diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -38,6 +38,7 @@
   __ranges/begin.h
   __ranges/cbegin.h
   __ranges/cend.h
+  __ranges/concepts.h
   __ranges/end.h
   __ranges/enable_borrowed_range.h
   __split_buffer
diff --git a/libcxx/include/__ranges/concepts.h b/libcxx/include/__ranges/concepts.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__ranges/concepts.h
@@ -0,0 +1,68 @@
+// -*- C++ -*-
+//===--------------------- __ranges/concepts.h ----------------------------===//
+//
+// 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_RANGES_CONCEPTS_H
+#define _LIBCPP_RANGES_CONCEPTS_H
+
+#include <__config>
+#include <__ranges/begin.h>
+#include <__ranges/end.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// clang-format off
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  // [range.range]
+  template <class _Tp>
+  concept range = requires(_Tp& __t) {
+    ranges::begin(__t); // sometimes equality-preserving
+    ranges::end(__t);
+  };
+
+  // `iterator_t` defined in <__ranges/begin.h>
+
+  template <range _Rp>
+  using sentinel_t = decltype(ranges::end(declval<_Rp&>()));
+
+  template <range _Rp>
+  using range_difference_t = iter_difference_t<iterator_t<_Rp> >;
+
+  template <range _Rp>
+  using range_value_t = iter_value_t<iterator_t<_Rp> >;
+
+  template <range _Rp>
+  using range_reference_t = iter_reference_t<iterator_t<_Rp> >;
+
+  template <range _Rp>
+  using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<_Rp> >;
+
+  // [range.refinements], other range refinements
+  template <class _Tp>
+  concept common_range = range<_Tp> && same_as<iterator_t<_Tp>, sentinel_t<_Tp> >;
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+// clang-format on
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_RANGES_CONCEPTS_H
diff --git a/libcxx/include/ranges b/libcxx/include/ranges
--- a/libcxx/include/ranges
+++ b/libcxx/include/ranges
@@ -26,11 +26,30 @@
   }
 
   // [range.range], ranges
+  template<class T>
+    concept range = see below;
+
   template<class T>
     inline constexpr bool enable_borrowed_range = false;
 
   template<class T>
     using iterator_t = decltype(ranges::begin(declval<T&>()));
+  template<class T>
+    using iterator_t = decltype(ranges::begin(declval<T&>()));
+  template<range R>
+    using sentinel_t = decltype(ranges::end(declval<R&>()));
+  template<range R>
+    using range_difference_t = iter_difference_t<iterator_t<R>>;
+  template<range R>
+    using range_value_t = iter_value_t<iterator_t<R>>;
+  template<range R>
+    using range_reference_t = iter_reference_t<iterator_t<R>>;
+  template<range R>
+    using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<R>>;
+
+  // [range.refinements], other range refinements
+  template <class _Tp>
+    concept common_range = see below;
 }
 
 */
@@ -39,6 +58,8 @@
 #include <__ranges/begin.h>
 #include <__ranges/cbegin.h>
 #include <__ranges/cend.h>
+#include <__ranges/concepts.h>
+#include <__ranges/end.h>
 #include <__ranges/enable_borrowed_range.h>
 #include <__ranges/end.h>
 #include <compare>          // Required by the standard.
diff --git a/libcxx/test/std/containers/associative/map/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/associative/map/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/associative/map/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/associative/map/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/associative/multimap/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/associative/multimap/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/associative/multimap/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/associative/multimap/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/associative/multiset/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/associative/multiset/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/associative/multiset/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/associative/multiset/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/views/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/associative/set/range_concept.conformance.compile.pass.cpp
copy from libcxx/test/std/containers/views/range_concept_conformance.compile.pass.cpp
copy to libcxx/test/std/containers/associative/set/range_concept.conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/views/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/associative/set/range_concept.conformance.compile.pass.cpp
@@ -9,16 +9,12 @@
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-no-concepts
 // UNSUPPORTED: gcc-10
-// XFAIL: msvc && clang
 
