diff --git a/libcxx/include/__config b/libcxx/include/__config
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1455,6 +1455,24 @@
 #define _LIBCPP_FORMAT_PRINTF(a, b)
 #endif
 
+#if !defined(__clang__) || !__building_module(std_config)
+#  define _LIBCPP_HAS_NO_MODULES
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  if defined(_LIBCPP_COMPILER_MSVC)
+#    define _LIBCPP_PUSH_DETAIL_HEADER_PASS \
+       __pragma(push_macro("_LIBCPP_DETAIL_HEADERS_ALLOWED"))
+#    define _LIBCPP_POP_DETAIL_HEADER_PASS  \
+       __pragma(pop_macro("_LIBCPP_DETAIL_HEADERS_ALLOWED"))
+#  else
+#    define _LIBCPP_PUSH_DETAIL_HEADER_PASS        \
+       _Pragma("push_macro(\"_LIBCPP_DETAIL_HEADERS_ALLOWED\")")
+#    define _LIBCPP_POP_DETAIL_HEADER_PASS         \
+       _Pragma("pop_macro(\"_LIBCPP_DETAIL_HEADERS_ALLOWED\")")
+#  endif
+#endif // defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+
 #endif // __cplusplus
 
 #endif // _LIBCPP_CONFIG
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
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_ACCESS_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/access.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/readable_traits.h>
 #include <__ranges/enable_borrowed_range.h>
@@ -18,6 +27,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/__ranges/all.h b/libcxx/include/__ranges/all.h
--- a/libcxx/include/__ranges/all.h
+++ b/libcxx/include/__ranges/all.h
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_ALL_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/all.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__ranges/access.h>
@@ -21,6 +30,11 @@
 #include <__utility/forward.h>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
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
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_CONCEPTS_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/concepts.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
 #include <__iterator/iter_move.h>
@@ -23,6 +32,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/__ranges/copyable_box.h b/libcxx/include/__ranges/copyable_box.h
--- a/libcxx/include/__ranges/copyable_box.h
+++ b/libcxx/include/__ranges/copyable_box.h
@@ -11,6 +11,15 @@
 #define _LIBCPP___RANGES_COPYABLE_BOX_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/copyable_box.h> is a libc++ detail header and can't be directly included by users.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__memory/addressof.h>
 #include <__memory/construct_at.h>
 #include <__utility/move.h>
@@ -18,6 +27,11 @@
 #include <optional>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
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
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_DATA_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/data.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__memory/pointer_traits.h>
@@ -18,6 +27,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/__ranges/drop_view.h b/libcxx/include/__ranges/drop_view.h
--- a/libcxx/include/__ranges/drop_view.h
+++ b/libcxx/include/__ranges/drop_view.h
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_DROP_VIEW_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/drop_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/next.h>
@@ -22,6 +31,11 @@
 #include <optional>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
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
@@ -10,12 +10,26 @@
 #define _LIBCPP___RANGES_EMPTY_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/empty.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__ranges/access.h>
 #include <__ranges/size.h>
 #include <__utility/forward.h>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/__ranges/empty_view.h b/libcxx/include/__ranges/empty_view.h
--- a/libcxx/include/__ranges/empty_view.h
+++ b/libcxx/include/__ranges/empty_view.h
@@ -10,9 +10,23 @@
 #define _LIBCPP___RANGES_EMPTY_VIEW_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/empty_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__ranges/view_interface.h>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/__ranges/enable_borrowed_range.h b/libcxx/include/__ranges/enable_borrowed_range.h
--- a/libcxx/include/__ranges/enable_borrowed_range.h
+++ b/libcxx/include/__ranges/enable_borrowed_range.h
@@ -15,6 +15,9 @@
 // <span> and <string_view>.
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/enable_borrowed_range.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
diff --git a/libcxx/include/__ranges/enable_view.h b/libcxx/include/__ranges/enable_view.h
--- a/libcxx/include/__ranges/enable_view.h
+++ b/libcxx/include/__ranges/enable_view.h
@@ -11,6 +11,10 @@
 #define _LIBCPP___RANGES_ENABLE_VIEW_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/enable_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
 #include <concepts>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/__ranges/ref_view.h b/libcxx/include/__ranges/ref_view.h
--- a/libcxx/include/__ranges/ref_view.h
+++ b/libcxx/include/__ranges/ref_view.h
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_REF_VIEW_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/ref_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
 #include <__iterator/iterator_traits.h>
@@ -23,6 +32,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
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
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_SIZE_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/size.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__ranges/access.h>
@@ -18,6 +27,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/__ranges/subrange.h b/libcxx/include/__ranges/subrange.h
--- a/libcxx/include/__ranges/subrange.h
+++ b/libcxx/include/__ranges/subrange.h
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_SUBRANGE_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/subrange.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/incrementable_traits.h>
 #include <__iterator/iterator_traits.h>
@@ -22,6 +31,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/__ranges/transform_view.h b/libcxx/include/__ranges/transform_view.h
--- a/libcxx/include/__ranges/transform_view.h
+++ b/libcxx/include/__ranges/transform_view.h
@@ -10,6 +10,16 @@
 #define _LIBCPP___RANGES_TRANSFORM_VIEW_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/transform_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
+#include <__iterator/iterator_traits.h>
 #include <__iterator/concepts.h>
 #include <__iterator/iter_swap.h>
 #include <__iterator/iterator_traits.h>
@@ -23,6 +33,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
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
@@ -10,6 +10,15 @@
 #define _LIBCPP___RANGES_VIEW_INTERFACE_H
 
