx/include/__algorithm/rotate.h
@@ -18,7 +18,7 @@
 #include <__iterator/prev.h>
 #include <__utility/move.h>
 #include <__utility/swap.h>
-#include <iterator>
+#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__algorithm/sample.h b/libcxx/include/__algorithm/sample.h
--- a/libcxx/include/__algorithm/sample.h
+++ b/libcxx/include/__algorithm/sample.h
@@ -12,8 +12,10 @@
 #include <__algorithm/min.h>
 #include <__assert>
 #include <__config>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
 #include <__random/uniform_int_distribution.h>
-#include <iterator>
+#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__algorithm/sort.h b/libcxx/include/__algorithm/sort.h
--- a/libcxx/include/__algorithm/sort.h
+++ b/libcxx/include/__algorithm/sort.h
@@ -18,6 +18,7 @@
 #include <__config>
 #include <__debug>
 #include <__functional/operations.h>
+#include <__iterator/iterator_traits.h>
 #include <__utility/swap.h>
 #include <climits>
 #include <memory>
diff --git a/libcxx/include/__algorithm/stable_partition.h b/libcxx/include/__algorithm/stable_partition.h
--- a/libcxx/include/__algorithm/stable_partition.h
+++ b/libcxx/include/__algorithm/stable_partition.h
@@ -11,6 +11,8 @@
 
 #include <__algorithm/rotate.h>
 #include <__config>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
 #include <__utility/swap.h>
 #include <memory>
diff --git a/libcxx/include/__algorithm/unwrap_iter.h b/libcxx/include/__algorithm/unwrap_iter.h
--- a/libcxx/include/__algorithm/unwrap_iter.h
+++ b/libcxx/include/__algorithm/unwrap_iter.h
@@ -10,8 +10,8 @@
 #define _LIBCPP___ALGORITHM_UNWRAP_ITER_H
 
 #include <__config>
+#include <__iterator/iterator_traits.h>
 #include <__memory/pointer_traits.h>
-#include <iterator>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/__algorithm/upper_bound.h b/libcxx/include/__algorithm/upper_bound.h
--- a/libcxx/include/__algorithm/upper_bound.h
+++ b/libcxx/include/__algorithm/upper_bound.h
@@ -12,7 +12,9 @@
 #include <__algorithm/comp.h>
 #include <__algorithm/half_positive.h>
 #include <__config>
-#include <iterator>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__format/format_arg_store.h b/libcxx/include/__format/format_arg_store.h
--- a/libcxx/include/__format/format_arg_store.h
+++ b/libcxx/include/__format/format_arg_store.h
@@ -14,6 +14,8 @@
 #  pragma GCC system_header
 #endif
 
+#include <__concepts/arithmetic.h>
+#include <__concepts/same_as.h>
 #include <__config>
 #include <__format/concepts.h>
 #include <__format/format_arg.h>
diff --git a/libcxx/include/__format/formatter.h b/libcxx/include/__format/formatter.h
--- a/libcxx/include/__format/formatter.h
+++ b/libcxx/include/__format/formatter.h
@@ -15,6 +15,7 @@
 #include <__algorithm/transform.h>
 #include <__assert>
 #include <__availability>
+#include <__concepts/same_as.h>
 #include <__config>
 #include <__format/format_error.h>
 #include <__format/format_fwd.h>
diff --git a/libcxx/include/__hash_table b/libcxx/include/__hash_table
--- a/libcxx/include/__hash_table
+++ b/libcxx/include/__hash_table
@@ -17,10 +17,10 @@
 #include <__config>
 #include <__debug>
 #include <__functional/hash.h>
+#include <__iterator/iterator_traits.h>
 #include <__utility/swap.h>
 #include <cmath>
 #include <initializer_list>
-#include <iterator>
 #include <memory>
 #include <type_traits>
 
diff --git a/libcxx/include/__memory/raw_storage_iterator.h b/libcxx/include/__memory/raw_storage_iterator.h
--- a/libcxx/include/__memory/raw_storage_iterator.h
+++ b/libcxx/include/__memory/raw_storage_iterator.h
@@ -11,10 +11,11 @@
 #define _LIBCPP___MEMORY_RAW_STORAGE_ITERATOR_H
 