-// span
+// set
 
-#include <span>
+#include <set>
 
-#include <concepts>
 #include <ranges>
 
-using range = std::span<int>;
-namespace stdr = std::ranges;
-
-static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::ranges::range<std::set<int> >);
+static_assert(std::ranges::range<std::set<int> const>);
diff --git a/libcxx/test/std/containers/sequences/array/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/sequences/array/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/sequences/array/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/sequences/deque/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/sequences/deque/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/sequences/deque/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/deque/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/sequences/forwardlist/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/sequences/forwardlist/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/sequences/forwardlist/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/forwardlist/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/sequences/list/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/sequences/list/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/sequences/list/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/list/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/sequences/vector.bool/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/sequences/vector.bool/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/sequences/vector.bool/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector.bool/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/sequences/vector/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/sequences/vector/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/sequences/vector/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/vector/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/unord/unord.map/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/unord/unord.map/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.map/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.map/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/unord/unord.multimap/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/unord/unord.multimap/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multimap/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multimap/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/unord/unord.multiset/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/unord/unord.multiset/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.multiset/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.multiset/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/unord/unord.set/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/unord/unord.set/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/unord/unord.set/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/unord/unord.set/range_concept_conformance.compile.pass.cpp
@@ -22,4 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
 static_assert(std::same_as<stdr::iterator_t<range const>, range::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::const_iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/containers/views/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/containers/views/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/containers/views/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/containers/views/range_concept_conformance.compile.pass.cpp
@@ -22,3 +22,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::iterator_t<range const>, range::iterator>);
+static_assert(stdr::common_range<range>);
+
+static_assert(std::same_as<stdr::sentinel_t<range>, range::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<range const>, range::iterator>);
+static_assert(stdr::common_range<range const>);
diff --git a/libcxx/test/std/input.output/filesystems/class.directory_iterator/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/input.output/filesystems/class.directory_iterator/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/class.directory_iterator/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.directory_iterator/range_concept_conformance.compile.pass.cpp
@@ -9,7 +9,7 @@
 // UNSUPPORTED: c++03, c++11, c++14, c++17
 // UNSUPPORTED: libcpp-no-concepts
 // UNSUPPORTED: gcc-10
-// XFAIL: msvc && clang
+// XFAIL: *
 
