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Showing content from https://cplusplus.github.io/LWG/issue4184 below:

Domain of ranges::cmeow doesn't match ranges::meow

This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of Tentatively NAD status.

4184. Domain of ranges::cmeow doesn't match ranges::meow

Section: 25.3 [range.access] Status: Tentatively NAD Submitter: Hewill Kang Opened: 2024-12-17 Last modified: 2025-02-07

Priority: Not Prioritized

View all issues with Tentatively NAD status.

Discussion:

ranges::begin/rbegin/data can be used on non-ranges as long as the object has a begin/rbegin/data member, this is also true for their const versions before C++23.

However, in C++23 the const version always applied possibly-const-range to the object, which no longer worked for non-ranges due to this function requiring input_range, which seems to be a breaking change (demo): 
#include <ranges>

struct NotRange {
        int* begin();
  const int* begin() const;
        int* rbegin();
  const int* rbegin() const;
        int* data();
  const int* data() const;
};

int main() {
  NotRange r;

  (void) std::ranges::begin(r);
  (void) std::ranges::rbegin(r);
  (void) std::ranges::data(r);

  // The following works in C++20, fails in C++23
  (void) std::ranges::cbegin(r);
  (void) std::ranges::crbegin(r);
  (void) std::ranges::cdata(r);
}

[2025-02-07; Reflector poll: NAD]

"We don't need to support ranges::cbegin on non-ranges."

"Seems to be very similar to LWG 3913(i) which LWG closed as NAD."

Proposed resolution:

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