[libc++] LWG4025: Move assignment operator of std::expected<cv void, E> should not be conditionally deleted

[xiaoyang-sde]

Introduction

This patch implements LWG4025: Move assignment operator of std::expected<cv void, E> should not be conditionally deleted.

Reference

• [expected.void.assign]
• LWG4025

Closes #105324

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Xiaoyang Liu (xiaoyang-sde)

Changes

Introduction

This patch implements LWG4025: Move assignment operator of std::expected<cv void, E> should not be conditionally deleted.

Reference

• [expected.void.assign]
• LWG4025

Closes #105324

---

Full diff: https://github.com/llvm/llvm-project/pull/109363.diff

1 Files Affected:

• (modified) libcxx/include/__expected/expected.h (-2)

diff --git a/libcxx/include/__expected/expected.h b/libcxx/include/__expected/expected.h
index f4ad455a19ea5e..e04e17d1ebe698 100644
--- a/libcxx/include/__expected/expected.h
+++ b/libcxx/include/__expected/expected.h
@@ -1493,8 +1493,6 @@ class expected<_Tp, _Err> : private __expected_void_base<_Err> {
     return *this;
   }
 
-  _LIBCPP_HIDE_FROM_ABI constexpr expected& operator=(expected&&) = delete;
-
   _LIBCPP_HIDE_FROM_ABI constexpr expected&
   operator=(expected&& __rhs) noexcept(is_nothrow_move_assignable_v<_Err> && is_nothrow_move_constructible_v<_Err>)
     requires(is_move_assignable_v<_Err> && is_move_constructible_v<_Err>)

[ldionne]

Please rebase onto main to re-trigger CI. The CI instability should be resolved now.