[libcxx-commits] [libcxx] [libc++] Ensure that `std::expected` has no tail padding (PR #69673)

[Louis Dionne via libcxx-commits]

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In-Reply-To: <llvm/llvm-project/pull/69673/libcxx at github.com>


================
@@ -88,8 +88,263 @@ _LIBCPP_HIDE_FROM_ABI void __throw_bad_expected_access(_Arg&& __arg) {
 #  endif
 }
 
+struct __expected_invoke_tag {};
+
+template <bool _NoUnique, class _Tp>
+class __expected_conditional_no_unique_address {
----------------
ldionne wrote:

Let's add this comment:

```
// This class implements an object with `[[no_unique_address]]` conditionally applied to it,
// based on the value of `_NoUnique`.
//
// If we had a language feature, this class would basically be replaced by `[[no_unique_address(condition)]]`.
```

https://github.com/llvm/llvm-project/pull/69673