 #include <__config>
+#if defined(_LIBCPP_HAS_NO_MODULES) && !defined(_LIBCPP_DETAIL_HEADERS_ALLOWED)
+#  error <__ranges/view_interface.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/prev.h>
@@ -21,6 +30,11 @@
 #include <concepts>
 #include <type_traits>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/iterator b/libcxx/include/iterator
--- a/libcxx/include/iterator
+++ b/libcxx/include/iterator
@@ -559,7 +559,11 @@
 */
 
 #include <__config>
-#include <__debug>
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__functional_base>
 #include <__iterator/access.h>
 #include <__iterator/advance.h>
@@ -600,6 +604,11 @@
 #include <type_traits>
 #include <version>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/ranges b/libcxx/include/ranges
--- a/libcxx/include/ranges
+++ b/libcxx/include/ranges
@@ -132,6 +132,11 @@
 */
 
 #include <__config>
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__ranges/access.h>
 #include <__ranges/all.h>
 #include <__ranges/concepts.h>
@@ -152,6 +157,11 @@
 #include <type_traits>
 #include <version>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+   _LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/span b/libcxx/include/span
--- a/libcxx/include/span
+++ b/libcxx/include/span
@@ -128,6 +128,11 @@
 */
 
 #include <__config>
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__debug>
 #include <__iterator/wrap_iter.h>
 #include <__ranges/enable_borrowed_range.h>
@@ -139,6 +144,11 @@
 #include <type_traits>  // for remove_cv, etc
 #include <version>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+_LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/include/string_view b/libcxx/include/string_view
--- a/libcxx/include/string_view
+++ b/libcxx/include/string_view
@@ -185,6 +185,11 @@
 */
 
 #include <__config>
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+   _LIBCPP_PUSH_DETAIL_HEADER_PASS
+#  define _LIBCPP_DETAIL_HEADERS_ALLOWED
+#endif
+
 #include <__debug>
 #include <__ranges/enable_borrowed_range.h>
 #include <__ranges/enable_view.h>
@@ -197,6 +202,11 @@
 #include <stdexcept>
 #include <version>
 
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#undef _LIBCPP_DETAIL_HEADERS_ALLOWED
+_LIBCPP_POP_DETAIL_HEADER_PASS
+#endif
+
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/access.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/access.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/access.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/access.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/access.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/all.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/all.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/all.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/all.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/all.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/concepts.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/concepts.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/concepts.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/concepts.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/concepts.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/copyable_box.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/copyable_box.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/copyable_box.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/copyable_box.h> is a libc++ detail header and can't be directly included by users.}}
+#include <__ranges/copyable_box.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/data.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/data.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/data.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/data.h> is a libc++ detail header and can't be directly included by users.}}
+#include <__ranges/data.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/drop_view.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/drop_view.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/drop_view.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/drop_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/drop_view.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/empty.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/empty.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/empty.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/empty.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/empty.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/empty_view.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/empty_view.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/empty_view.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/empty_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/empty_view.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/enable_borrowed_range.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/enable_borrowed_range.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/enable_borrowed_range.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/enable_borrowed_range.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/enable_borrowed_range.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/enable_view.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/enable_view.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/enable_view.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/enable_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/enable_view.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/ref_view.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/ref_view.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/ref_view.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/ref_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/ref_view.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/size.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/size.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/size.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/size.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/size.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/subrange.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/subrange.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/subrange.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/subrange.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/subrange.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/transform_view.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/transform_view.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/transform_view.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/transform_view.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/transform_view.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/view_interface.header.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/view_interface.header.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/view_interface.header.verify.cpp
@@ -0,0 +1,13 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: modules-build
+
+// expected-error@*:* {{<__ranges/view_interface.h> is a libc++ detail header and can't be directly included by users. Please '#include <ranges>' instead.}}
+#include <__ranges/view_interface.h>