[libcxx-commits] [libcxx] [libc++][ranges] Ensure range access CPOs are provided in `<iterator>` (PR #151745)
A. Jiang via libcxx-commits
libcxx-commits at lists.llvm.org
Tue Aug 5 02:23:00 PDT 2025
https://github.com/frederick-vs-ja updated https://github.com/llvm/llvm-project/pull/151745
>From d73c62f02fc82a4504bcd71acfcb1c7b67fd6132 Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34 at live.cn>
Date: Sat, 2 Aug 2025 02:22:12 +0800
Subject: [PATCH 1/2] [libc++][ranges] Ensure range access CPOs are provided in
`<iterator>`
Per [range.access.general]/1, these CPOs are also provided in
`<iterator>`. Currently only some of them are provided via transitive
inclusion when only `<iterator>` is included.
Drive-by: Add an entry for `ranges::reserve_hint` in the general test
file for CPOs.
---
libcxx/include/iterator | 10 ++++
libcxx/include/ranges | 8 +--
.../cpo.compile.pass.cpp | 4 ++
.../include.iterator.compile.pass.cpp | 60 +++++++++++++++++++
4 files changed, 75 insertions(+), 7 deletions(-)
create mode 100644 libcxx/test/std/ranges/range.access/include.iterator.compile.pass.cpp
diff --git a/libcxx/include/iterator b/libcxx/include/iterator
index d25fdfd2a8b33..fc8bdc5e6bcf6 100644
--- a/libcxx/include/iterator
+++ b/libcxx/include/iterator
@@ -737,6 +737,16 @@ template <class E> constexpr const E* data(initializer_list<E> il) noexcept;
# include <compare>
# include <concepts>
+// [range.access.general]
+# if _LIBCPP_STD_VER >= 20
+# include <__ranges/access.h>
+# include <__ranges/data.h>
+# include <__ranges/empty.h>
+# include <__ranges/rbegin.h>
+# include <__ranges/rend.h>
+# include <__ranges/size.h>
+# endif
+
# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
# endif
diff --git a/libcxx/include/ranges b/libcxx/include/ranges
index 96d7a6b897188..b86dd78ecb255 100644
--- a/libcxx/include/ranges
+++ b/libcxx/include/ranges
@@ -405,17 +405,14 @@ namespace std {
# include <__config>
# if _LIBCPP_STD_VER >= 20
-# include <__ranges/access.h>
# include <__ranges/all.h>
# include <__ranges/common_view.h>
# include <__ranges/concepts.h>
# include <__ranges/counted.h>
# include <__ranges/dangling.h>
-# include <__ranges/data.h>
# include <__ranges/drop_view.h>
# include <__ranges/drop_while_view.h>
# include <__ranges/elements_view.h>
-# include <__ranges/empty.h>
# include <__ranges/empty_view.h>
# include <__ranges/enable_borrowed_range.h>
# include <__ranges/enable_view.h>
@@ -423,12 +420,9 @@ namespace std {
# include <__ranges/iota_view.h>
# include <__ranges/join_view.h>
# include <__ranges/lazy_split_view.h>
-# include <__ranges/rbegin.h>
# include <__ranges/ref_view.h>
-# include <__ranges/rend.h>
# include <__ranges/reverse_view.h>
# include <__ranges/single_view.h>
-# include <__ranges/size.h>
# include <__ranges/split_view.h>
# include <__ranges/subrange.h>
# include <__ranges/take_view.h>
@@ -460,7 +454,7 @@ namespace std {
// [ranges.syn]
# include <compare>
# include <initializer_list>
-# include <iterator>
+# include <iterator> // some CPOs are provided in <iterator> per [range.access.general]
// [tuple.helper]
# include <__tuple/tuple_element.h>
diff --git a/libcxx/test/std/library/description/conventions/customization.point.object/cpo.compile.pass.cpp b/libcxx/test/std/library/description/conventions/customization.point.object/cpo.compile.pass.cpp
index 678483b9b2f2f..49497875dcf95 100644
--- a/libcxx/test/std/library/description/conventions/customization.point.object/cpo.compile.pass.cpp
+++ b/libcxx/test/std/library/description/conventions/customization.point.object/cpo.compile.pass.cpp
@@ -81,6 +81,10 @@ static_assert(test(std::ranges::rend, a));
static_assert(test(std::ranges::size, a));
static_assert(test(std::ranges::ssize, a));
+#if TEST_STD_VER >= 26
+// static_assert(test(std::views::reserve_hint, a));
+#endif
+
// [range.factories]
// views::empty<T> is not a CPO
static_assert(test(std::views::iota, 1));
diff --git a/libcxx/test/std/ranges/range.access/include.iterator.compile.pass.cpp b/libcxx/test/std/ranges/range.access/include.iterator.compile.pass.cpp
new file mode 100644
index 0000000000000..a3c59166eeab0
--- /dev/null
+++ b/libcxx/test/std/ranges/range.access/include.iterator.compile.pass.cpp
@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// 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: std-at-least-c++20
+
+// [range.access.general]/1:
+// In addition to being available via inclusion of the <ranges> header, the customization point objects in
+// [range.access] are available when the header <iterator> is included.