 #include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
 #include <__utility/move.h>
 #include <cstddef>
-#include <iterator>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/__tree b/libcxx/include/__tree
--- a/libcxx/include/__tree
+++ b/libcxx/include/__tree
@@ -11,10 +11,14 @@
 #define _LIBCPP___TREE
 
 #include <__algorithm/min.h>
+#include <__assert>
 #include <__config>
+#include <__debug>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
 #include <__utility/forward.h>
 #include <__utility/swap.h>
-#include <iterator>
 #include <limits>
 #include <memory>
 #include <stdexcept>
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -1068,7 +1068,7 @@
 #include <cstddef>
 #include <cstring>
 #include <initializer_list>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <memory>
 #include <type_traits>
 #include <version>
diff --git a/libcxx/include/any b/libcxx/include/any
--- a/libcxx/include/any
+++ b/libcxx/include/any
@@ -88,6 +88,7 @@
 #include <__utility/move.h>
 #include <__utility/unreachable.h>
 #include <cstdlib>
+#include <initializer_list>
 #include <memory>
 #include <type_traits>
 #include <typeinfo>
diff --git a/libcxx/include/array b/libcxx/include/array
--- a/libcxx/include/array
+++ b/libcxx/include/array
@@ -114,11 +114,13 @@
 #include <__algorithm/swap_ranges.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
+#include <__iterator/reverse_iterator.h>
 #include <__tuple>
 #include <__utility/integer_sequence.h>
 #include <__utility/move.h>
 #include <__utility/unreachable.h>
-#include <iterator>
+#include <compare>
+#include <iterator> // TODO: Remove this include
 #include <stdexcept>
 #include <type_traits>
 #include <version>
diff --git a/libcxx/include/deque b/libcxx/include/deque
--- a/libcxx/include/deque
+++ b/libcxx/include/deque
@@ -173,13 +173,16 @@
 #include <__config>
 #include <__format/enable_insertable.h>
 #include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__iterator/prev.h>
+#include <__iterator/reverse_iterator.h>
 #include <__split_buffer>
 #include <__utility/forward.h>
 #include <__utility/move.h>
 #include <__utility/swap.h>
 #include <compare>
 #include <initializer_list>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <limits>
 #include <stdexcept>
 #include <type_traits>
diff --git a/libcxx/include/ext/hash_map b/libcxx/include/ext/hash_map
--- a/libcxx/include/ext/hash_map
+++ b/libcxx/include/ext/hash_map
@@ -207,6 +207,7 @@
 #include <algorithm>
 #include <ext/__hash>
 #include <functional>
+#include <iterator> // TODO: Remove this include
 #include <stdexcept>
 #include <type_traits>
 
diff --git a/libcxx/include/ext/hash_set b/libcxx/include/ext/hash_set
--- a/libcxx/include/ext/hash_set
+++ b/libcxx/include/ext/hash_set
@@ -198,6 +198,7 @@
 #include <algorithm>
 #include <ext/__hash>
 #include <functional>
+#include <iterator> // TODO: Remove this include
 
