[Clang] Extend lifetime of temporaries in mem-default-init for P2718R0 (#86960)

Depends on [CWG1815](https://github.com/llvm/llvm-project/pull/108039).
Fixes https://github.com/llvm/llvm-project/issues/85613.

In [[Clang] Implement P2718R0 "Lifetime extension in range-based for
loops"](https://github.com/llvm/llvm-project/pull/76361), we've not
implement the lifetime extensions for the temporaries which in
`CXXDefaultInitExpr`. As the confirmation in
https://github.com/llvm/llvm-project/issues/85613, we should extend
lifetime for that.

To avoid modifying current CodeGen rules, in a lifetime extension
context, the cleanup of `CXXDefaultInitExpr` was ignored.

---------

Signed-off-by: yronglin <yronglin777@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index edd1fe4..5d6a586 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -763,6 +763,8 @@ void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
         SemaRef.currentEvaluationContext().DelayedDefaultInitializationContext =
             SemaRef.parentEvaluationContext()
                 .DelayedDefaultInitializationContext;
+        SemaRef.currentEvaluationContext().InLifetimeExtendingContext =
+            SemaRef.parentEvaluationContext().InLifetimeExtendingContext;
         DIE = SemaRef.BuildCXXDefaultInitExpr(Loc, Field);
       }
       if (DIE.isInvalid()) {