+
+#include <iterator>
+#include <type_traits>
+
+#include "test_macros.h"
+
+template <class CPO, class... Args>
+constexpr bool test(CPO& o, Args&&...) {
+ static_assert(std::is_const_v<CPO>);
+ static_assert(std::is_class_v<CPO>);
+ static_assert(std::is_trivially_copyable_v<CPO>);
+ static_assert(std::is_trivially_default_constructible_v<CPO>);
+
+ auto p = o;
+ using T = decltype(p);
+
+ // The type of a customization point object, ignoring cv-qualifiers, shall model semiregular.
+ static_assert(std::semiregular<T>);
+
+ // The type T of a customization point object, ignoring cv-qualifiers, shall model...
+ static_assert(std::invocable<T&, Args...>);
+ static_assert(std::invocable<const T&, Args...>);
+ static_assert(std::invocable<T, Args...>);
+ static_assert(std::invocable<const T, Args...>);
+
+ return true;
+}
+
+int a[10];
+
+static_assert(test(std::ranges::begin, a));
+static_assert(test(std::ranges::end, a));
+static_assert(test(std::ranges::cbegin, a));
+static_assert(test(std::ranges::cdata, a));
+static_assert(test(std::ranges::cend, a));
+static_assert(test(std::ranges::crbegin, a));
+static_assert(test(std::ranges::crend, a));
+static_assert(test(std::ranges::data, a));
+static_assert(test(std::ranges::empty, a));
+static_assert(test(std::ranges::rbegin, a));
+static_assert(test(std::ranges::rend, a));
+static_assert(test(std::ranges::size, a));
+static_assert(test(std::ranges::ssize, a));
+
+#if TEST_STD_VER >= 26
+// static_assert(test(std::views::reserve_hint, a));
+#endif
>From 48bdb7262ea94a64485e7c4d99f912d753698d1b Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34 at live.cn>
Date: Tue, 5 Aug 2025 17:22:43 +0800
Subject: [PATCH 2/2] Revert changes in `<ranges>`
---
libcxx/include/ranges | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/libcxx/include/ranges b/libcxx/include/ranges
index b86dd78ecb255..96d7a6b897188 100644
--- a/libcxx/include/ranges
+++ b/libcxx/include/ranges
@@ -405,14 +405,17 @@ namespace std {
# include <__config>
# if _LIBCPP_STD_VER >= 20
+# include <__ranges/access.h>
# include <__ranges/all.h>
# include <__ranges/common_view.h>
# include <__ranges/concepts.h>
# include <__ranges/counted.h>
# include <__ranges/dangling.h>
+# include <__ranges/data.h>
# include <__ranges/drop_view.h>
# include <__ranges/drop_while_view.h>
# include <__ranges/elements_view.h>
+# include <__ranges/empty.h>
# include <__ranges/empty_view.h>
# include <__ranges/enable_borrowed_range.h>
# include <__ranges/enable_view.h>
@@ -420,9 +423,12 @@ namespace std {
# include <__ranges/iota_view.h>
# include <__ranges/join_view.h>
# include <__ranges/lazy_split_view.h>
+# include <__ranges/rbegin.h>
# include <__ranges/ref_view.h>
+# include <__ranges/rend.h>
# include <__ranges/reverse_view.h>
# include <__ranges/single_view.h>
+# include <__ranges/size.h>
# include <__ranges/split_view.h>
# include <__ranges/subrange.h>
# include <__ranges/take_view.h>
@@ -454,7 +460,7 @@ namespace std {
// [ranges.syn]
# include <compare>
# include <initializer_list>
-# include <iterator> // some CPOs are provided in <iterator> per [range.access.general]
+# include <iterator>
// [tuple.helper]
# include <__tuple/tuple_element.h>
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