[libcxx-commits] [libcxx] [libcxx] adds a size-based representation for `vector`'s unstable ABI (PR #155330)

[Louis Dionne via libcxx-commits]

================
@@ -760,10 +777,10 @@ class vector {
   };
 
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __base_destruct_at_end(pointer __new_last) _NOEXCEPT {
-    pointer __soon_to_be_end = this->__end_;
+    pointer __soon_to_be_end = __layout_.__end_ptr();
     while (__new_last != __soon_to_be_end)
-      __alloc_traits::destroy(this->__alloc_, std::__to_address(--__soon_to_be_end));
-    this->__end_ = __new_last;
+      __alloc_traits::destroy(this->__layout_.__alloc(), std::__to_address(--__soon_to_be_end));
+    __layout_.__set_boundary(__new_last);
----------------
ldionne wrote:

```suggestion
    __layout_.__set_end(__new_last);
```

https://github.com/llvm/llvm-project/pull/155330