[libcxx-commits] [libcxx] 0f4b41e - [libcxx][ranges] Add ranges::take_view.

via libcxx-commits libcxx-commits at lists.llvm.org
Wed Jul 28 12:14:37 PDT 2021


Author: zoecarver
Date: 2021-07-28T12:14:21-07:00
New Revision: 0f4b41e038537ab2ab6fa2aa048e55c28a03ab68

URL: https://github.com/llvm/llvm-project/commit/0f4b41e038537ab2ab6fa2aa048e55c28a03ab68
DIFF: https://github.com/llvm/llvm-project/commit/0f4b41e038537ab2ab6fa2aa048e55c28a03ab68.diff

LOG: [libcxx][ranges] Add ranges::take_view.

Differential Revision: https://reviews.llvm.org/D106507

Added: 
    libcxx/include/__ranges/take_view.h
    libcxx/test/libcxx/diagnostics/detail.headers/ranges/take_view.module.verify.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/base.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/begin.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/borrowing.compile.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/ctad.compile.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/ctor.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/end.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/range_concept_conformance.compile.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/sentinel/base.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/sentinel/ctor.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/sentinel/eq.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/size.pass.cpp
    libcxx/test/std/ranges/range.adaptors/range.take/types.h

Modified: 
    libcxx/docs/Status/RangesPaper.csv
    libcxx/include/CMakeLists.txt
    libcxx/include/module.modulemap
    libcxx/include/ranges
    libcxx/test/std/ranges/range.adaptors/range.transform/ctad.compile.pass.cpp
    libcxx/test/support/test_range.h

Removed: 
    


################################################################################
diff  --git a/libcxx/docs/Status/RangesPaper.csv b/libcxx/docs/Status/RangesPaper.csv
index a7d289706691c..aede9e6fafd54 100644
--- a/libcxx/docs/Status/RangesPaper.csv
+++ b/libcxx/docs/Status/RangesPaper.csv
@@ -139,7 +139,7 @@ Section,Description,Dependencies,Assignee,Complete
 `[range.filter] <http://wg21.link/range.filter>`_,filter_view,[range.all],Louis Dionne,Not started
 `[range.transform] <http://wg21.link/range.transform>`_,`transform_view <https://llvm.org/D103056>`_,[range.all],Zoe Carver,✅
 `[range.iota] <http://wg21.link/range.iota>`_,iota_view,[range.all],Louis Dionne,Not started
-`[range.take] <http://wg21.link/range.take>`_,take_view,[range.all],Zoe Carver,In Progress
+`[range.take] <http://wg21.link/range.take>`_,take_view,[range.all],Zoe Carver,✅
 `[range.join] <http://wg21.link/range.join>`_,join_view,[range.all],Christopher Di Bella,Not started
 `[range.empty] <http://wg21.link/range.empty>`_,`empty_view <https://llvm.org/D103208>`_,[view.interface],Zoe Carver,✅
 `[range.single] <http://wg21.link/range.single>`_,single_view,[view.interface],Zoe Carver,In Progress

diff  --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 5fba7607756ef..7662a004de437 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -197,6 +197,7 @@ set(files
   __ranges/enable_view.h
   __ranges/non_propagating_cache.h
   __ranges/ref_view.h
+  __ranges/take_view.h
   __ranges/size.h
   __ranges/subrange.h
   __ranges/transform_view.h