 #if defined(__DEPRECATED) && __DEPRECATED
 #if defined(_LIBCPP_WARNING)
diff --git a/libcxx/include/format b/libcxx/include/format
--- a/libcxx/include/format
+++ b/libcxx/include/format
@@ -146,6 +146,7 @@
 #include <__format/formatter_pointer.h>
 #include <__format/formatter_string.h>
 #include <__format/parser_std_format_spec.h>
+#include <__iterator/incrementable_traits.h>
 #include <__variant/monostate.h>
 #include <array>
 #include <concepts>
diff --git a/libcxx/include/forward_list b/libcxx/include/forward_list
--- a/libcxx/include/forward_list
+++ b/libcxx/include/forward_list
@@ -184,9 +184,13 @@
 #include <__algorithm/min.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/move_iterator.h>
+#include <__iterator/next.h>
 #include <__utility/forward.h>
 #include <initializer_list>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <limits>
 #include <memory>
 #include <type_traits>
diff --git a/libcxx/include/istream b/libcxx/include/istream
--- a/libcxx/include/istream
+++ b/libcxx/include/istream
@@ -160,6 +160,7 @@
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
+#include <__iterator/istreambuf_iterator.h>
 #include <__utility/forward.h>
 #include <ostream>
 #include <version>
diff --git a/libcxx/include/list b/libcxx/include/list
--- a/libcxx/include/list
+++ b/libcxx/include/list
@@ -188,11 +188,17 @@
 #include <__config>
 #include <__debug>
 #include <__format/enable_insertable.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/move_iterator.h>
+#include <__iterator/next.h>
+#include <__iterator/prev.h>
+#include <__iterator/reverse_iterator.h>
 #include <__utility/forward.h>
 #include <__utility/move.h>
 #include <__utility/swap.h>
 #include <initializer_list>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <limits>
 #include <memory>
 #include <type_traits>
diff --git a/libcxx/include/locale b/libcxx/include/locale
--- a/libcxx/include/locale
+++ b/libcxx/include/locale
@@ -196,6 +196,10 @@
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
 #include <__debug>
+#include <__iterator/access.h>
+#include <__iterator/back_insert_iterator.h>
+#include <__iterator/istreambuf_iterator.h>
+#include <__iterator/ostreambuf_iterator.h>
 #include <__locale>
 #ifndef __APPLE__
 # include <cstdarg>
@@ -204,7 +208,7 @@
 #include <cstdlib>
 #include <ctime>
 #include <ios>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <limits>
 #include <memory>
 #include <streambuf>
diff --git a/libcxx/include/map b/libcxx/include/map
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -535,14 +535,16 @@
 #include <__functional/binary_function.h>
 #include <__functional/is_transparent.h>
 #include <__functional/operations.h>
+#include <__iterator/erase_if_container.h>
 #include <__iterator/iterator_traits.h>
+#include <__iterator/reverse_iterator.h>
 #include <__node_handle>
 #include <__tree>
 #include <__utility/forward.h>
 #include <__utility/swap.h>
 #include <compare>
 #include <initializer_list>
-#include <iterator> // __libcpp_erase_if_container
+#include <iterator> // TODO: Remove this include
 #include <memory>
 #include <type_traits>
 #include <version>
diff --git a/libcxx/include/memory b/libcxx/include/memory
--- a/libcxx/include/memory
+++ b/libcxx/include/memory
@@ -864,7 +864,7 @@
 #include <cstdint>
 #include <cstring>
 #include <iosfwd>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <new>
 #include <stdexcept>
 #include <tuple>
diff --git a/libcxx/include/numeric b/libcxx/include/numeric
--- a/libcxx/include/numeric
+++ b/libcxx/include/numeric
@@ -147,7 +147,7 @@
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
 #include <cmath> // for isnormal
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <version>
 