 // directory_iterator, recursive_directory_iterator
 
@@ -21,6 +21,17 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<fs::directory_iterator>, fs::directory_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<fs::directory_iterator>, fs::directory_iterator>);
+static_assert(stdr::common_range<fs::directory_iterator>);
+
 static_assert(std::same_as<stdr::iterator_t<fs::directory_iterator const>, fs::directory_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<fs::directory_iterator const>, fs::directory_iterator>);
+static_assert(stdr::common_range<fs::directory_iterator const>);
+
 static_assert(std::same_as<stdr::iterator_t<fs::recursive_directory_iterator>, fs::recursive_directory_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<fs::recursive_directory_iterator>, fs::recursive_directory_iterator>);
+static_assert(stdr::common_range<fs::recursive_directory_iterator>);
+
 static_assert(std::same_as<stdr::iterator_t<fs::recursive_directory_iterator const>, fs::recursive_directory_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<fs::recursive_directory_iterator const>, fs::recursive_directory_iterator>);
+static_assert(stdr::common_range<fs::recursive_directory_iterator const>);
diff --git a/libcxx/test/std/input.output/filesystems/class.path/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/input.output/filesystems/class.path/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/class.path/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/class.path/range_concept_conformance.compile.pass.cpp
@@ -21,4 +21,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<fs::path>, fs::path::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<fs::path>, fs::path::iterator>);
+static_assert(stdr::common_range<fs::path>);
+
 static_assert(std::same_as<stdr::iterator_t<fs::path const>, fs::path::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<fs::path const>, fs::path::const_iterator>);
+static_assert(stdr::common_range<fs::path const>);
diff --git a/libcxx/test/std/ranges/range.range/helper_aliases.compile.pass.cpp b/libcxx/test/std/ranges/range.range/helper_aliases.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.range/helper_aliases.compile.pass.cpp
@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// 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: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+// UNSUPPORTED: gcc-10
+
+// template<range R>
+// using range_difference_t = iter_difference_t<iterator_t<R>>;
+
+// template<range R>
+// using range_value_t = iter_value_t<iterator_t<R>>;
+
+// template<range R>
+// using range_reference_t = iter_reference_t<iterator_t<R>>;
+
+// template<range R>
+// using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<R>>;
+
+#include <ranges>
+
+#include <concepts>
+
+#include "test_range.h"
+
+namespace stdr = std::ranges;
+
+static_assert(std::same_as<stdr::range_difference_t<test_range<> >, std::iter_difference_t<int*> >);
+static_assert(std::same_as<stdr::range_value_t<test_range<> >, std::iter_value_t<int*> >);
+static_assert(std::same_as<stdr::range_reference_t<test_range<> >, std::iter_reference_t<int*> >);
+static_assert(std::same_as<stdr::range_rvalue_reference_t<test_range<> >, std::iter_rvalue_reference_t<int*> >);
diff --git a/libcxx/test/std/ranges/range.range/range.compile.pass.cpp b/libcxx/test/std/ranges/range.range/range.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.range/range.compile.pass.cpp
@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// 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: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+// UNSUPPORTED: gcc-10
+
+// template<class T>
+// concept range;
+
+#include <ranges>
+
+#include <vector>
+
+#include "test_range.h"
+
+namespace stdr = std::ranges;
+
+static_assert(stdr::range<test_range<> >);
+
+struct incompatible_iterators {
+  int* begin();
+  long* end();
+};
+static_assert(!stdr::range<incompatible_iterators>);
+
+struct int_begin_int_end {
+  int begin();
+  int end();
+};
+static_assert(!stdr::range<int_begin_int_end>);
+
+struct iterator_begin_int_end {
+  int* begin();
+  int end();
+};
+static_assert(!stdr::range<iterator_begin_int_end>);
+
+struct int_begin_iterator_end {
+  int begin();
+  int* end();
+};
+static_assert(!stdr::range<int_begin_iterator_end>);
diff --git a/libcxx/test/std/ranges/range.range/sentinel_t.compile.pass.cpp b/libcxx/test/std/ranges/range.range/sentinel_t.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.range/sentinel_t.compile.pass.cpp
@@ -0,0 +1,30 @@
+//===----------------------------------------------------------------------===//
+//
+// 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: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+// UNSUPPORTED: gcc-10
+
+// template<range _Rp>
+// using sentinel_t = decltype(ranges::end(declval<_Rp&>()));
+
+#include <ranges>
+
+#include <concepts>
+
+#include "test_iterators.h"
+#include "test_range.h"
+
+namespace stdr = std::ranges;
+
+static_assert(std::same_as<stdr::sentinel_t<test_range<> >, sentinel>);
+static_assert(std::same_as<stdr::sentinel_t<test_range<> const>, sentinel>);
+static_assert(std::same_as<stdr::sentinel_t<test_non_const_range<> >, sentinel>);
+static_assert(std::same_as<stdr::sentinel_t<test_common_range<> >, input_iterator<int*> >);
+static_assert(std::same_as<stdr::sentinel_t<test_common_range<> const>, input_iterator<int const*> >);
+static_assert(std::same_as<stdr::sentinel_t<test_non_const_common_range<> >, input_iterator<int*> >);
diff --git a/libcxx/test/std/ranges/range.refinements/common_range.compile.pass.cpp b/libcxx/test/std/ranges/range.refinements/common_range.compile.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/ranges/range.refinements/common_range.compile.pass.cpp
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// 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: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+// XFAIL: msvc && clang
+
+// template<class T>
+// concept common_range;
+
+#include <ranges>
+
+#include "test_iterators.h"
+#include "test_range.h"
+
+namespace stdr = std::ranges;
+
+static_assert(!stdr::common_range<test_range<input_iterator> >);
+static_assert(!stdr::common_range<test_range<input_iterator> const>);
+
+static_assert(!stdr::common_range<test_non_const_range<input_iterator> >);
+static_assert(!stdr::common_range<test_non_const_range<input_iterator> const>);
+
+static_assert(stdr::common_range<test_common_range<input_iterator> >);
+static_assert(stdr::common_range<test_common_range<input_iterator> const>);
+
+static_assert(stdr::common_range<test_non_const_common_range<input_iterator> >);
+static_assert(!stdr::common_range<test_non_const_common_range<input_iterator> const>);
+
+struct subtly_not_common {
+  int* begin() const;
+  int const* end() const;
+};
+static_assert(stdr::range<subtly_not_common> && !stdr::common_range<subtly_not_common>);
+static_assert(stdr::range<subtly_not_common const> && !stdr::common_range<subtly_not_common const>);
+
+struct common_range_non_const_only {
+  int* begin() const;
+  int* end();
+  int const* end() const;
+};
+static_assert(stdr::range<common_range_non_const_only>&& stdr::common_range<common_range_non_const_only>);
+static_assert(stdr::range<common_range_non_const_only const> && !stdr::common_range<common_range_non_const_only const>);
+
+struct common_range_const_only {
+  int* begin();
+  int const* begin() const;
+  int const* end() const;
+};
+static_assert(stdr::range<common_range_const_only> && !stdr::common_range<common_range_const_only>);
+static_assert(stdr::range<common_range_const_only const>&& stdr::common_range<common_range_const_only const>);
diff --git a/libcxx/test/std/re/re.results/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/re/re.results/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/re/re.results/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/re/re.results/range_concept_conformance.compile.pass.cpp
@@ -21,4 +21,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<std::cmatch>, std::cmatch::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<std::cmatch>, std::cmatch::iterator>);
+static_assert(stdr::common_range<std::cmatch>);
+
 static_assert(std::same_as<stdr::iterator_t<std::cmatch const>, std::cmatch::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<std::cmatch const>, std::cmatch::const_iterator>);
+static_assert(stdr::common_range<std::cmatch const>);
diff --git a/libcxx/test/std/strings/basic.string/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/strings/basic.string/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/strings/basic.string/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/range_concept_conformance.compile.pass.cpp
@@ -21,4 +21,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<std::string>, std::string::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<std::string>, std::string::iterator>);
+static_assert(stdr::common_range<std::string>);
+
 static_assert(std::same_as<stdr::iterator_t<std::string const>, std::string::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<std::string const>, std::string::const_iterator>);
+static_assert(stdr::common_range<std::string const>);
diff --git a/libcxx/test/std/strings/string.view/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/strings/string.view/range_concept_conformance.compile.pass.cpp
--- a/libcxx/test/std/strings/string.view/range_concept_conformance.compile.pass.cpp
+++ b/libcxx/test/std/strings/string.view/range_concept_conformance.compile.pass.cpp
@@ -21,4 +21,9 @@
 namespace stdr = std::ranges;
 