diff  --git a/libcxx/include/__ranges/take_view.h b/libcxx/include/__ranges/take_view.h
new file mode 100644
index 0000000000000..deef79ebfb822
--- /dev/null
+++ b/libcxx/include/__ranges/take_view.h
@@ -0,0 +1,184 @@
+// -*- 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___RANGES_TAKE_VIEW_H
+#define _LIBCPP___RANGES_TAKE_VIEW_H
+
+#include <__algorithm/min.h>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/counted_iterator.h>
+#include <__iterator/default_sentinel.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__utility/move.h>
+#include <concepts>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<view _View>
+  class take_view : public view_interface<take_view<_View>> {
+    [[no_unique_address]] _View __base_ = _View();
+    range_
diff erence_t<_View> __count_ = 0;
+
+    template<bool> class __sentinel;
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    take_view() requires default_initializable<_View> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr take_view(_View __base, range_
diff erence_t<_View> __count)
+      : __base_(_VSTD::move(__base)), __count_(__count) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() && { return _VSTD::move(__base_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() requires (!__simple_view<_View>) {
+      if constexpr (sized_range<_View>) {
+        if constexpr (random_access_range<_View>) {
+          return ranges::begin(__base_);
+        } else {
+          using _DifferenceT = range_
diff erence_t<_View>;
+          auto __size = size();
+          return counted_iterator(ranges::begin(__base_), static_cast<_DifferenceT>(__size));
+        }
+      } else {
+        return counted_iterator(ranges::begin(__base_), __count_);
+      }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() const requires range<const _View> {
+      if constexpr (sized_range<const _View>) {
+        if constexpr (random_access_range<const _View>) {
+          return ranges::begin(__base_);
+        } else {
+          using _DifferenceT = range_
diff erence_t<const _View>;
+          auto __size = size();
+          return counted_iterator(ranges::begin(__base_), static_cast<_DifferenceT>(__size));
+        }
+      } else {
+        return counted_iterator(ranges::begin(__base_), __count_);
+      }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() requires (!__simple_view<_View>) {
+      if constexpr (sized_range<_View>) {
+        if constexpr (random_access_range<_View>) {
+          return ranges::begin(__base_) + size();
+        } else {
+          return default_sentinel;
+        }
+      } else {
+        return __sentinel<false>{ranges::end(__base_)};
+      }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() const requires range<const _View> {
+      if constexpr (sized_range<const _View>) {
+        if constexpr (random_access_range<const _View>) {
+          return ranges::begin(__base_) + size();
+        } else {
+          return default_sentinel;
+        }
+      } else {
+        return __sentinel<true>{ranges::end(__base_)};
+      }
+    }
+
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() requires sized_range<_View> {
+      auto __n = ranges::size(__base_);
+      // TODO: use ranges::min here.
+      return _VSTD::min(__n, static_cast<decltype(__n)>(__count_));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() const requires sized_range<const _View> {
+      auto __n = ranges::size(__base_);
+      // TODO: use ranges::min here.
+      return _VSTD::min(__n, static_cast<decltype(__n)>(__count_));
+    }
+  };
+
+  template<view _View>
+  template<bool _Const>
+  class take_view<_View>::__sentinel {
+    using _Base = __maybe_const<_Const, _View>;
+    template<bool _OtherConst>
+    using _Iter = counted_iterator<iterator_t<__maybe_const<_OtherConst, _View>>>;
+    [[no_unique_address]] sentinel_t<_Base> __end_ = sentinel_t<_Base>();
+
+    template<bool>
+    friend class take_view<_View>::__sentinel;
+
+public:
+    _LIBCPP_HIDE_FROM_ABI
+    __sentinel() = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit __sentinel(sentinel_t<_Base> __end) : __end_(_VSTD::move(__end)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __sentinel(__sentinel<!_Const> __s)
+      requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
+      : __end_(_VSTD::move(__s.__end_)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr sentinel_t<_Base> base() const { return __end_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr bool operator==(const _Iter<_Const>& __lhs, const __sentinel& __rhs) {
+      return __lhs.count() == 0 || __lhs.base() == __rhs.__end_;
+    }
+
+    template<bool _OtherConst = !_Const>
+      requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr bool operator==(const _Iter<_Const>& __lhs, const __sentinel& __rhs) {
+      return __lhs.count() == 0 || __lhs.base() == __rhs.__end_;
+    }
+  };
+
+  template<class _Range>
+  take_view(_Range&&, range_
diff erence_t<_Range>) -> take_view<views::all_t<_Range>>;
+
+  template<class _Tp>
+  inline constexpr bool enable_borrowed_range<take_view<_Tp>> = enable_borrowed_range<_Tp>;
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANGES_TAKE_VIEW_H