 #include <__numeric/accumulate.h>
diff --git a/libcxx/include/ostream b/libcxx/include/ostream
--- a/libcxx/include/ostream
+++ b/libcxx/include/ostream
@@ -138,7 +138,7 @@
 #include <__config>
 #include <bitset>
 #include <ios>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <locale>
 #include <streambuf>
 #include <version>
diff --git a/libcxx/include/regex b/libcxx/include/regex
--- a/libcxx/include/regex
+++ b/libcxx/include/regex
@@ -766,6 +766,8 @@
 #include <__algorithm/search.h>
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
+#include <__iterator/access.h>
+#include <__iterator/back_insert_iterator.h>
 #include <__iterator/wrap_iter.h>
 #include <__locale>
 #include <__utility/move.h>
@@ -773,7 +775,7 @@
 #include <compare>
 #include <deque>
 #include <initializer_list>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <memory>
 #include <stdexcept>
 #include <string>
diff --git a/libcxx/include/set b/libcxx/include/set
--- a/libcxx/include/set
+++ b/libcxx/include/set
@@ -477,13 +477,15 @@
 #include <__config>
 #include <__functional/is_transparent.h>
 #include <__functional/operations.h>
+#include <__iterator/erase_if_container.h>
 #include <__iterator/iterator_traits.h>
+#include <__iterator/reverse_iterator.h>
 #include <__node_handle>
 #include <__tree>
 #include <__utility/forward.h>
 #include <compare>
 #include <initializer_list>
-#include <iterator> // __libcpp_erase_if_container
+#include <iterator> // TODO: Remove this include
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/span b/libcxx/include/span
--- a/libcxx/include/span
+++ b/libcxx/include/span
@@ -132,7 +132,9 @@
 #include <__debug>
 #include <__fwd/span.h>
 #include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
 #include <__iterator/wrap_iter.h>
+#include <__memory/pointer_traits.h>
 #include <__ranges/concepts.h>
 #include <__ranges/data.h>
 #include <__ranges/enable_borrowed_range.h>
@@ -141,7 +143,7 @@
 #include <__utility/forward.h>
 #include <array>        // for array
 #include <cstddef>      // for byte
-#include <iterator>     // for iterators
+#include <iterator> // TODO: Remove this include
 #include <limits>
 #include <type_traits>  // for remove_cv, etc
 #include <version>
diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -527,6 +527,9 @@
 #include <__functional/hash.h>
 #include <__functional/unary_function.h>
 #include <__ios/fpos.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/reverse_iterator.h>
 #include <__iterator/wrap_iter.h>
 #include <__memory/allocate_at_least.h>
 #include <__string/char_traits.h>
@@ -542,7 +545,7 @@
 #include <cstring>
 #include <initializer_list>
 #include <iosfwd>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <limits>
 #include <memory>
 #include <stdexcept>
diff --git a/libcxx/include/string_view b/libcxx/include/string_view
--- a/libcxx/include/string_view
+++ b/libcxx/include/string_view
@@ -202,6 +202,10 @@
 #include <__functional/hash.h>
 #include <__functional/unary_function.h>
 #include <__fwd/string_view.h>
+#include <__iterator/concepts.h>
+#include <__iterator/readable_traits.h>
+#include <__iterator/reverse_iterator.h>
+#include <__memory/pointer_traits.h>
 #include <__ranges/concepts.h>
 #include <__ranges/data.h>
 #include <__ranges/enable_borrowed_range.h>
@@ -210,7 +214,7 @@
 #include <__string/char_traits.h>
 #include <compare>
 #include <iosfwd>
-#include <iterator>
+#include <iterator> // TODO: Remove this include
 #include <limits>
 #include <stdexcept>
 #include <type_traits>
diff --git a/libcxx/include/unordered_map b/libcxx/include/unordered_map
--- a/libcxx/include/unordered_map
+++ b/libcxx/include/unordered_map
@@ -521,12 +521,14 @@
 #include <__functional/is_transparent.h>
 #include <__functional/operations.h>
 #include <__hash_table>
+#include <__iterator/distance.h>
+#include <__iterator/erase_if_container.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
 #include <__node_handle>
 #include <__utility/forward.h>
 #include <compare>
-#include <iterator> // __libcpp_erase_if_container
+#include <iterator> // TODO: Remove this include
 #include <stdexcept>
 #include <tuple>
 #include <version>
diff --git a/libcxx/include/unordered_set b/libcxx/include/unordered_set
--- a/libcxx/include/unordered_set
+++ b/libcxx/include/unordered_set
@@ -466,11 +466,14 @@
 #include <__functional/is_transparent.h>
 #include <__functional/operations.h>
 #include <__hash_table>
+#include <__iterator/distance.h>
+#include <__iterator/erase_if_container.h>
+#include <__iterator/iterator_traits.h>
 #include <__memory/addressof.h>
 #include <__node_handle>
 #include <__utility/forward.h>
 #include <compare>
-#include <iterator> // __libcpp_erase_if_container
+#include <iterator> // TODO: Remove this include
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/vector b/libcxx/include/vector
--- a/libcxx/include/vector
+++ b/libcxx/include/vector
@@ -286,7 +286,9 @@
 #include <__format/enable_insertable.h>
 #include <__functional/hash.h>
 #include <__functional/unary_function.h>
+#include <__iterator/advance.h>
 #include <__iterator/iterator_traits.h>
+#include <__iterator/reverse_iterator.h>
 #include <__iterator/wrap_iter.h>
 #include <__memory/allocate_at_least.h>
 #include <__split_buffer>
diff --git a/libcxx/src/include/to_chars_floating_point.h b/libcxx/src/include/to_chars_floating_point.h
--- a/libcxx/src/include/to_chars_floating_point.h
+++ b/libcxx/src/include/to_chars_floating_point.h
@@ -23,6 +23,7 @@
 #include <__algorithm/min.h>
 #include <__assert>
 #include <__config>
+#include <__functional/operations.h>
 #include <__iterator/access.h>
 #include <__iterator/size.h>
 #include <bit>
diff --git a/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy.pass.cpp b/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy.pass.cpp
--- a/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy.pass.cpp
+++ b/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy.pass.cpp
@@ -18,6 +18,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <iterator>
 #include <type_traits>
 
