diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -342,6 +342,7 @@
   __tuple
   __undef_macros
   __utility/as_const.h
+  __utility/auto_cast.h
   __utility/cmp.h
   __utility/decay_copy.h
   __utility/declval.h
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
@@ -14,8 +14,7 @@
 #include <__iterator/readable_traits.h>
 #include <__ranges/enable_borrowed_range.h>
 #include <__utility/as_const.h>
-#include <__utility/decay_copy.h>
-#include <__utility/forward.h>
+#include <__utility/auto_cast.h>
 #include <concepts>
 #include <type_traits>
 
@@ -44,7 +43,7 @@
   concept __member_begin =
     __can_borrow<_Tp> &&
     requires(_Tp&& __t) {
-      { _VSTD::__decay_copy(__t.begin()) } -> input_or_output_iterator;
+      { _LIBCPP_AUTO_CAST(__t.begin()) } -> input_or_output_iterator;
     };
 
   void begin(auto&) = delete;
@@ -56,7 +55,7 @@
     __can_borrow<_Tp> &&
     __class_or_enum<remove_cvref_t<_Tp> > &&
     requires(_Tp && __t) {
-      { _VSTD::__decay_copy(begin(__t)) } -> input_or_output_iterator;
+      { _LIBCPP_AUTO_CAST(begin(__t)) } -> input_or_output_iterator;
     };
 
   struct __fn {
@@ -75,17 +74,17 @@
     template <class _Tp>
     requires __member_begin<_Tp>
     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
-    noexcept(noexcept(_VSTD::__decay_copy(__t.begin())))
+    noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.begin())))
     {
-      return __t.begin();
+      return _LIBCPP_AUTO_CAST(__t.begin());
     }
 
     template <class _Tp>
     requires __unqualified_begin<_Tp>
     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
-    noexcept(noexcept(_VSTD::__decay_copy(begin(__t))))
+    noexcept(noexcept(_LIBCPP_AUTO_CAST(begin(__t))))
     {
-      return begin(__t);
+      return _LIBCPP_AUTO_CAST(begin(__t));
     }
 
     void operator()(auto&&) const = delete;
@@ -108,7 +107,7 @@
     __can_borrow<_Tp> &&
     requires(_Tp&& __t) {
       typename iterator_t<_Tp>;
-      { _VSTD::__decay_copy(_VSTD::forward<_Tp>(__t).end()) } -> sentinel_for<iterator_t<_Tp> >;
+      { _LIBCPP_AUTO_CAST(__t.end()) } -> sentinel_for<iterator_t<_Tp> >;
     };
 
   void end(auto&) = delete;
@@ -121,7 +120,7 @@
     __class_or_enum<remove_cvref_t<_Tp> > &&
     requires(_Tp && __t) {
       typename iterator_t<_Tp>;
-      { _VSTD::__decay_copy(end(_VSTD::forward<_Tp>(__t))) } -> sentinel_for<iterator_t<_Tp> >;
+      { _LIBCPP_AUTO_CAST(end(__t)) } -> sentinel_for<iterator_t<_Tp> >;
     };
 
   class __fn {
@@ -140,17 +139,17 @@
     template <class _Tp>
     requires __member_end<_Tp>
     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
-    noexcept(noexcept(_VSTD::__decay_copy(__t.end())))
+    noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.end())))
     {
-      return _VSTD::forward<_Tp>(__t).end();
+      return _LIBCPP_AUTO_CAST(__t.end());
     }
 
     template <class _Tp>
     requires __unqualified_end<_Tp>
     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
-    noexcept(noexcept(_VSTD::__decay_copy(end(__t))))
+    noexcept(noexcept(_LIBCPP_AUTO_CAST(end(__t))))
     {
-      return end(__t);
+      return _LIBCPP_AUTO_CAST(end(__t));
     }
 
     void operator()(auto&&) const = delete;
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
@@ -13,8 +13,7 @@
 #include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__ranges/access.h>
-#include <__utility/decay_copy.h>
-#include <__utility/forward.h>
+#include <__utility/auto_cast.h>
 #include <concepts>
 #include <type_traits>
 
@@ -26,7 +25,6 @@
 
 #if !defined(_LIBCPP_HAS_NO_RANGES)
 
-// clang-format off
 namespace ranges {
 template<class>
 inline constexpr bool disable_sized_range = false;
@@ -41,7 +39,7 @@
 
   template <class _Tp>
   concept __member_size = __size_enabled<_Tp> && requires(_Tp&& __t) {
-    { _VSTD::__decay_copy(_VSTD::forward<_Tp>(__t).size()) } -> __integer_like;
+    { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like;
   };
 
   template <class _Tp>
@@ -50,7 +48,7 @@
     !__member_size<_Tp> &&
     __class_or_enum<remove_cvref_t<_Tp>> &&
     requires(_Tp&& __t) {
-      { _VSTD::__decay_copy(size(_VSTD::forward<_Tp>(__t))) } -> __integer_like;
+      { _LIBCPP_AUTO_CAST(size(__t)) } -> __integer_like;
     };
 
