diff --git a/libcxx/include/__iterator/advance.h b/libcxx/include/__iterator/advance.h
--- a/libcxx/include/__iterator/advance.h
+++ b/libcxx/include/__iterator/advance.h
@@ -15,6 +15,7 @@
 #include <__function_like.h>
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
 #include <concepts>
 #include <limits>
 #include <type_traits>
diff --git a/libcxx/include/__iterator/next.h b/libcxx/include/__iterator/next.h
--- a/libcxx/include/__iterator/next.h
+++ b/libcxx/include/__iterator/next.h
@@ -11,10 +11,13 @@
 #define _LIBCPP___ITERATOR_NEXT_H
 
 #include <__config>
+#include <__debug>
 #include <__function_like.h>
 #include <__iterator/advance.h>
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
diff --git a/libcxx/include/__iterator/prev.h b/libcxx/include/__iterator/prev.h
--- a/libcxx/include/__iterator/prev.h
+++ b/libcxx/include/__iterator/prev.h
@@ -11,10 +11,13 @@
 #define _LIBCPP___ITERATOR_PREV_H
 
 #include <__config>
+#include <__debug>
 #include <__function_like.h>
 #include <__iterator/advance.h>
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
diff --git a/libcxx/include/__memory/allocation_guard.h b/libcxx/include/__memory/allocation_guard.h
--- a/libcxx/include/__memory/allocation_guard.h
+++ b/libcxx/include/__memory/allocation_guard.h
@@ -13,6 +13,7 @@
 #include <__config>
 #include <__memory/allocator_traits.h>
 #include <cstddef>
+#include <utility>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
diff --git a/libcxx/include/__memory/allocator_traits.h b/libcxx/include/__memory/allocator_traits.h
--- a/libcxx/include/__memory/allocator_traits.h
+++ b/libcxx/include/__memory/allocator_traits.h
@@ -361,6 +361,8 @@
 template <class _Tp>
 struct __is_default_allocator : false_type { };
 
+template <class> class allocator;
+
 template <class _Tp>
 struct __is_default_allocator<allocator<_Tp> > : true_type { };
 
diff --git a/libcxx/include/__memory/auto_ptr.h b/libcxx/include/__memory/auto_ptr.h
--- a/libcxx/include/__memory/auto_ptr.h
+++ b/libcxx/include/__memory/auto_ptr.h
@@ -11,6 +11,7 @@
 #define _LIBCPP___MEMORY_AUTO_PTR_H
 
 #include <__config>
+#include <__nullptr>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
diff --git a/libcxx/include/__memory/pointer_safety.h b/libcxx/include/__memory/pointer_safety.h
--- a/libcxx/include/__memory/pointer_safety.h
+++ b/libcxx/include/__memory/pointer_safety.h
@@ -11,6 +11,7 @@
 #define _LIBCPP___MEMORY_POINTER_SAFETY_H
 
 #include <__config>
+#include <cstddef>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
diff --git a/libcxx/include/__memory/pointer_traits.h b/libcxx/include/__memory/pointer_traits.h
--- a/libcxx/include/__memory/pointer_traits.h
+++ b/libcxx/include/__memory/pointer_traits.h
@@ -11,6 +11,7 @@
 #define _LIBCPP___MEMORY_POINTER_TRAITS_H
 
 #include <__config>
+#include <__memory/addressof.h>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/__ranges/access.h b/libcxx/include/__ranges/access.h
--- a/libcxx/include/__ranges/access.h
+++ b/libcxx/include/__ranges/access.h
@@ -11,7 +11,9 @@
 
 #include <__config>
 #include <__iterator/concepts.h>
+#include <__iterator/readable_traits.h>
 #include <__ranges/enable_borrowed_range.h>
+#include <concepts>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/__ranges/concepts.h b/libcxx/include/__ranges/concepts.h
--- a/libcxx/include/__ranges/concepts.h
+++ b/libcxx/include/__ranges/concepts.h
@@ -11,9 +11,15 @@
 
 #include <__config>
 #include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/readable_traits.h>
 #include <__ranges/access.h>
+#include <__ranges/enable_borrowed_range.h>
 #include <__ranges/enable_view.h>
 #include <__ranges/size.h>
+#include <concepts>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/__ranges/data.h b/libcxx/include/__ranges/data.h
--- a/libcxx/include/__ranges/data.h
+++ b/libcxx/include/__ranges/data.h
@@ -12,6 +12,7 @@
 #include <__config>
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
+#include <__memory/pointer_traits.h>
 #include <__ranges/access.h>
 #include <concepts>
 #include <type_traits>
diff --git a/libcxx/include/__ranges/empty.h b/libcxx/include/__ranges/empty.h
--- a/libcxx/include/__ranges/empty.h
+++ b/libcxx/include/__ranges/empty.h
@@ -11,6 +11,7 @@
 
