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+Section: 26.7.16.4 [range.lazy.split.outer.value] Status: New + Submitter: Hewill Kang Opened: 2023-11-11 Last modified: 2023-11-18
+Priority: Not Prioritized +
+View all other issues in [range.lazy.split.outer.value].
+View all issues with New status.
+Discussion:
++After P2325, there is no reason for lazy_split_view::outer-iterator::value_type +to provide a default constructor, which only leads to unexpected behavior: +
+
+#include <ranges>
+
+constexpr int arr[] = {42};
+constexpr auto split = arr | std::views::lazy_split(0);
+static_assert(!std::ranges::range_value_t<decltype(split)>{}); // UB, dereferencing a null pointer
++Also, the other constructor should be private because it makes no sense for the user to construct it arbitrarily, +which is not the intention. +
+ + +Proposed resolution:
++This wording is relative to N4964. +
+ +Modify 26.7.16.4 [range.lazy.split.outer.value], class split_view::outer-iterator::value_type synopsis, +as indicated:
+ +
+namespace std::ranges {
+ template<input_range V, forward_range Pattern>
+ requires view<V> && view<Pattern> &&
+ indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to> &&
+ (forward_range<V> || tiny-range<Pattern>)
+ template<bool Const>
+ struct lazy_split_view<V, Pattern>::outer-iterator<Const>::value_type
+ : view_interface<value_type> {
+ private:
+ outer-iterator i_ = outer-iterator(); // exposition only
+
+ constexpr explicit value_type(outer-iterator i); // exposition only
+
+ public:
+ value_type() = default;
+ constexpr explicit value_type(outer-iterator i);
+
+ constexpr inner-iterator<Const> begin() const;
+ constexpr default_sentinel_t end() const noexcept;
+ };
+}
+Revised 2023-11-18 at 12:52:04 UTC
+Revised 2023-11-18 at 13:06:00 UTC
Reference ISO/IEC IS 14882:2020(E)
Also see:
@@ -182,15 +182,15 @@Section: 26.7.16.4 [range.lazy.split.outer.value] Status: New + Submitter: Hewill Kang Opened: 2023-11-11 Last modified: 2023-11-18
+Priority: Not Prioritized +
+View all other issues in [range.lazy.split.outer.value].
+View all issues with New status.
+Discussion:
++After P2325, there is no reason for lazy_split_view::outer-iterator::value_type +to provide a default constructor, which only leads to unexpected behavior: +
+
+#include <ranges>
+
+constexpr int arr[] = {42};
+constexpr auto split = arr | std::views::lazy_split(0);
+static_assert(!std::ranges::range_value_t<decltype(split)>{}); // UB, dereferencing a null pointer
++Also, the other constructor should be private because it makes no sense for the user to construct it arbitrarily, +which is not the intention. +
+ + +Proposed resolution:
++This wording is relative to N4964. +
+ +Modify 26.7.16.4 [range.lazy.split.outer.value], class split_view::outer-iterator::value_type synopsis, +as indicated:
+ +
+namespace std::ranges {
+ template<input_range V, forward_range Pattern>
+ requires view<V> && view<Pattern> &&
+ indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to> &&
+ (forward_range<V> || tiny-range<Pattern>)
+ template<bool Const>
+ struct lazy_split_view<V, Pattern>::outer-iterator<Const>::value_type
+ : view_interface<value_type> {
+ private:
+ outer-iterator i_ = outer-iterator(); // exposition only
+
+ constexpr explicit value_type(outer-iterator i); // exposition only
+
+ public:
+ value_type() = default;
+ constexpr explicit value_type(outer-iterator i);
+
+ constexpr inner-iterator<Const> begin() const;
+ constexpr default_sentinel_t end() const noexcept;
+ };
+}
+