   template <class _Tp>
@@ -76,14 +74,14 @@
 
     template <__member_size _Tp>
     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const
-        noexcept(noexcept(_VSTD::forward<_Tp>(__t).size())) {
-      return _VSTD::forward<_Tp>(__t).size();
+        noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.size()))) {
+      return _LIBCPP_AUTO_CAST(__t.size());
     }
 
     template <__unqualified_size _Tp>
     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const
-        noexcept(noexcept(size(_VSTD::forward<_Tp>(__t)))) {
-      return size(_VSTD::forward<_Tp>(__t));
+        noexcept(noexcept(_LIBCPP_AUTO_CAST(size(__t)))) {
+      return _LIBCPP_AUTO_CAST(size(__t));
     }
 
     template<__difference _Tp>
@@ -118,8 +116,6 @@
 } // namespace __cpo
 } // namespace ranges
 
-// clang-format off
-
 #endif // !defined(_LIBCPP_HAS_NO_RANGES)
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__utility/auto_cast.h b/libcxx/include/__utility/auto_cast.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__utility/auto_cast.h
@@ -0,0 +1,22 @@
+// -*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_AUTO_CAST_H
+#define _LIBCPP___UTILITY_AUTO_CAST_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#define _LIBCPP_AUTO_CAST(expr) static_cast<decay_t<decltype((expr))>>(expr)
+
+#endif // _LIBCPP___UTILITY_AUTO_CAST_H
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -894,6 +894,7 @@
 
     module __utility {
       module as_const            { private header "__utility/as_const.h" }
+      module auto_cast           { private header "__utility/auto_cast.h" }
       module cmp                 { private header "__utility/cmp.h" }
       module decay_copy          { private header "__utility/decay_copy.h" }
       module declval             { private header "__utility/declval.h" }
diff --git a/libcxx/include/utility b/libcxx/include/utility
--- a/libcxx/include/utility
+++ b/libcxx/include/utility
@@ -218,7 +218,9 @@
 #include <__debug>
 #include <__tuple>
 #include <__utility/as_const.h>
+#include <__utility/auto_cast.h>
 #include <__utility/cmp.h>
+#include <__utility/decay_copy.h>
 #include <__utility/declval.h>
 #include <__utility/exchange.h>
 #include <__utility/forward.h>
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/utility/auto_cast.module.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/utility/auto_cast.module.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/utility/auto_cast.module.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__utility/auto_cast.h'}}
+#include <__utility/auto_cast.h>
diff --git a/libcxx/test/std/ranges/range.access/range.access.begin/begin.pass.cpp b/libcxx/test/std/ranges/range.access/range.access.begin/begin.pass.cpp
--- a/libcxx/test/std/ranges/range.access/range.access.begin/begin.pass.cpp
+++ b/libcxx/test/std/ranges/range.access/range.access.begin/begin.pass.cpp
@@ -245,28 +245,27 @@
 ASSERT_NOEXCEPT(std::ranges::begin(std::declval<int (&)[10]>()));
 ASSERT_NOEXCEPT(std::ranges::cbegin(std::declval<int (&)[10]>()));
 
-template<class T>
 struct NoThrowMemberBegin {
-  T begin() const noexcept;
-};
-ASSERT_NOEXCEPT(std::ranges::begin(std::declval<NoThrowMemberBegin<int*>&>()));
-ASSERT_NOEXCEPT(std::ranges::cbegin(std::declval<NoThrowMemberBegin<int*>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::begin(std::declval<NoThrowMemberBegin<ThrowingIterator<int>>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::cbegin(std::declval<NoThrowMemberBegin<ThrowingIterator<int>>&>()));
+  ThrowingIterator<int> begin() const noexcept; // auto(t.begin()) doesn't throw
+} ntmb;
+static_assert(noexcept(std::ranges::begin(ntmb)));
+static_assert(noexcept(std::ranges::cbegin(ntmb)));
 
-template<class T>
 struct NoThrowADLBegin {
-  friend T begin(NoThrowADLBegin&) noexcept { return T{}; }
-  friend T begin(NoThrowADLBegin const&) noexcept { return T{}; }
-};
-ASSERT_NOEXCEPT(std::ranges::begin(std::declval<NoThrowADLBegin<int*>&>()));
-ASSERT_NOEXCEPT(std::ranges::cbegin(std::declval<NoThrowADLBegin<int*>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::begin(std::declval<NoThrowADLBegin<ThrowingIterator<int>>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::cbegin(std::declval<NoThrowADLBegin<ThrowingIterator<int>>&>()));
+  friend ThrowingIterator<int> begin(NoThrowADLBegin&) noexcept;  // auto(begin(t)) doesn't throw
+  friend ThrowingIterator<int> begin(const NoThrowADLBegin&) noexcept;
+} ntab;
+static_assert(noexcept(std::ranges::begin(ntab)));
+static_assert(noexcept(std::ranges::cbegin(ntab)));
+
+struct NoThrowMemberBeginReturnsRef {
+  ThrowingIterator<int>& begin() const noexcept; // auto(t.begin()) may throw
+} ntmbrr;
+static_assert(!noexcept(std::ranges::begin(ntmbrr)));
+static_assert(!noexcept(std::ranges::cbegin(ntmbrr)));
 
