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

[A. Jiang via libcxx-commits]

================
@@ -61,7 +61,7 @@
 "`P1899R3 <https://wg21.link/P1899R3>`__","``stride_view``","2022-07 (Virtual)","","",""
 "`P2093R14 <https://wg21.link/P2093R14>`__","Formatted output","2022-07 (Virtual)","|Complete|","18.0",""
 "`P2165R4 <https://wg21.link/P2165R4>`__","Compatibility between ``tuple``, ``pair`` and ``tuple-like`` objects","2022-07 (Virtual)","","",""
-"`P2278R4 <https://wg21.link/P2278R4>`__","``cbegin`` should always return a constant iterator","2022-07 (Virtual)","","",""
+"`P2278R4 <https://wg21.link/P2278R4>`__","``cbegin`` should always return a constant iterator","2022-07 (Virtual)","|Complete|","20.0","This paper is applied as DR against C++23 (MSVC STL and libstdc++ have done the same). The feature macro is not yet defined, since other features from the original paper have not been completed."
----------------
frederick-vs-ja wrote:

> Also, since this is a C++23 paper, it seems wrong to say that the paper is being applied as a DR against C++23. It's just a C++23 paper implemented in C++23 (and above). Or did I miss something?

Looks like that something was mistakenly duplicated in force-pushing. It was right in 160a204f24092aeffcb9674ce4c3093949301535.

```suggestion
"`P2278R4 <https://wg21.link/P2278R4>`__","``cbegin`` should always return a constant iterator","2022-07 (Virtual)","|In Progress|","20.0","``basic_const_iterator`` has been implemented, and the const range accessors (``cbegin``, ``cend``, ``crbegin``, ``crend``) have been updated to return this new type. However, the changes to ``cdata`` and ``span``, and ``const_view``, have not yet been implemented."
```

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