[libcxx-commits] [libcxx] [libcxx] P2278R4: implement `{basic_, }const_iterator`, and have `cbegin` et. al. return it (PR #99915)

[A. Jiang via libcxx-commits]

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@@ -61,6 +62,13 @@ concept borrowed_range =
 template <range _Rp>
 using sentinel_t = decltype(ranges::end(std::declval<_Rp&>()));
 
+#  if _LIBCPP_STD_VER >= 23
+template <range _Rp>
+using const_iterator_t = const_iterator<iterator_t<_Rp>>;
+template <range _Rp>
+using const_sentinel_t = const_sentinel<sentinel_t<_Rp>>;
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frederick-vs-ja wrote:

Should we implement [LWG3946](https://cplusplus.github.io/LWG/issue3946) together? (Or is it intended to leave it to be done in another PR?)
https://github.com/llvm/llvm-project/blob/445023f1739d3764f1dae6e6b7b0602328198a1e/libcxx/docs/Status/Cxx2cIssues.csv#L28



https://github.com/llvm/llvm-project/pull/99915