[libcxx-commits] [libcxx] [libc++][ranges] Mark LWG3664 as resolved (PR #210550)
Lucas Mellone via libcxx-commits
libcxx-commits at lists.llvm.org
Sat Jul 18 14:58:47 PDT 2026
https://github.com/lknknm updated https://github.com/llvm/llvm-project/pull/210550
>From 23293789342393617472800afc72656011d5334f Mon Sep 17 00:00:00 2001
From: Lucas Mellone <github.snugness349 at passinbox.com>
Date: Sat, 18 Jul 2026 23:13:24 +0200
Subject: [PATCH 1/3] apply: changes from proposal and mark as Complete
---
libcxx/docs/Status/Cxx23Issues.csv | 2 +-
libcxx/include/__iterator/distance.h | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/libcxx/docs/Status/Cxx23Issues.csv b/libcxx/docs/Status/Cxx23Issues.csv
index 91c4dc462c0c9..0e13c6dc62bfe 100644
--- a/libcxx/docs/Status/Cxx23Issues.csv
+++ b/libcxx/docs/Status/Cxx23Issues.csv
@@ -249,7 +249,7 @@
"`LWG2295 <https://wg21.link/LWG2295>`__","Locale name when the provided ``Facet`` is a ``nullptr``","2023-02 (Issaquah)","","","`#105063 <https://github.com/llvm/llvm-project/issues/105063>`__",""
"`LWG3032 <https://wg21.link/LWG3032>`__","``ValueSwappable`` requirement missing for ``push_heap`` and ``make_heap``","2023-02 (Issaquah)","","","`#105064 <https://github.com/llvm/llvm-project/issues/105064>`__",""
"`LWG3085 <https://wg21.link/LWG3085>`__","``char_traits::copy`` precondition too weak","2023-02 (Issaquah)","","","`#105065 <https://github.com/llvm/llvm-project/issues/105065>`__",""
-"`LWG3664 <https://wg21.link/LWG3664>`__","`LWG 3392 <https://wg21.link/LWG3392>`__ ``broke std::ranges::distance(a, a+3)``","2023-02 (Issaquah)","","","`#105066 <https://github.com/llvm/llvm-project/issues/105066>`__",""
+"`LWG3664 <https://wg21.link/LWG3664>`__","`LWG 3392 <https://wg21.link/LWG3392>`__ ``broke std::ranges::distance(a, a+3)``","2023-02 (Issaquah)","|Complete|","","`#105066 <https://github.com/llvm/llvm-project/issues/105066>`__",""
"`LWG3720 <https://wg21.link/LWG3720>`__","Restrict the valid types of ``arg-id`` for width and precision in ``std-format-spec``","2023-02 (Issaquah)","|Complete|","17","`#105067 <https://github.com/llvm/llvm-project/issues/105067>`__",""
"`LWG3756 <https://wg21.link/LWG3756>`__","Is the ``std::atomic_flag`` class signal-safe?","2023-02 (Issaquah)","","","`#105068 <https://github.com/llvm/llvm-project/issues/105068>`__",""
"`LWG3769 <https://wg21.link/LWG3769>`__","``basic_const_iterator::operator==`` causes infinite constraint recursion","2023-02 (Issaquah)","","","`#105069 <https://github.com/llvm/llvm-project/issues/105069>`__",""
diff --git a/libcxx/include/__iterator/distance.h b/libcxx/include/__iterator/distance.h
index c7c4ff22d6e9f..bbdd30e56730f 100644
--- a/libcxx/include/__iterator/distance.h
+++ b/libcxx/include/__iterator/distance.h
@@ -86,11 +86,11 @@ struct __distance {
}
template <class _Ip, sized_sentinel_for<decay_t<_Ip>> _Sp>
- [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Ip> operator()(_Ip&& __first, _Sp __last) const {
+ [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<decay_t<_Ip>> operator()(_Ip&& __first, _Sp __last) const {
if constexpr (sized_sentinel_for<_Sp, __remove_cvref_t<_Ip>>) {
return __last - __first;
} else {
- return __last - decay_t<_Ip>(__first);
+ return __last - static_cast<decay_t<_Ip>>(__first);
}
}
>From cbed72094e96ce8a7756aa588be4dc25f608635b Mon Sep 17 00:00:00 2001
From: Lucas Mellone <github.snugness349 at passinbox.com>
Date: Sat, 18 Jul 2026 23:33:56 +0200
Subject: [PATCH 2/3] clang-format
---
libcxx/include/__iterator/distance.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/libcxx/include/__iterator/distance.h b/libcxx/include/__iterator/distance.h
index bbdd30e56730f..e0a2590253c71 100644
--- a/libcxx/include/__iterator/distance.h
+++ b/libcxx/include/__iterator/distance.h
@@ -86,7 +86,8 @@ struct __distance {
}
template <class _Ip, sized_sentinel_for<decay_t<_Ip>> _Sp>
- [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<decay_t<_Ip>> operator()(_Ip&& __first, _Sp __last) const {
+ [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<decay_t<_Ip>>
+ operator()(_Ip&& __first, _Sp __last) const {
if constexpr (sized_sentinel_for<_Sp, __remove_cvref_t<_Ip>>) {
return __last - __first;
} else {
>From a265367976e6651929998984e3284210eab11585 Mon Sep 17 00:00:00 2001
From: Lucas Mellone <github.snugness349 at passinbox.com>
Date: Sat, 18 Jul 2026 23:58:32 +0200
Subject: [PATCH 3/3] update: comments in tests
---
.../range.iter.ops.distance/iterator_sentinel.pass.cpp | 2 +-
.../range.iter.ops/range.iter.ops.distance/lwg3664.pass.cpp | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/iterator_sentinel.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/iterator_sentinel.pass.cpp
index c34d59e405a9e..1888f606465b2 100644
--- a/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/iterator_sentinel.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/iterator_sentinel.pass.cpp
@@ -13,7 +13,7 @@
// constexpr iter_difference_t<I> ranges::distance(I first, S last);
//
// template<class I, sized_sentinel_for<decay_t<I>> S>
-// constexpr iter_difference_t<I> ranges::distance(I&& first, S last); // TODO: update when LWG3664 is resolved
+// constexpr iter_difference_t<decay_t<I>> ranges::distance(I&& first, S last);
#include <array>
#include <cassert>
diff --git a/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/lwg3664.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/lwg3664.pass.cpp
index 164101c2bf5a8..bac0ffba1e7f1 100644
--- a/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/lwg3664.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/range.iter.ops/range.iter.ops.distance/lwg3664.pass.cpp
@@ -13,7 +13,7 @@
// constexpr iter_difference_t<I> ranges::distance(I first, S last);
//
// template<class I, sized_sentinel_for<decay_t<I>> S>
-// constexpr iter_difference_t<I> ranges::distance(const I& first, S last);
+// constexpr iter_difference_t<decay_t<I>> ranges::distance(I&& first, S last);
#include <cassert>
#include <iterator>
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