diff  --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index b5781b027f962..2054186bf940b 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -628,6 +628,7 @@ module std [system] {
       module ref_view               { private header "__ranges/ref_view.h"              }
       module size                   { private header "__ranges/size.h"                  }
       module subrange               { private header "__ranges/subrange.h"              }
+      module take_view              { private header "__ranges/take_view.h"             }
       module transform_view         { private header "__ranges/transform_view.h"        }
       module view_interface         { private header "__ranges/view_interface.h"        }
     }

diff  --git a/libcxx/include/ranges b/libcxx/include/ranges
index 47f66fd3f622c..0a78e0097bff7 100644
--- a/libcxx/include/ranges
+++ b/libcxx/include/ranges
@@ -156,6 +156,12 @@ namespace std::ranges {
 
   template<class T>
   inline constexpr bool enable_borrowed_range<common_view<T>> = enable_borrowed_range<T>;
+
+   // [range.take], take view
+  template<view> class take_view;
+
+  template<class T>
+  inline constexpr bool enable_borrowed_range<take_view<T>> = enable_borrowed_range<T>;
 }
 
 */
@@ -173,6 +179,7 @@ namespace std::ranges {
 #include <__ranges/enable_borrowed_range.h>
 #include <__ranges/enable_view.h>
 #include <__ranges/ref_view.h>
+#include <__ranges/take_view.h>
 #include <__ranges/size.h>
 #include <__ranges/subrange.h>
 #include <__ranges/transform_view.h>

diff  --git a/libcxx/test/libcxx/diagnostics/detail.headers/ranges/take_view.module.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/take_view.module.verify.cpp
new file mode 100644
index 0000000000000..39b1231cc3c9c
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/ranges/take_view.module.verify.cpp
@@ -0,0 +1,16 @@
+// -*- 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
+//
+//===----------------------------------------------------------------------===//
+
+// 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: '__ranges/take_view.h'}}
+#include <__ranges/take_view.h>

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/base.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/base.pass.cpp
new file mode 100644
index 0000000000000..392b943d08080
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/base.pass.cpp
@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// constexpr V base() const& requires copy_constructible<V>;
+// constexpr V base() &&;
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "types.h"
+
+constexpr bool hasLValueQualifiedBase(auto&& view) {
+    return requires { view.base(); };
+}
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  {
+    std::ranges::take_view<CopyableView> tv(CopyableView{buffer}, 0);
+    assert(tv.base().ptr_ == buffer);
+    assert(std::move(tv).base().ptr_ == buffer);
+
+    ASSERT_SAME_TYPE(decltype(tv.base()), CopyableView);
+    ASSERT_SAME_TYPE(decltype(std::move(tv).base()), CopyableView);
+    static_assert(hasLValueQualifiedBase(tv));
+  }
+
+  {
+    std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 1);
+    assert(std::move(tv).base().ptr_ == buffer);
+
+    ASSERT_SAME_TYPE(decltype(std::move(tv).base()), ContiguousView);
+    static_assert(!hasLValueQualifiedBase(tv));
+  }
+
+  {
+    const std::ranges::take_view<CopyableView> tv(CopyableView{buffer}, 2);
+    assert(tv.base().ptr_ == buffer);
+    assert(std::move(tv).base().ptr_ == buffer);
+
+    ASSERT_SAME_TYPE(decltype(tv.base()), CopyableView);
+    ASSERT_SAME_TYPE(decltype(std::move(tv).base()), CopyableView);
+    static_assert(hasLValueQualifiedBase(tv));
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/begin.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/begin.pass.cpp
new file mode 100644
index 0000000000000..e4c5f0d7fc48b
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/begin.pass.cpp
@@ -0,0 +1,75 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// constexpr auto begin() requires (!simple-view<V>);
+// constexpr auto begin() const requires range<const V>;
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "test_range.h"
+#include "types.h"
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  // sized_range && random_access_iterator
+  {
+    std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 4);
+    assert(tv.begin() == begin(SizedRandomAccessView(buffer)));
+    ASSERT_SAME_TYPE(decltype(tv.begin()), RandomAccessIter);
+  }
+
+  {
+    const std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 4);
+    assert(tv.begin() == begin(SizedRandomAccessView(buffer)));
+    ASSERT_SAME_TYPE(decltype(tv.begin()), RandomAccessIter);
+  }
+
+  // sized_range && !random_access_iterator
+  {
+    std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4);
+    assert(tv.begin() == std::counted_iterator<ForwardIter>(ForwardIter(buffer), 4));
+    ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<ForwardIter>);
+  }
+
+  {
+    const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4);
+    assert(tv.begin() == std::counted_iterator<ForwardIter>(ForwardIter(buffer), 4));
+    ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<ForwardIter>);
+  }
+
+  // !sized_range
+  {
+    std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+    assert(tv.begin() == std::counted_iterator<int*>(buffer, 4));
+    ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<int*>);
+  }
+
+  {
+    const std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+    assert(tv.begin() == std::counted_iterator<int*>(buffer, 4));
+    ASSERT_SAME_TYPE(decltype(tv.begin()), std::counted_iterator<int*>);
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/borrowing.compile.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/borrowing.compile.pass.cpp
new file mode 100644
index 0000000000000..bffaba055fdde
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/borrowing.compile.pass.cpp
@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// template<class T>
+//   inline constexpr bool enable_borrowed_range<take_view<T>> = enable_borrowed_range<T>;
+
+#include <ranges>
+#include <cassert>
+
+#include "test_iterators.h"
+
+struct View : std::ranges::view_base {
+  friend int* begin(View&);
+  friend int* begin(View const&);
+  friend sentinel_wrapper<int*> end(View&);
+  friend sentinel_wrapper<int*> end(View const&);
+};
+
+struct BorrowableView : std::ranges::view_base {
+  friend int* begin(BorrowableView&);
+  friend int* begin(BorrowableView const&);
+  friend sentinel_wrapper<int*> end(BorrowableView&);
+  friend sentinel_wrapper<int*> end(BorrowableView const&);
+};
+
+template<>
+inline constexpr bool std::ranges::enable_borrowed_range<BorrowableView> = true;
+
+static_assert(!std::ranges::enable_borrowed_range<std::ranges::take_view<View>>);
+static_assert( std::ranges::enable_borrowed_range<std::ranges::take_view<BorrowableView>>);