 struct S {
diff --git a/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_sentinel_for.compile.pass.cpp b/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_sentinel_for.compile.pass.cpp
--- a/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_sentinel_for.compile.pass.cpp
+++ b/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_sentinel_for.compile.pass.cpp
@@ -12,6 +12,7 @@
 // template<class S, class I>
 // concept __nothrow_sentinel_for;
 
+#include <iterator>
 #include <memory>
 
 static_assert(std::ranges::__nothrow_sentinel_for<int*, int*>);
diff --git a/libcxx/test/libcxx/fuzzing/fuzz.h b/libcxx/test/libcxx/fuzzing/fuzz.h
--- a/libcxx/test/libcxx/fuzzing/fuzz.h
+++ b/libcxx/test/libcxx/fuzzing/fuzz.h
@@ -13,6 +13,7 @@
 #include <cstddef>
 #include <cstdint>
 #include <cstring> // std::strlen
+#include <iterator>
 #include <type_traits>
 #include <utility> // std::swap
 
diff --git a/libcxx/test/libcxx/numerics/numeric.ops/midpoint.integer.pass.cpp b/libcxx/test/libcxx/numerics/numeric.ops/midpoint.integer.pass.cpp
--- a/libcxx/test/libcxx/numerics/numeric.ops/midpoint.integer.pass.cpp
+++ b/libcxx/test/libcxx/numerics/numeric.ops/midpoint.integer.pass.cpp
@@ -15,6 +15,7 @@
 
 #include <numeric>
 #include <cassert>
+#include <cstdint>
 #include "test_macros.h"
 
 //  Users are not supposed to provide template argument lists for
diff --git a/libcxx/test/std/algorithms/robust_against_adl.compile.pass.cpp b/libcxx/test/std/algorithms/robust_against_adl.compile.pass.cpp
--- a/libcxx/test/std/algorithms/robust_against_adl.compile.pass.cpp
+++ b/libcxx/test/std/algorithms/robust_against_adl.compile.pass.cpp
@@ -11,6 +11,7 @@
 #include <algorithm>
 #include <cstddef>
 #include <functional>
+#include <iterator>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/containers/associative/map/map.cons/deduct_const.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/deduct_const.pass.cpp
--- a/libcxx/test/std/containers/associative/map/map.cons/deduct_const.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/deduct_const.pass.cpp
@@ -29,6 +29,7 @@
 #include <cassert>
 #include <climits> // INT_MAX
 #include <functional>
+#include <iterator>
 #include <map>
 #include <type_traits>
 
diff --git a/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp
--- a/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/map.cons/move_alloc.pass.cpp
@@ -16,6 +16,7 @@
 
 #include <map>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "MoveOnly.h"
diff --git a/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct_const.pass.cpp b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct_const.pass.cpp
--- a/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct_const.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/multimap.cons/deduct_const.pass.cpp
@@ -29,6 +29,7 @@
 #include <cassert>
 #include <climits> // INT_MAX
 #include <functional>
+#include <iterator>
 #include <map>
 #include <type_traits>
 
diff --git a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp
--- a/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/multiset.cons/move_alloc.pass.cpp
@@ -16,6 +16,7 @@
 
 #include <set>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "MoveOnly.h"
diff --git a/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp b/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp
--- a/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/insert_iter_rv.pass.cpp
@@ -16,6 +16,7 @@
 
 #include <set>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "MoveOnly.h"
diff --git a/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp b/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp
--- a/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/set.cons/move_alloc.pass.cpp
@@ -16,6 +16,7 @@
 
