[libcxx-commits] [libcxx] [libc++] Destroy elements when exceptions are thrown in __construct_at_end (PR #167112)

[A. Jiang via libcxx-commits]

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@@ -142,6 +143,20 @@ uninitialized_fill_n(_ForwardIterator __first, _Size __n, const _Tp& __x) {
   return std::__uninitialized_fill_n<_ValueType>(__first, __n, __x);
 }
 
+// uninitialized_default_construct_n
+
+template <class _ValueType, class _ForwardIterator, class _Size>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+__uninitialized_default_construct_n(_ForwardIterator __first, _Size __n) {
+  auto __idx   = __first;
+  auto __guard = std::__make_exception_guard([&] { std::__destroy(__first, __idx); });
+  for (; __n > 0; ++__idx, (void)--__n)
+    std::__construct_at(std::addressof(*__idx));
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frederick-vs-ja wrote:

This is wrong. The function name contains `default_construct` and it intentionally performed default-initialization, but you changed it to perform value-initialization.

https://github.com/llvm/llvm-project/pull/167112