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/ctad.compile.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/ctad.compile.pass.cpp
new file mode 100644
index 0000000000000..2d0fd1947ee91
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/ctad.compile.pass.cpp
@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// template<class R>
+//   take_view(R&&, range_
diff erence_t<R>) -> take_view<views::all_t<R>>;
+
+#include <ranges>
+#include <cassert>
+#include <concepts>
+
+#include "test_iterators.h"
+
+struct View : std::ranges::view_base {
+  friend int* begin(View&);
+  friend int* begin(View const&);
+  friend sentinel_wrapper<int*> end(View&);
+  friend sentinel_wrapper<int*> end(View const&);
+};
+
+struct Range {
+  friend int* begin(Range&);
+  friend int* begin(Range const&);
+  friend sentinel_wrapper<int*> end(Range&);
+  friend sentinel_wrapper<int*> end(Range const&);
+};
+
+struct BorrowedRange {
+  friend int* begin(BorrowedRange&);
+  friend int* begin(BorrowedRange const&);
+  friend sentinel_wrapper<int*> end(BorrowedRange&);
+  friend sentinel_wrapper<int*> end(BorrowedRange const&);
+};
+
+template<>
+inline constexpr bool std::ranges::enable_borrowed_range<BorrowedRange> = true;
+
+void testCTAD() {
+    View v;
+    Range r;
+    BorrowedRange br;
+    static_assert(std::same_as<
+        decltype(std::ranges::take_view(v, 0)),
+        std::ranges::take_view<View>
+    >);
+    static_assert(std::same_as<
+        decltype(std::ranges::take_view(r, 0)),
+        std::ranges::take_view<std::ranges::ref_view<Range>>
+    >);
+    // std::ranges::take_view(std::move(r), 0) invalid. RValue range must be borrowed.
+    static_assert(std::same_as<
+        decltype(std::ranges::take_view(br, 0)),
+        std::ranges::take_view<std::ranges::ref_view<BorrowedRange>>
+    >);
+    static_assert(std::same_as<
+        decltype(std::ranges::take_view(std::move(br), 0)),
+        std::ranges::take_view<std::ranges::subrange<
+          int *, sentinel_wrapper<int *>, std::ranges::subrange_kind::unsized>>
+    >);
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/ctor.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/ctor.pass.cpp
new file mode 100644
index 0000000000000..ee42fd36522d4
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/ctor.pass.cpp
@@ -0,0 +1,83 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// take_view() requires default_initializable<V> = default;
+// constexpr take_view(V base, range_
diff erence_t<V> count);
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "test_range.h"
+#include "types.h"
+
+int globalBuffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+template<bool IsDefaultCtorable>
+struct DefaultConstructible : std::ranges::view_base {
+  DefaultConstructible() requires IsDefaultCtorable = default;
+  DefaultConstructible(int*);
+  int* begin();
+  sentinel_wrapper<int*> end();
+};
+
+struct SizedRandomAccessViewToGlobal : std::ranges::view_base {
+  RandomAccessIter begin() { return RandomAccessIter(globalBuffer); }
+  RandomAccessIter begin() const { return RandomAccessIter(globalBuffer); }
+  sentinel_wrapper<RandomAccessIter> end() {
+    return sentinel_wrapper<RandomAccessIter>{RandomAccessIter(globalBuffer + 8)};
+  }
+  sentinel_wrapper<RandomAccessIter> end() const {
+    return sentinel_wrapper<RandomAccessIter>{RandomAccessIter(globalBuffer + 8)};
+  }
+};
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  {
+    std::ranges::take_view<CopyableView> tv(CopyableView{buffer}, 0);
+    assert(tv.base().ptr_ == buffer);
+    assert(tv.begin() == tv.end()); // Checking we have correct size.
+  }
+
+  {
+    std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 1);
+    assert(std::move(tv).base().ptr_ == buffer);