 #include <set>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "MoveOnly.h"
diff --git a/libcxx/test/std/containers/map_allocator_requirement_test_templates.h b/libcxx/test/std/containers/map_allocator_requirement_test_templates.h
--- a/libcxx/test/std/containers/map_allocator_requirement_test_templates.h
+++ b/libcxx/test/std/containers/map_allocator_requirement_test_templates.h
@@ -21,6 +21,7 @@
 // UNSUPPORTED: c++03
 
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "count_new.h"
diff --git a/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp b/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp
--- a/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.data/data.pass.cpp
@@ -13,6 +13,7 @@
 #include <array>
 #include <cassert>
 #include <cstddef>       // for std::max_align_t
+#include <cstdint>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp b/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp
--- a/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/array.data/data_const.pass.cpp
@@ -13,6 +13,7 @@
 #include <array>
 #include <cassert>
 #include <cstddef>       // for std::max_align_t
+#include <cstdint>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/clear.pass.cpp
@@ -12,6 +12,7 @@
 
 #include <forward_list>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "../../../NotConstructible.h"
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_many.pass.cpp
@@ -12,6 +12,7 @@
 
 #include <forward_list>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/erase_after_one.pass.cpp
@@ -12,6 +12,7 @@
 
 #include <forward_list>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size.pass.cpp
@@ -12,6 +12,7 @@
 
 #include <forward_list>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "DefaultOnly.h"
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.modifiers/resize_size_value.pass.cpp
@@ -12,6 +12,7 @@
 
 #include <forward_list>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "DefaultOnly.h"
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/member_swap.pass.cpp
@@ -13,6 +13,7 @@
 
 #include <forward_list>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "test_allocator.h"
diff --git a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/forwardlist.spec/non_member_swap.pass.cpp
@@ -14,6 +14,7 @@
 
 #include <forward_list>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "test_allocator.h"
diff --git a/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp
--- a/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/erase_iter.pass.cpp
@@ -13,6 +13,7 @@
 
 #include <vector>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp
--- a/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/erase_iter_iter.pass.cpp
@@ -13,6 +13,7 @@
 
 #include <vector>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp
--- a/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/vector_bool.pass.cpp
@@ -19,6 +19,7 @@
 
 #include <vector>
 #include <cassert>
+#include <iterator>
 #include <type_traits>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/containers/set_allocator_requirement_test_templates.h b/libcxx/test/std/containers/set_allocator_requirement_test_templates.h
--- a/libcxx/test/std/containers/set_allocator_requirement_test_templates.h
+++ b/libcxx/test/std/containers/set_allocator_requirement_test_templates.h
@@ -20,6 +20,7 @@
 
 
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "count_new.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp b/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/bucket.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/bucket_count.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp b/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/bucket_size.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/count.pass.cpp b/libcxx/test/std/containers/unord/unord.map/count.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/count.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp b/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/eq.pass.cpp
@@ -21,6 +21,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/equal_range_const.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/equal_range_non_const.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/find_const.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/find_non_const.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/load_factor.pass.cpp
@@ -19,6 +19,7 @@
 #include <cassert>
 #include <cmath>
 #include <cfloat>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp b/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/swap_member.pass.cpp
@@ -18,6 +18,7 @@
 #include <string>
 #include <cassert>
 #include <cstddef>
+#include <iterator>
 
 #include "../../test_compare.h"
 #include "../../test_hash.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct.pass.cpp
@@ -58,6 +58,7 @@
 #include <algorithm> // is_permutation
 #include <cassert>
 #include <climits> // INT_MAX
+#include <iterator>
 #include <type_traits>
 #include <unordered_map>
 
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct_const.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.cnstr/deduct_const.pass.cpp
@@ -58,6 +58,7 @@
 #include <algorithm> // std::is_permutation
 #include <cassert>
 #include <climits> // INT_MAX
+#include <iterator>
 #include <type_traits>
 #include <unordered_map>
 
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/erase_range.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/extract_key.pass.cpp
@@ -14,7 +14,9 @@
 
 // node_type extract(key_type const&);
 
+#include <iterator>
 #include <unordered_map>
+
 #include "test_macros.h"
 #include "min_allocator.h"
 #include "Counter.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/insert_or_assign.pass.cpp
@@ -23,6 +23,7 @@
 
 #include <unordered_map>
 #include <cassert>
+#include <iterator>
 #include <tuple>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/unord.map.modifiers/try.emplace.pass.cpp
@@ -23,6 +23,7 @@
 
