[libc++] Implement D2351R0 "Mark all library static cast wrappers as [[nodiscard]]"
These [[nodiscard]] annotations are added as a conforming extension;
it's unclear whether the paper will actually be adopted and make them
mandatory, but they do seem like good ideas regardless.
https://isocpp.org/files/papers/D2351R0.pdf
This patch implements the paper's effect on:
- std::to_integer, std::to_underlying
- std::forward, std::move, std::move_if_noexcept
- std::as_const
- std::identity
The paper also affects (but libc++ does not yet have an implementation of):
- std::bit_cast
Differential Revision: https://reviews.llvm.org/D99895
GitOrigin-RevId: 4b7bad9eaea2233521a94f6b096aaa88dc584e23
diff --git a/docs/UsingLibcxx.rst b/docs/UsingLibcxx.rst
index 6bf67ce..0e6d92b 100644
--- a/docs/UsingLibcxx.rst
+++ b/docs/UsingLibcxx.rst
@@ -287,15 +287,15 @@
1. Backporting ``[[nodiscard]]`` to entities declared as such by the
standard in newer dialects, but not in the present one.
-2. Extended applications of ``[[nodiscard]]``, at the libraries discretion,
+2. Extended applications of ``[[nodiscard]]``, at the library's discretion,
applied to entities never declared as such by the standard.
Users may also opt-out of additional applications ``[[nodiscard]]`` using
additional macros.
Applications of the first form, which backport ``[[nodiscard]]`` from a newer
-dialect may be disabled using macros specific to the dialect it was added. For
-example ``_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17``.
+dialect, may be disabled using macros specific to the dialect in which it was
+added. For example, ``_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17``.
Applications of the second form, which are pure extensions, may be disabled
by defining ``_LIBCPP_DISABLE_NODISCARD_EXT``.
@@ -346,3 +346,10 @@
* ``unique``
* ``upper_bound``
* ``lock_guard``'s constructors
+* ``as_const``
+* ``forward``
+* ``move``
+* ``move_if_noexcept``
+* ``identity::operator()``
+* ``to_integer``
+* ``to_underlying``