[clang] Reapply "[Clang][CWG1815] Support lifetime extension of temporary created by aggregate initialization using a default member initializer" (PR #97308)

[via cfe-commits]

================
@@ -7849,13 +7854,17 @@ class Sema final : public SemaBase {
   /// keepInLifetimeExtendingContext - Pull down InLifetimeExtendingContext
   /// flag from previous context.
   void keepInLifetimeExtendingContext() {
-    if (ExprEvalContexts.size() > 2 &&
-        parentEvaluationContext().InLifetimeExtendingContext) {
-      auto &LastRecord = ExprEvalContexts.back();
-      auto &PrevRecord = parentEvaluationContext();
-      LastRecord.InLifetimeExtendingContext =
-          PrevRecord.InLifetimeExtendingContext;
-    }
+    if (ExprEvalContexts.size() > 2)
+      currentEvaluationContext().InLifetimeExtendingContext =
+          parentEvaluationContext().InLifetimeExtendingContext;
+  }
+
+  /// keepInRebuildDefaultArgInitContext - Pull down
+  /// RebuildDefaultArgOrDefaultInit flag from previous context.
+  void keepInRebuildDefaultArgOrInitContext() {
+    if (ExprEvalContexts.size() > 2)
+      currentEvaluationContext().RebuildDefaultArgOrDefaultInit =
+          parentEvaluationContext().RebuildDefaultArgOrDefaultInit;
----------------
cor3ntin wrote:

Ditto

https://github.com/llvm/llvm-project/pull/97308