[libcxx] Implement c++2a char8_t input/output of std::filesystem::path
This implements the std::filesystem parts of P0482 (which is already
marked as in progress), and applies the actions that are suggested
in P1423.
Differential Revision: https://reviews.llvm.org/D90222
GitOrigin-RevId: 6be11e35d5397ae1c117eb840a969585fdd7d08d
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 719115f..8ce9b29 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -56,3 +56,9 @@
- ``ceil2`` has been renamed to ``bit_ceil``
- ``floor2`` has been renamed to ``bit_floor``
- ``log2p1`` has been renamed to ``bit_width``
+
+- In C++20 mode, ``std::filesystem::path::u8string()`` and
+ ``generic_u8string()`` now return ``std::u8string`` according to P0428,
+ while they return ``std::string`` in C++17. This can cause source
+ incompatibility, which is discussed and acknowledged in P1423, but that
+ paper doesn't suggest any remediation for this incompatibility.