+    assert(std::ranges::next(tv.begin(), 1) == tv.end()); // Checking we have correct size.
+  }
+
+  {
+    const std::ranges::take_view<CopyableView> tv(CopyableView{buffer}, 2);
+    assert(tv.base().ptr_ == buffer);
+    assert(std::ranges::next(tv.begin(), 2) == tv.end()); // Checking we have correct size.
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  // Tests for the default ctor.
+  static_assert( std::default_initializable<DefaultConstructible<true>>);
+  static_assert(!std::default_initializable<DefaultConstructible<false>>);
+
+  std::ranges::take_view<SizedRandomAccessViewToGlobal> tv;
+  assert(*tv.base().begin() == 1);
+  assert(tv.size() == 0);
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/end.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/end.pass.cpp
new file mode 100644
index 0000000000000..4ea7455eba0e7
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/end.pass.cpp
@@ -0,0 +1,83 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// constexpr auto end() requires (!simple-view<V>)
+// constexpr auto end() const requires range<const V>
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "test_range.h"
+#include "types.h"
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  // sized_range && random_access_iterator
+  {
+    std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 0);
+    assert(tv.end() == std::ranges::next(tv.begin(), 0));
+    ASSERT_SAME_TYPE(decltype(tv.end()), RandomAccessIter);
+  }
+
+  {
+    const std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 1);
+    assert(tv.end() == std::ranges::next(tv.begin(), 1));
+    ASSERT_SAME_TYPE(decltype(tv.end()), RandomAccessIter);
+  }
+
+  // sized_range && !random_access_iterator
+  {
+    std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 2);
+    assert(tv.end() == std::ranges::next(tv.begin(), 2));
+    ASSERT_SAME_TYPE(decltype(tv.end()), std::default_sentinel_t);
+  }
+
+  {
+    const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 3);
+    assert(tv.end() == std::ranges::next(tv.begin(), 3));
+    ASSERT_SAME_TYPE(decltype(tv.end()), std::default_sentinel_t);
+  }
+
+  // !sized_range
+  {
+    std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+    assert(tv.end() == std::ranges::next(tv.begin(), 4));
+
+    // The <sentinel> type.
+    static_assert(!std::same_as<decltype(tv.end()), std::default_sentinel_t>);
+    static_assert(!std::same_as<decltype(tv.end()), int*>);
+  }
+
+  {
+    const std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 5);
+    assert(tv.end() == std::ranges::next(tv.begin(), 5));
+  }
+
+  // Just to cover the case where count == 8.
+  {
+    std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 8);
+    assert(tv.end() == std::ranges::next(tv.begin(), 8));
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/range_concept_conformance.compile.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/range_concept_conformance.compile.pass.cpp
new file mode 100644
index 0000000000000..231349a4676d6
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/range_concept_conformance.compile.pass.cpp
@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// Range concept conformance tests for take_view.
+
+#include <ranges>
+#include <cassert>
+#include <concepts>
+
+#include "test_iterators.h"
+#include "test_range.h"
+
+static_assert(std::ranges::input_range<std::ranges::take_view<test_view<cpp20_input_iterator>>>);
+static_assert(std::ranges::forward_range<std::ranges::take_view<test_view<forward_iterator>>>);
+static_assert(std::ranges::bidirectional_range<std::ranges::take_view<test_view<bidirectional_iterator>>>);
+static_assert(std::ranges::random_access_range<std::ranges::take_view<test_view<random_access_iterator>>>);
+static_assert(std::ranges::contiguous_range<std::ranges::take_view<test_view<contiguous_iterator>>>);
+