 struct BeginReturnsArrayRef {
     auto begin() const noexcept -> int(&)[10];
-    auto end() const noexcept -> int(&)[10];
 } brar;
 static_assert(noexcept(std::ranges::begin(brar)));
 static_assert(noexcept(std::ranges::cbegin(brar)));
diff --git a/libcxx/test/std/ranges/range.access/range.access.end/end.pass.cpp b/libcxx/test/std/ranges/range.access/range.access.end/end.pass.cpp
--- a/libcxx/test/std/ranges/range.access/range.access.end/end.pass.cpp
+++ b/libcxx/test/std/ranges/range.access/range.access.end/end.pass.cpp
@@ -277,34 +277,34 @@
 ASSERT_NOEXCEPT(std::ranges::end(std::declval<int (&)[10]>()));
 ASSERT_NOEXCEPT(std::ranges::cend(std::declval<int (&)[10]>()));
 
-template<class T>
 struct NoThrowMemberEnd {
-  T begin() const;
-  T end() const noexcept;
-};
-ASSERT_NOEXCEPT(std::ranges::end(std::declval<NoThrowMemberEnd<int*>&>()));
-ASSERT_NOEXCEPT(std::ranges::cend(std::declval<NoThrowMemberEnd<int*>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::end(std::declval<NoThrowMemberEnd<ThrowingIterator<int>>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::cend(std::declval<NoThrowMemberEnd<ThrowingIterator<int>>&>()));
+  ThrowingIterator<int> begin() const;
+  ThrowingIterator<int> end() const noexcept; // auto(t.end()) doesn't throw
+} ntme;
+static_assert(noexcept(std::ranges::end(ntme)));
+static_assert(noexcept(std::ranges::cend(ntme)));
 
-template<class T>
 struct NoThrowADLEnd {
-  T begin() const;
-  friend T end(NoThrowADLEnd&) noexcept { return T{}; }
-  friend T end(NoThrowADLEnd const&) noexcept { return T{}; }
-};
-ASSERT_NOEXCEPT(std::ranges::end(std::declval<NoThrowADLEnd<int*>&>()));
-ASSERT_NOEXCEPT(std::ranges::cend(std::declval<NoThrowADLEnd<int*>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::end(std::declval<NoThrowADLEnd<ThrowingIterator<int>>&>()));
-ASSERT_NOT_NOEXCEPT(std::ranges::cend(std::declval<NoThrowADLEnd<ThrowingIterator<int>>&>()));
-
-struct BeginReturnsArrayRef {
+  ThrowingIterator<int> begin() const;
+  friend ThrowingIterator<int> end(NoThrowADLEnd&) noexcept;  // auto(end(t)) doesn't throw
+  friend ThrowingIterator<int> end(const NoThrowADLEnd&) noexcept;
+} ntae;
+static_assert(noexcept(std::ranges::end(ntae)));
+static_assert(noexcept(std::ranges::cend(ntae)));
+
+struct NoThrowMemberEndReturnsRef {
+  ThrowingIterator<int> begin() const;
+  ThrowingIterator<int>& end() const noexcept; // auto(t.end()) may throw
+} ntmerr;
+static_assert(!noexcept(std::ranges::end(ntmerr)));
+static_assert(!noexcept(std::ranges::cend(ntmerr)));
+
+struct EndReturnsArrayRef {
     auto begin() const noexcept -> int(&)[10];
     auto end() const noexcept -> int(&)[10];
-} brar;
-static_assert(noexcept(std::ranges::end(brar)));
-static_assert(noexcept(std::ranges::cend(brar)));
-
+} erar;
+static_assert(noexcept(std::ranges::end(erar)));
+static_assert(noexcept(std::ranges::cend(erar)));
 
 int main(int, char**) {
   testArray();
diff --git a/libcxx/test/std/ranges/range.access/range.prim/size.pass.cpp b/libcxx/test/std/ranges/range.access/range.prim/size.pass.cpp
--- a/libcxx/test/std/ranges/range.access/range.prim/size.pass.cpp
+++ b/libcxx/test/std/ranges/range.access/range.prim/size.pass.cpp
@@ -124,7 +124,7 @@
 bool constexpr testHasSizeFunction() {
   assert(std::ranges::size(SizeFunction()) == 42);
   ASSERT_SAME_TYPE(decltype(std::ranges::size(SizeFunction())), size_t);
-  assert(std::ranges::size(MoveOnlySizeFunction()) == 42);
+  static_assert(!std::is_invocable_v<RangeSizeT, MoveOnlySizeFunction>);
   assert(std::ranges::size(EnumSizeFunction()) == 42);
   assert(std::ranges::size(SizeFunctionConst()) == 42);