 #include <unordered_map>
 #include <cassert>
+#include <iterator>
 #include <tuple>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/bucket.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/bucket_count.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/bucket_size.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/count.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/eq.pass.cpp
@@ -21,6 +21,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/equal_range_const.pass.cpp
@@ -18,6 +18,7 @@
 #include <string>
 #include <set>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/equal_range_non_const.pass.cpp
@@ -18,6 +18,7 @@
 #include <string>
 #include <set>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/find_const.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/find_non_const.pass.cpp
@@ -17,6 +17,7 @@
 #include <unordered_map>
 #include <string>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/load_factor.pass.cpp
@@ -19,6 +19,7 @@
 #include <cassert>
 #include <cfloat>
 #include <cmath>
+#include <iterator>
 
 #include "test_macros.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/swap_member.pass.cpp
@@ -19,6 +19,7 @@
 #include <set>
 #include <cassert>
 #include <cstddef>
+#include <iterator>
 
 #include "test_macros.h"
 #include "../../test_compare.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/deduct_const.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/deduct_const.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/deduct_const.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.cnstr/deduct_const.pass.cpp
@@ -59,6 +59,7 @@
 #include <cassert>
 #include <climits> // INT_MAX
 #include <functional>
+#include <iterator>
 #include <type_traits>
 #include <unordered_map>
 
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.modifiers/emplace_hint.pass.cpp
@@ -20,6 +20,7 @@
 
 #include <unordered_map>
 #include <cassert>
+#include <iterator>
 
 #include "../../../Emplaceable.h"
 #include "min_allocator.h"
diff --git a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/unord.multimap.swap/swap_non_member.pass.cpp
@@ -19,6 +19,7 @@
 #include <set>
 #include <cassert>
 #include <cstddef>
+#include <iterator>
 
 #include "test_macros.h"
 #include "../../../check_consecutive.h"
diff --git a/libcxx/test/std/containers/views/views.span/span.cons/assign.pass.cpp b/libcxx/test/std/containers/views/views.span/span.cons/assign.pass.cpp
--- a/libcxx/test/std/containers/views/views.span/span.cons/assign.pass.cpp
+++ b/libcxx/test/std/containers/views/views.span/span.cons/assign.pass.cpp
@@ -13,6 +13,7 @@
 
 #include <span>
 #include <cassert>
+#include <iterator>
 #include <string>
 #include <utility>
 
diff --git a/libcxx/test/std/containers/views/views.span/span.cons/deduct.pass.cpp b/libcxx/test/std/containers/views/views.span/span.cons/deduct.pass.cpp
--- a/libcxx/test/std/containers/views/views.span/span.cons/deduct.pass.cpp
+++ b/libcxx/test/std/containers/views/views.span/span.cons/deduct.pass.cpp
@@ -28,6 +28,7 @@
 #include <span>
 #include <array>
 #include <cassert>
+#include <iterator>
 #include <memory>
 #include <string>
 
diff --git a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp
--- a/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.regiter/re.regiter.incr/post.pass.cpp
@@ -14,6 +14,7 @@
 
 #include <regex>
 #include <cassert>
+#include <iterator>
 #include "test_macros.h"
 
 int main(int, char**)
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/array.pass.cpp
@@ -19,6 +19,8 @@
 
 #include <regex>
 #include <cassert>
+#include <iterator>
+
 #include "test_macros.h"
 
 int main(int, char**)
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/init.pass.cpp
@@ -20,6 +20,8 @@
 
 #include <regex>
 #include <cassert>
+#include <iterator>
+
 #include "test_macros.h"
 
 int main(int, char**)
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/int.pass.cpp
@@ -17,6 +17,8 @@
 
 #include <regex>
 #include <cassert>
+#include <iterator>
+
 #include "test_macros.h"
 
 int main(int, char**)
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.cnstr/vector.pass.cpp
@@ -18,6 +18,8 @@
 
 #include <regex>
 #include <cassert>
+#include <iterator>
+
 #include "test_macros.h"
 
 int main(int, char**)
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.deref/deref.pass.cpp
@@ -14,6 +14,8 @@
 