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/base.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/base.pass.cpp
new file mode 100644
index 0000000000000..0d79e885db056
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/base.pass.cpp
@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// sentinel() = default;
+// constexpr explicit sentinel(sentinel_t<Base> end);
+// constexpr sentinel(sentinel<!Const> s)
+//   requires Const && convertible_to<sentinel_t<V>, sentinel_t<Base>>;
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "../types.h"
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+  auto sw = sentinel_wrapper<int *>(buffer + 8); // Note: not 4, but that's OK.
+
+  {
+    const std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+    assert(tv.end().base().base() == sw.base());
+    ASSERT_SAME_TYPE(decltype(tv.end().base()), sentinel_wrapper<int *>);
+  }
+
+  {
+    std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+    assert(tv.end().base().base() == sw.base());
+    ASSERT_SAME_TYPE(decltype(tv.end().base()), sentinel_wrapper<int *>);
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/ctor.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/ctor.pass.cpp
new file mode 100644
index 0000000000000..5c47d9ac59c54
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/ctor.pass.cpp
@@ -0,0 +1,62 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// sentinel() = default;
+// constexpr explicit sentinel(sentinel_t<Base> end);
+// constexpr sentinel(sentinel<!Const> s)
+//   requires Const && convertible_to<sentinel_t<V>, sentinel_t<Base>>;
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "../types.h"
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  {
+    // Test the default ctor.
+    std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+    assert(decltype(tv.end()){} == std::ranges::next(tv.begin(), 4));
+  }
+
+  {
+    std::ranges::take_view<ContiguousView> nonConst(ContiguousView{buffer}, 5);
+    const std::ranges::take_view<ContiguousView> tvConst(ContiguousView{buffer}, 5);
+    auto sent1 = nonConst.end();
+    // Convert to const. Note, we cannot go the other way.
+    std::remove_cv_t<decltype(tvConst.end())> sent2 = sent1;
+
+    assert(sent1 == std::ranges::next(tvConst.begin(), 5));
+    assert(sent2 == std::ranges::next(tvConst.begin(), 5));
+  }
+
+  {
+    std::ranges::take_view<CopyableView> tv(CopyableView{buffer}, 6);
+    auto sw = sentinel_wrapper<int *>(buffer + 6);
+    using Sent = decltype(tv.end());
+    Sent sent = Sent(sw);
+    assert(sent.base().base() == sw.base());
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/eq.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/eq.pass.cpp
new file mode 100644
index 0000000000000..93499f1e9d201
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/sentinel/eq.pass.cpp
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// sentinel() = default;
+// constexpr explicit sentinel(sentinel_t<Base> end);
+// constexpr sentinel(sentinel<!Const> s)
+//   requires Const && convertible_to<sentinel_t<V>, sentinel_t<Base>>;
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "../types.h"
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  {
+    {
+      const std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+      assert(tv.end() == std::ranges::next(tv.begin(), 4));
+      assert(std::ranges::next(tv.begin(), 4) == tv.end());
+    }
+
+    {
+      std::ranges::take_view<ContiguousView> tv(ContiguousView{buffer}, 4);
+      assert(tv.end() == std::ranges::next(tv.begin(), 4));
+      assert(std::ranges::next(tv.begin(), 4) == tv.end());
+    }
+  }
+
+  {
+    std::ranges::take_view<ContiguousView> tvNonConst(ContiguousView{buffer}, 4);
+    const std::ranges::take_view<ContiguousView> tvConst(ContiguousView{buffer}, 4);
+    assert(tvNonConst.end() == std::ranges::next(tvConst.begin(), 4));
+    assert(std::ranges::next(tvConst.begin(), 4) == tvNonConst.end());
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/size.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.take/size.pass.cpp
new file mode 100644
index 0000000000000..d589cf7288c5b
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/size.pass.cpp
@@ -0,0 +1,84 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// constexpr auto size() requires sized_range<V>
+// constexpr auto size() const requires sized_range<const V>
+
+#include <ranges>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "test_range.h"
+#include "types.h"
+
+template<class T>
+concept SizeEnabled = requires(const std::ranges::take_view<T>& tv) {
+  tv.size();
+};
+
+constexpr bool test() {
