[libc++] Partly addresses LWG3798.

  LWG3798 Rvalue reference and iterator_category

The changes are only applied to `ranges::transform_view`, the other
views haven't been implemented yet.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D142815

diff --git a/libcxx/docs/Status/Cxx2b.rst b/libcxx/docs/Status/Cxx2b.rst
index e79ed28..b50792a 100644 (file)
--- a/libcxx/docs/Status/Cxx2b.rst
+++ b/libcxx/docs/Status/Cxx2b.rst
@@ -52,3 +52,7 @@ Library Working Group Issues Status
    :file: Cxx2bIssues.csv
    :header-rows: 1
    :widths: auto
+
+.. note::
+
+   .. [#note-LWG3798] LWG3798: ``join_with_view``, ``zip_transform_view``, and ``adjacent_transform_view`` haven't been done yet since these types aren't implemented yet.

diff --git a/libcxx/docs/Status/Cxx2bIssues.csv b/libcxx/docs/Status/Cxx2bIssues.csv
index 0dd84d7..b286ad3 100644 (file)
--- a/libcxx/docs/Status/Cxx2bIssues.csv
+++ b/libcxx/docs/Status/Cxx2bIssues.csv
@@ -234,7 +234,7 @@
 "`3792 <https://wg21.link/LWG3792>`__","``__cpp_lib_constexpr_algorithms`` should also be defined in ``<utility>``", "November 2022","|Complete|","16.0",""
 "`3795 <https://wg21.link/LWG3795>`__","Self-move-assignment of ``std::future`` and ``std::shared_future`` have unimplementable postconditions", "November 2022","","",""
 "`3796 <https://wg21.link/LWG3796>`__","``movable-box`` as member should use ``default-initialization`` instead of ``copy-initialization``", "November 2022","","","|ranges|"
-"`3798 <https://wg21.link/LWG3798>`__","Rvalue reference and ``iterator_category``", "November 2022","","",""
+"`3798 <https://wg21.link/LWG3798>`__","Rvalue reference and ``iterator_category``", "November 2022","|Partial| [#note-LWG3798]_","","|ranges|"
 "`3801 <https://wg21.link/LWG3801>`__","``cartesian_product_view::iterator::distance-from`` ignores the size of last underlying range", "November 2022","","","|ranges|"
 "`3814 <https://wg21.link/LWG3814>`__","Add freestanding items requested by NB comments", "November 2022","","",""
 "`3816 <https://wg21.link/LWG3816>`__","``flat_map`` and ``flat_multimap`` should impose sequence container requirements", "November 2022","","","|flat_containers|"

diff --git a/libcxx/include/__iterator/iterator_traits.h b/libcxx/include/__iterator/iterator_traits.h
index c9d8944..c67d459 100644 (file)
--- a/libcxx/include/__iterator/iterator_traits.h
+++ b/libcxx/include/__iterator/iterator_traits.h
@@ -190,7 +190,7 @@ template<class _Ip>
 concept __cpp17_forward_iterator =
   __cpp17_input_iterator<_Ip> &&
   constructible_from<_Ip> &&
-  is_lvalue_reference_v<iter_reference_t<_Ip>> &&
+  is_reference_v<iter_reference_t<_Ip>> &&
   same_as<remove_cvref_t<iter_reference_t<_Ip>>,
           typename indirectly_readable_traits<_Ip>::value_type> &&
   requires(_Ip __i) {

diff --git a/libcxx/include/__ranges/transform_view.h b/libcxx/include/__ranges/transform_view.h
index 66d9e80..ebdff77 100644 (file)
--- a/libcxx/include/__ranges/transform_view.h
+++ b/libcxx/include/__ranges/transform_view.h
@@ -166,7 +166,7 @@ struct __transform_view_iterator_category_base<_View, _Fn> {
   using _Cat = typename iterator_traits<iterator_t<_View>>::iterator_category;
 
   using iterator_category = conditional_t<
-    is_lvalue_reference_v<invoke_result_t<_Fn&, range_reference_t<_View>>>,
+    is_reference_v<invoke_result_t<_Fn&, range_reference_t<_View>>>,
     conditional_t<
       derived_from<_Cat, contiguous_iterator_tag>,
       random_access_iterator_tag,