 #include <__config>
 #include <__iterator/concepts.h>
+#include <__ranges/access.h>
 #include <__ranges/size.h>
 #include <type_traits>
 
diff --git a/libcxx/include/__ranges/size.h b/libcxx/include/__ranges/size.h
--- a/libcxx/include/__ranges/size.h
+++ b/libcxx/include/__ranges/size.h
@@ -13,6 +13,7 @@
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__ranges/access.h>
+#include <concepts>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/__ranges/view_interface.h b/libcxx/include/__ranges/view_interface.h
--- a/libcxx/include/__ranges/view_interface.h
+++ b/libcxx/include/__ranges/view_interface.h
@@ -13,9 +13,12 @@
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/prev.h>
+#include <__memory/pointer_traits.h>
 #include <__ranges/access.h>
+#include <__ranges/concepts.h>
 #include <__ranges/empty.h>
 #include <__ranges/enable_view.h>
+#include <concepts>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
@@ -21,11 +21,13 @@
 // template <class Rep, class Period>
 //   shared_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
 
-#include <shared_mutex>
 #include <thread>
-#include <vector>
-#include <cstdlib>
+
+#include <atomic>
 #include <cassert>
+#include <cstdlib>
+#include <shared_mutex>
+#include <vector>
 
 #include "make_test_thread.h"
 #include "test_macros.h"
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
@@ -21,11 +21,13 @@
 // template <class Clock, class Duration>
 //   shared_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
 
-#include <shared_mutex>
 #include <thread>
-#include <vector>
-#include <cstdlib>
+
+#include <atomic>
 #include <cassert>
+#include <cstdlib>
+#include <shared_mutex>
+#include <vector>
 
 #include "make_test_thread.h"
 #include "test_macros.h"
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
@@ -20,10 +20,12 @@
 
 // void lock();
 
-#include <shared_mutex>
 #include <thread>
+
+#include <atomic>
 #include <cstdlib>
 #include <cassert>
+#include <shared_mutex>
 
 #include "make_test_thread.h"
 #include "test_macros.h"
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
@@ -20,11 +20,13 @@
 
 // void lock_shared();
 
-#include <shared_mutex>
 #include <thread>
-#include <vector>
-#include <cstdlib>
+
+#include <atomic>
 #include <cassert>
+#include <cstdlib>
+#include <shared_mutex>
+#include <vector>
 
 #include "make_test_thread.h"
 #include "test_macros.h"
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
@@ -23,11 +23,13 @@
 // template <class Clock, class Duration>
 //     bool try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time);
 
-#include <shared_mutex>
 #include <thread>
-#include <vector>
-#include <cstdlib>
+
+#include <atomic>
 #include <cassert>
+#include <cstdlib>
+#include <shared_mutex>
+#include <vector>
 
 #include "make_test_thread.h"
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp
@@ -13,7 +13,9 @@
 // constexpr void advance_to(const_iterator it);
 
 #include <format>
+
 #include <cassert>
+#include <string_view>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp
@@ -13,7 +13,9 @@
 // constexpr begin() const noexcept;
 
 #include <format>
+
 #include <cassert>
+#include <string_view>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
@@ -23,7 +23,9 @@
 // constexpr void check_arg_id(size_t id);
 
 #include <format>
+
 #include <cassert>
+#include <string_view>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp
@@ -15,7 +15,9 @@
 //                            size_t num_args = 0) noexcept
 
 #include <format>
+
 #include <cassert>
+#include <string_view>
 #include <type_traits>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp
@@ -13,7 +13,9 @@
 // constexpr end() const noexcept;
 
 #include <format>
+
 #include <cassert>
+#include <string_view>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
@@ -23,7 +23,9 @@
 // constexpr size_t next_arg_id();
 
 #include <format>
+
 #include <cassert>
+#include <string_view>
 
 #include "test_macros.h"
 
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp
@@ -24,6 +24,8 @@
 // using wformat_parse_context = basic_format_parse_context<wchar_t>;
 
 #include <format>
+
+#include <string_view>
 #include <type_traits>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
@@ -20,6 +20,8 @@
 // UNSUPPORTED: c++03
 
 #include <memory>
+
+#include <atomic>
 #include <cassert>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
@@ -21,6 +21,8 @@
 // UNSUPPORTED: c++03
 
 #include <memory>
+
+#include <atomic>
 #include <cassert>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
@@ -21,6 +21,8 @@
 // UNSUPPORTED: c++03
 
 #include <memory>
+
+#include <atomic>
 #include <cassert>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
@@ -19,6 +19,8 @@
 // UNSUPPORTED: c++03
 
 #include <memory>
+
+#include <atomic>
 #include <cassert>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
@@ -19,6 +19,8 @@
 // UNSUPPORTED: c++03
 
 #include <memory>
+
+#include <atomic>
 #include <cassert>
 
 #include "test_macros.h"
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
@@ -19,6 +19,8 @@
 // UNSUPPORTED: c++03
 
 #include <memory>
+
+#include <atomic>
 #include <cassert>
 
 #include "test_macros.h"