+  int buffer[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  {
+    static_assert( SizeEnabled<SizedRandomAccessView>);
+    static_assert(!SizeEnabled<CopyableView>);
+  }
+
+  {
+    std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 0);
+    assert(tv.size() == 0);
+  }
+
+  {
+    const std::ranges::take_view<SizedRandomAccessView> tv(SizedRandomAccessView{buffer}, 2);
+    assert(tv.size() == 2);
+  }
+
+  {
+    std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 4);
+    assert(tv.size() == 4);
+  }
+
+  {
+    const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 6);
+    assert(tv.size() == 6);
+  }
+
+  {
+    std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 8);
+    assert(tv.size() == 8);
+  }
+  {
+    const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 8);
+    assert(tv.size() == 8);
+  }
+
+  {
+    std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 10);
+    assert(tv.size() == 8);
+  }
+  {
+    const std::ranges::take_view<SizedForwardView> tv(SizedForwardView{buffer}, 10);
+    assert(tv.size() == 8);
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.take/types.h b/libcxx/test/std/ranges/range.adaptors/range.take/types.h
new file mode 100644
index 0000000000000..e260de2e38cf3
--- /dev/null
+++ b/libcxx/test/std/ranges/range.adaptors/range.take/types.h
@@ -0,0 +1,75 @@
+#ifndef TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_TAKE_TYPES_H
+#define TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_TAKE_TYPES_H
+
+#include <ranges>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+#include "test_range.h"
+
+struct ContiguousView : std::ranges::view_base {
+  int *ptr_;
+
+  constexpr ContiguousView(int* ptr) : ptr_(ptr) {}
+  ContiguousView(ContiguousView&&) = default;
+  ContiguousView& operator=(ContiguousView&&) = default;
+
+  constexpr int* begin() {return ptr_;}
+  constexpr int* begin() const {return ptr_;}
+  constexpr sentinel_wrapper<int*> end() {return sentinel_wrapper<int*>{ptr_ + 8};}
+  constexpr sentinel_wrapper<int*> end() const {return sentinel_wrapper<int*>{ptr_ + 8};}
+};
+
+struct CopyableView : std::ranges::view_base {
+  int *ptr_;
+  constexpr CopyableView(int* ptr) : ptr_(ptr) {}
+
+  constexpr int* begin() {return ptr_;}
+  constexpr int* begin() const {return ptr_;}
+  constexpr sentinel_wrapper<int*> end() {return sentinel_wrapper<int*>{ptr_ + 8};}
+  constexpr sentinel_wrapper<int*> end() const {return sentinel_wrapper<int*>{ptr_ + 8};}
+};
+
+using ForwardIter = forward_iterator<int*>;
+struct SizedForwardView : std::ranges::view_base {
+  int *ptr_;
+  constexpr SizedForwardView(int* ptr) : ptr_(ptr) {}
+  constexpr friend ForwardIter begin(SizedForwardView& view) { return ForwardIter(view.ptr_); }
+  constexpr friend ForwardIter begin(SizedForwardView const& view) { return ForwardIter(view.ptr_); }
+  constexpr friend sentinel_wrapper<ForwardIter> end(SizedForwardView& view) {
+    return sentinel_wrapper<ForwardIter>{ForwardIter(view.ptr_ + 8)};
+  }
+  constexpr friend sentinel_wrapper<ForwardIter> end(SizedForwardView const& view) {
+    return sentinel_wrapper<ForwardIter>{ForwardIter(view.ptr_ + 8)};
+  }
+};
+// Required to make SizedForwardView a sized view.
+constexpr auto operator-(sentinel_wrapper<ForwardIter> sent, ForwardIter iter) {
+  return sent.base().base() - iter.base();
+}
+constexpr auto operator-(ForwardIter iter, sentinel_wrapper<ForwardIter> sent) {
+  return iter.base() - sent.base().base();
+}
+
+using RandomAccessIter = random_access_iterator<int*>;
+struct SizedRandomAccessView : std::ranges::view_base {
+  int *ptr_;
+  constexpr SizedRandomAccessView(int* ptr) : ptr_(ptr) {}
+  constexpr friend RandomAccessIter begin(SizedRandomAccessView& view) { return RandomAccessIter(view.ptr_); }
+  constexpr friend RandomAccessIter begin(SizedRandomAccessView const& view) { return RandomAccessIter(view.ptr_); }
+  constexpr friend sentinel_wrapper<RandomAccessIter> end(SizedRandomAccessView& view) {
+    return sentinel_wrapper<RandomAccessIter>{RandomAccessIter(view.ptr_ + 8)};
+  }
+  constexpr friend sentinel_wrapper<RandomAccessIter> end(SizedRandomAccessView const& view) {
+    return sentinel_wrapper<RandomAccessIter>{RandomAccessIter(view.ptr_ + 8)};
+  }
+};
+// Required to make SizedRandomAccessView a sized view.
+constexpr auto operator-(sentinel_wrapper<RandomAccessIter> sent, RandomAccessIter iter) {
+  return sent.base().base() - iter.base();
+}
+constexpr auto operator-(RandomAccessIter iter, sentinel_wrapper<RandomAccessIter> sent) {
+  return iter.base() - sent.base().base();
+}
+
+#endif // TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_TAKE_TYPES_H