diff --git a/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_bidirectional_iterator.compile.pass.cpp b/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_bidirectional_iterator.compile.pass.cpp
index 7ba8c75..0b8dd9f 100644 (file)
--- a/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_bidirectional_iterator.compile.pass.cpp
+++ b/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_bidirectional_iterator.compile.pass.cpp
@@ -72,7 +72,7 @@ static_assert(!std::__iterator_traits_detail::__cpp17_bidirectional_iterator<std
 static_assert(!std::__iterator_traits_detail::__cpp17_bidirectional_iterator<std::back_insert_iterator<std::vector<int>>>);
 static_assert(!std::__iterator_traits_detail::__cpp17_bidirectional_iterator<std::front_insert_iterator<std::vector<int>>>);
 static_assert(!std::__iterator_traits_detail::__cpp17_bidirectional_iterator<std::insert_iterator<std::vector<int>>>);
-static_assert(!std::__iterator_traits_detail::__cpp17_bidirectional_iterator<std::move_iterator<int*>>);
+static_assert(std::__iterator_traits_detail::__cpp17_bidirectional_iterator<std::move_iterator<int*>>);
 
 // <list>
 static_assert(std::__iterator_traits_detail::__cpp17_bidirectional_iterator<std::list<int>::iterator>);

diff --git a/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_forward_iterator.compile.pass.cpp b/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_forward_iterator.compile.pass.cpp
index 7a2000a..b92b572 100644 (file)
--- a/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_forward_iterator.compile.pass.cpp
+++ b/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_forward_iterator.compile.pass.cpp
@@ -72,7 +72,7 @@ static_assert(std::__iterator_traits_detail::__cpp17_forward_iterator<std::forwa
 static_assert(!std::__iterator_traits_detail::__cpp17_forward_iterator<std::back_insert_iterator<std::vector<int>>>);
 static_assert(!std::__iterator_traits_detail::__cpp17_forward_iterator<std::front_insert_iterator<std::vector<int>>>);
 static_assert(!std::__iterator_traits_detail::__cpp17_forward_iterator<std::insert_iterator<std::vector<int>>>);
-static_assert(!std::__iterator_traits_detail::__cpp17_forward_iterator<std::move_iterator<int*>>);
+static_assert(std::__iterator_traits_detail::__cpp17_forward_iterator<std::move_iterator<int*>>);
 
 // <list>
 static_assert(std::__iterator_traits_detail::__cpp17_forward_iterator<std::list<int>::iterator>);

diff --git a/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_random_access_iterator.compile.pass.cpp b/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_random_access_iterator.compile.pass.cpp
index ddbf60f..f4adb6a 100644 (file)
--- a/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_random_access_iterator.compile.pass.cpp
+++ b/libcxx/test/libcxx/iterators/iterator.requirements/iterator.assoc.types/iterator.traits/legacy_random_access_iterator.compile.pass.cpp
@@ -72,7 +72,7 @@ static_assert(!std::__iterator_traits_detail::__cpp17_random_access_iterator<std
 static_assert(!std::__iterator_traits_detail::__cpp17_random_access_iterator<std::back_insert_iterator<std::vector<int>>>);
 static_assert(!std::__iterator_traits_detail::__cpp17_random_access_iterator<std::front_insert_iterator<std::vector<int>>>);
 static_assert(!std::__iterator_traits_detail::__cpp17_random_access_iterator<std::insert_iterator<std::vector<int>>>);
-static_assert(!std::__iterator_traits_detail::__cpp17_random_access_iterator<std::move_iterator<int*>>);
+static_assert(std::__iterator_traits_detail::__cpp17_random_access_iterator<std::move_iterator<int*>>);
 
 // <list>
 static_assert(!std::__iterator_traits_detail::__cpp17_random_access_iterator<std::list<int>::iterator>);

diff --git a/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/types.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/types.pass.cpp
index 2c095d8..25d8936 100644 (file)
--- a/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/types.pass.cpp
+++ b/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/types.pass.cpp
@@ -44,6 +44,15 @@ constexpr bool test() {
     static_assert(std::same_as<typename TIter::difference_type, std::ptrdiff_t>);
   }
   {
+    // Member typedefs for random access iterator, LWG3798 rvalue reference.
+    using TView = std::ranges::transform_view<RandomAccessView, IncrementRvalueRef>;
+    using TIter = std::ranges::iterator_t<TView>;
+    static_assert(std::same_as<typename TIter::iterator_concept, std::random_access_iterator_tag>);
+    static_assert(std::same_as<typename TIter::iterator_category, std::random_access_iterator_tag>);
+    static_assert(std::same_as<typename TIter::value_type, int>);
+    static_assert(std::same_as<typename TIter::difference_type, std::ptrdiff_t>);
+  }
+  {
     // Member typedefs for random access iterator/not-lvalue-ref.
     using TView = std::ranges::transform_view<RandomAccessView, PlusOneMutable>;
     using TIter = std::ranges::iterator_t<TView>;