[clang] Fix overly aggressive lifetime checks for parenthesized aggregate initialization

Before this patch, initialized class members would have the LifetimeKind
LK_MemInitializer, which does not allow for binding a temporary to a
reference. Binding to a temporary however is allowed in parenthesized
aggregate initialization, even if it leads to a dangling reference. To
fix this, we create a new EntityKind, EK_ParenAggInitMember, which has
LifetimeKind LK_FullExpression.

This patch does *not* attempt to diagnose dangling references as a
result of using this feature.

This patch also refactors TryOrBuildParenListInitialization(...) to
accomodate creating different InitializedEntity objects.

Fixes #61567

[0]: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p0960r3.html

Reviewed By: shafik

Differential Revision: https://reviews.llvm.org/D148274

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaAccess.cpp b/clang/lib/Sema/SemaAccess.cpp
index cbda624..4a39c2d 100644
--- a/clang/lib/Sema/SemaAccess.cpp
+++ b/clang/lib/Sema/SemaAccess.cpp
@@ -1651,7 +1651,8 @@ Sema::AccessResult Sema::CheckConstructorAccess(SourceLocation UseLoc,
        << Entity.getBaseSpecifier()->getType() << getSpecialMember(Constructor);
     break;
 
-  case InitializedEntity::EK_Member: {
+  case InitializedEntity::EK_Member:
+  case InitializedEntity::EK_ParenAggInitMember: {
     const FieldDecl *Field = cast<FieldDecl>(Entity.getDecl());
     PD = PDiag(diag::err_access_field_ctor);
     PD << Field->getType() << getSpecialMember(Constructor);