diff  --git a/libcxx/test/std/ranges/range.adaptors/range.transform/ctad.compile.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.transform/ctad.compile.pass.cpp
index d19eeb53cfffe..bbd4843afdfe5 100644
--- a/libcxx/test/std/ranges/range.adaptors/range.transform/ctad.compile.pass.cpp
+++ b/libcxx/test/std/ranges/range.adaptors/range.transform/ctad.compile.pass.cpp
@@ -14,6 +14,7 @@
 // CTAD tests.
 
 #include <ranges>
+#include <concepts>
 
 #include "test_macros.h"
 #include "types.h"

diff  --git a/libcxx/test/support/test_range.h b/libcxx/test/support/test_range.h
index 9ded1325c7ce4..c99e3f72e8bf9 100644
--- a/libcxx/test/support/test_range.h
+++ b/libcxx/test/support/test_range.h
@@ -21,7 +21,6 @@ struct sentinel {
   bool operator==(std::input_or_output_iterator auto const&) const;
 };
 
-// clang-format off
 template <template <class...> class I>
 requires std::input_or_output_iterator<I<int*> >
 struct test_range {
@@ -54,6 +53,13 @@ struct test_non_const_common_range {
   I<int*> end();
 };
 
-// clang-format on
+template <template <class...> class I>
+requires std::input_or_output_iterator<I<int*> >
+struct test_view : std::ranges::view_base {
+  I<int*> begin();
+  I<int const*> begin() const;
+  sentinel end();
+  sentinel end() const;
+};
 
 #endif // LIBCXX_TEST_SUPPORT_TEST_RANGE_H


        


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