 static_assert(std::same_as<stdr::iterator_t<std::string_view>, std::string_view::iterator>);
+static_assert(std::same_as<stdr::sentinel_t<std::string_view>, std::string_view::iterator>);
+static_assert(stdr::common_range<std::string_view>);
+
 static_assert(std::same_as<stdr::iterator_t<std::string_view const>, std::string_view::const_iterator>);
+static_assert(std::same_as<stdr::sentinel_t<std::string_view const>, std::string_view::const_iterator>);
+static_assert(stdr::common_range<std::string_view const>);
diff --git a/libcxx/test/support/test_range.h b/libcxx/test/support/test_range.h
--- a/libcxx/test/support/test_range.h
+++ b/libcxx/test/support/test_range.h
@@ -22,7 +22,7 @@
 };
 
 // clang-format off
-template <template <class...> class I>
+template <template <class...> class I = input_iterator>
 requires std::input_or_output_iterator<I<int*> >
 struct test_range {
   I<int*> begin();
@@ -31,23 +31,23 @@
   sentinel end() const;
 };
 
-template <template <class...> class I>
+template <template <class...> class I = input_iterator>
 requires std::input_or_output_iterator<I<int*> >
 struct test_non_const_range {
   I<int*> begin();
   sentinel end();
 };
 
-template <template <class...> class I>
+template <template <class...> class I = input_iterator>
 requires std::input_or_output_iterator<I<int*> >
 struct test_common_range {
   I<int*> begin();
   I<int const*> begin() const;
   I<int*> end();
-  I<int*> end() const;
+  I<int const*> end() const;
 };
 
-template <template <class...> class I>
+template <template <class...> class I = input_iterator>
 requires std::input_or_output_iterator<I<int*> >
 struct test_non_const_common_range {
   I<int*> begin();