[libc++][ranges] LWG3618: Unnecessary iter_move for transform_view::iterator
#91809
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@llvm/pr-subscribers-libcxx Author: Xiaoyang Liu (xiaoyang-sde) ChangesIntroductionThis patch implements LWG3618: Unnecessary
ReferenceFull diff: https://github.com/llvm/llvm-project/pull/91809.diff 2 Files Affected:
diff --git a/libcxx/docs/Status/Cxx23Issues.csv b/libcxx/docs/Status/Cxx23Issues.csv
index 04f6e23375acd..55db4d209a407 100644
--- a/libcxx/docs/Status/Cxx23Issues.csv
+++ b/libcxx/docs/Status/Cxx23Issues.csv
@@ -146,7 +146,7 @@
"`3610 <https://wg21.link/LWG3610>`__","``iota_view::size`` sometimes rejects integer-class types","February 2022","","","|ranges|"
"`3612 <https://wg21.link/LWG3612>`__","Inconsistent pointer alignment in ``std::format`` ","February 2022","|Complete|","14.0","|format|"
"`3616 <https://wg21.link/LWG3616>`__","LWG 3498 seems to miss the non-member ``swap`` for ``basic_syncbuf`` ","February 2022","",""
-"`3618 <https://wg21.link/LWG3618>`__","Unnecessary ``iter_move`` for ``transform_view::iterator`` ","February 2022","","","|ranges|"
+"`3618 <https://wg21.link/LWG3618>`__","Unnecessary ``iter_move`` for ``transform_view::iterator`` ","February 2022","|Complete|","19.0","|ranges|"
"`3619 <https://wg21.link/LWG3619>`__","Specification of ``vformat_to`` contains ill-formed ``formatted_size`` calls","February 2022","|Nothing to do|","","|format|"
"`3621 <https://wg21.link/LWG3621>`__","Remove feature-test macro ``__cpp_lib_monadic_optional`` ","February 2022","|Complete|","15.0"
"`3632 <https://wg21.link/LWG3632>`__","``unique_ptr`` ""Mandates: This constructor is not selected by class template argument deduction""","February 2022","|Nothing to do|",""
diff --git a/libcxx/include/__ranges/transform_view.h b/libcxx/include/__ranges/transform_view.h
index dc3aaa59ed8c3..bcce389c0e680 100644
--- a/libcxx/include/__ranges/transform_view.h
+++ b/libcxx/include/__ranges/transform_view.h
@@ -326,13 +326,6 @@ class transform_view<_View, _Fn>::__iterator : public __transform_view_iterator_
{
return __x.__current_ - __y.__current_;
}
-
- _LIBCPP_HIDE_FROM_ABI friend constexpr decltype(auto) iter_move(const __iterator& __i) noexcept(noexcept(*__i)) {
- if constexpr (is_lvalue_reference_v<decltype(*__i)>)
- return std::move(*__i);
- else
- return *__i;
- }
};
# if _LIBCPP_STD_VER >= 23
|
mordante
reviewed
May 16, 2024
| @@ -146,7 +146,7 @@ | |||
| "`3610 <https://wg21.link/LWG3610>`__","``iota_view::size`` sometimes rejects integer-class types","February 2022","","","|ranges|" | |||
| "`3612 <https://wg21.link/LWG3612>`__","Inconsistent pointer alignment in ``std::format`` ","February 2022","|Complete|","14.0","|format|" | |||
| "`3616 <https://wg21.link/LWG3616>`__","LWG 3498 seems to miss the non-member ``swap`` for ``basic_syncbuf`` ","February 2022","","" | |||
| "`3618 <https://wg21.link/LWG3618>`__","Unnecessary ``iter_move`` for ``transform_view::iterator`` ","February 2022","","","|ranges|" | |||
| "`3618 <https://wg21.link/LWG3618>`__","Unnecessary ``iter_move`` for ``transform_view::iterator`` ","February 2022","|Complete|","19.0","|ranges|" | |||
There was a problem hiding this comment.
The LWG-issues adds a noexcept. This is not tested in libcxx/test/std/ranges/range.adaptors/range.transform/iterator/deref.pass.cpp. Please update this test.
ldionne
requested changes
Jul 4, 2024
added 2 commits
July 4, 2024 22:03
xiaoyang-sde
commented
Jul 5, 2024
| @@ -37,7 +37,7 @@ int main(int, char**) { | |||
| using View = std::ranges::transform_view<MoveOnlyView, PlusOneNoexcept>; | |||
| View transformView(MoveOnlyView{buff}, PlusOneNoexcept{}); | |||
| assert(*transformView.begin() == 1); | |||
| LIBCPP_ASSERT_NOEXCEPT(*std::declval<std::ranges::iterator_t<View>>()); | |||
| ASSERT_NOEXCEPT(*std::declval<std::ranges::iterator_t<View>>()); | |||
There was a problem hiding this comment.
The operator* previously provided a noexcept specifier as a libc++ extension. Following the adoption of this LWG issue, the noexcept specifier is now standard behavior.
ldionne
approved these changes
Jul 16, 2024
Could you please merge this patch? Thank you! |
yuxuanchen1997
pushed a commit
that referenced
this pull request
Jul 25, 2024
…::iterator` (#91809) Summary: ## Introduction This patch implements LWG3618: Unnecessary `iter_move` for `transform_view::iterator`. `transform_view`'s iterator currently specifies a customization point for `iter_move`. This customization point does the same thing that the default implementation would do, but its sole purpose is to ensure the appropriate conditional `noexcept` specification. ## Reference - [[range.transform.iterator]](https://eel.is/c++draft/range.transform.iterator) - [LWG3618](https://cplusplus.github.io/LWG/issue3618) Test Plan: Reviewers: Subscribers: Tasks: Tags: Differential Revision: https://phabricator.intern.facebook.com/D60251361
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Introduction
This patch implements LWG3618: Unnecessary
iter_movefortransform_view::iterator.transform_view's iterator currently specifies a customization point foriter_move. This customization point does the same thing that the default implementation would do, but its sole purpose is to ensure the appropriate conditionalnoexceptspecification.Reference