[libcxx-commits] [libcxx] [libc++][ranges] LWG3618: Unnecessary `iter_move` for `transform_view::iterator` (PR #91809)

[Xiaoyang Liu via libcxx-commits]

https://github.com/xiaoyang-sde updated https://github.com/llvm/llvm-project/pull/91809

>From 007abaa968e7467c7a1c25120e9d6d5818936805 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Fri, 10 May 2024 16:56:12 -0400
Subject: [PATCH 1/2] [libc++][ranges] LWG3618: Unnecessary 'iter_move' for
 'transform_view::iterator'

---
 libcxx/docs/Status/Cxx23Issues.csv       | 2 +-
 libcxx/include/__ranges/transform_view.h | 7 -------
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/libcxx/docs/Status/Cxx23Issues.csv b/libcxx/docs/Status/Cxx23Issues.csv
index cc601b3cd3c96f..8fe8ab89e88a5a 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 dc3aaa59ed8c3f..bcce389c0e6809 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

>From 18ab45fb9c3e9b799d796c8e820cad2baad4594e Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Thu, 4 Jul 2024 22:13:45 -0700
Subject: [PATCH 2/2] [libc++][ranges] LWG3618: Unnecessary 'iter_move' for
 'transform_view::iterator'

---
 .../range.transform/iterator/deref.pass.cpp   |  2 +-
 .../iterator/iter_move.pass.cpp               | 49 -------------------
 2 files changed, 1 insertion(+), 50 deletions(-)
 delete mode 100644 libcxx/test/std/ranges/range.adaptors/range.transform/iterator/iter_move.pass.cpp

diff --git a/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/deref.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/deref.pass.cpp
index 06eb91dba22ff3..5d8bf51c696960 100644
--- a/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/deref.pass.cpp
+++ b/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/deref.pass.cpp
@@ -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>>());
     ASSERT_SAME_TYPE(int, decltype(*std::declval<View>().begin()));
   }
   {
diff --git a/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/iter_move.pass.cpp b/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/iter_move.pass.cpp
deleted file mode 100644
index ea1e4b61412c47..00000000000000
--- a/libcxx/test/std/ranges/range.adaptors/range.transform/iterator/iter_move.pass.cpp
+++ /dev/null
@@ -1,49 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-
-// friend constexpr decltype(auto) iter_move(const iterator& i)
-//    noexcept(noexcept(invoke(i.parent_->fun_, *i.current_)))
-
-#include <ranges>
-
-#include "test_macros.h"
-#include "../types.h"
-
-constexpr bool test() {
-  int buff[8] = {0, 1, 2, 3, 4, 5, 6, 7};
-
-  {
-    std::ranges::transform_view transformView(MoveOnlyView{buff}, PlusOneMutable{});
-    auto iter = transformView.begin();
-    ASSERT_NOT_NOEXCEPT(std::ranges::iter_move(iter));
-
-    assert(std::ranges::iter_move(iter) == 1);
-    assert(std::ranges::iter_move(iter + 2) == 3);
-
-    ASSERT_SAME_TYPE(int, decltype(std::ranges::iter_move(iter)));
-    ASSERT_SAME_TYPE(int, decltype(std::ranges::iter_move(std::move(iter))));
-  }
-
-  {
-    LIBCPP_ASSERT_NOEXCEPT(std::ranges::iter_move(
-      std::declval<std::ranges::iterator_t<std::ranges::transform_view<MoveOnlyView, PlusOneNoexcept>>&>()));
-    ASSERT_NOT_NOEXCEPT(std::ranges::iter_move(
-      std::declval<std::ranges::iterator_t<std::ranges::transform_view<MoveOnlyView, PlusOneMutable>>&>()));
-  }
-
-  return true;
-}
-
-int main(int, char**) {
-  test();
-  static_assert(test());
-
-  return 0;
-}