 #include <regex>
 #include <cassert>
+#include <iterator>
+
 #include "test_macros.h"
 
 int main(int, char**)
diff --git a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp
--- a/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp
+++ b/libcxx/test/std/re/re.iter/re.tokiter/re.tokiter.incr/post.pass.cpp
@@ -14,6 +14,8 @@
 
 #include <regex>
 #include <cassert>
+#include <iterator>
+
 #include "test_macros.h"
 
 int main(int, char**)
diff --git a/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp b/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp
--- a/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.access/data.pass.cpp
@@ -14,6 +14,7 @@
 
 #include <string_view>
 #include <cassert>
+#include <iterator>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp b/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp
--- a/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp
+++ b/libcxx/test/std/strings/string.view/string.view.capacity/capacity.pass.cpp
@@ -18,6 +18,7 @@
 
 #include <string_view>
 #include <cassert>
+#include <iterator>
 #include <limits>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp b/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp
--- a/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.msvc/test.cpp
@@ -11,6 +11,7 @@
 #include <cmath>
 #include <fstream>
 #include <functional>
+#include <iterator>
 #include <limits>
 #include <locale>
 #include <optional>
diff --git a/libcxx/test/std/utilities/format/format.functions/format_tests.h b/libcxx/test/std/utilities/format/format.functions/format_tests.h
--- a/libcxx/test/std/utilities/format/format.functions/format_tests.h
+++ b/libcxx/test/std/utilities/format/format.functions/format_tests.h
@@ -11,9 +11,11 @@
 #include <format>
 
 #include <algorithm>
+#include <cassert>
 #include <charconv>
 #include <cmath>
 #include <cstdint>
+#include <iterator>
 
 #include "make_string.h"
 #include "string_literal.h"
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocate_at_least.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocate_at_least.pass.cpp
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocate_at_least.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocate_at_least.pass.cpp
@@ -15,6 +15,7 @@
 //   allocate_at_least(Allocator& a, size_t n);
 
 #include <cassert>
+#include <concepts>
 #include <memory>
 
 // check that std::allocation_result exists and isn't restricted to pointers
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate_at_least.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate_at_least.pass.cpp
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate_at_least.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate_at_least.pass.cpp
@@ -13,6 +13,7 @@
 // allocation_result<T*> allocate_at_least(size_t n)
 
 #include <cassert>
+#include <concepts>
 #include <memory>
 
 #include "count_new.h"
diff --git a/libcxx/test/std/utilities/memory/storage.iterator/types.compile.pass.cpp b/libcxx/test/std/utilities/memory/storage.iterator/types.compile.pass.cpp
--- a/libcxx/test/std/utilities/memory/storage.iterator/types.compile.pass.cpp
+++ b/libcxx/test/std/utilities/memory/storage.iterator/types.compile.pass.cpp
@@ -12,6 +12,7 @@
 // raw_storage_iterator associated types
 
 #include <cstddef>
+#include <iterator>
 #include <memory>
 #include <type_traits>
 
diff --git a/libcxx/test/support/archetypes.h b/libcxx/test/support/archetypes.h
--- a/libcxx/test/support/archetypes.h
+++ b/libcxx/test/support/archetypes.h
@@ -11,6 +11,7 @@
 
 #include <type_traits>
 #include <cassert>
+#include <initializer_list>
 
 #include "test_macros.h"
 #include "test_workarounds.h"
diff --git a/libcxx/test/support/deduction_guides_sfinae_checks.h b/libcxx/test/support/deduction_guides_sfinae_checks.h
--- a/libcxx/test/support/deduction_guides_sfinae_checks.h
+++ b/libcxx/test/support/deduction_guides_sfinae_checks.h
@@ -11,6 +11,7 @@
 
 #include <functional>
 #include <initializer_list>
+#include <iterator>
 #include <memory>
 #include <type_traits>
 #include <utility>
diff --git a/libcxx/test/support/min_allocator.h b/libcxx/test/support/min_allocator.h
--- a/libcxx/test/support/min_allocator.h
+++ b/libcxx/test/support/min_allocator.h
@@ -14,6 +14,7 @@
 #include <cstddef>
 #include <cassert>
 #include <climits>
+#include <iterator>
 #include <memory>
 
 #include "test_macros.h"