[Clang] Fix a crash when trying to initialize an invalid aggregate.

[cor3ntin]

Summary

We did not return an error when failing to producing
a valid expression when performing the initialization of
an aggregate initialized with a parenthesized list of expressions.

This is a regression introduced in Clang 17.

Fixes #63278

[aaron.ballman]

Precommit CI found issues with the newly added test that should be addressed.

clang/docs/ReleaseNotes.rst

633–634 ↗

(On Diff #537269)

This is a new regression introduced in Clang 17, so I don't think we need a release note, right?

clang/lib/Sema/SemaInit.cpp

9390

Please spell out the type (and make it a const pointer if possible).

clang/test/SemaCXX/paren-list-agg-init.cpp

281

Probably worth it to add a static auto y = 1; case as well?

[cor3ntin]

Address Aaron's Feedback

[aaron.ballman]

LGTM

clang/lib/Sema/SemaInit.cpp

case SK_ParenthesizedListInit: {
         *ResultType = CurInit.get()->getType();
       if (shouldBindAsTemporary(Entity))
         CurInit = S.MaybeBindToTemporary(CurInit.get());
       break;
     }
     }
   }
 
+  Expr *Init = CurInit.get();
+  if (!Init)
+    return ExprError();
+
   // Check whether the initializer has a shorter lifetime than the initialized
   // entity, and if not, either lifetime-extend or warn as appropriate.
-  if (auto *Init = CurInit.get())
-    S.checkInitializerLifetime(Entity, Init);
 
   // Diagnose non-fatal problems with the completed initialization.
   if (InitializedEntity::EntityKind EK = Entity.getKind();
       (EK == InitializedEntity::EK_Member ||
        EK == InitializedEntity::EK_ParenAggInitMember) &&
       cast<FieldDecl>(Entity.getDecl())->isBitField())
     S.CheckBitFieldInitialization(Kind.getLocation(),
-                                  cast<FieldDecl>(Entity.getDecl()),
-                                  CurInit.get());
+                                  cast<FieldDecl>(Entity.getDecl()), Init);
 
   // Check for std::move on construction.
-  if (const Expr *E = CurInit.get()) {
-    CheckMoveOnConstruction(S, E,
-                            Entity.getKind() == InitializedEntity::EK_Result);
-  }
+  CheckMoveOnConstruction(S, Init,
 
-  return CurInit;
+  return Init;
 }
 
 /// Somewhere within T there is an uninitialized reference subobject.
 /// Dig it out and diagnose it.
 static bool DiagnoseUninitializedReference(Sema &S, SourceLocation Loc,
                                            QualType T) {
   if (T->isReferenceType()) {
     S.Diag(Loc, diag::err_reference_without_init)

clang/test/SemaCXX/paren-list-agg-init.cpp

 // expected-error@-1 {{reference member of type 'int &&' uninitialized}}
 }
 
 namespace gh63008 {
 auto a = new A('a', {1.1});
 // expected-warning@-1 {{braces around scalar init}}
 // beforecxx20-warning@-2 {{aggregate initialization of type 'A' from a parenthesized list of values is a C++20 extension}}
 }
+
+
+namespace GH63278 {
+struct S {
+  int a = 0;
+  int b {0};
+  auto x = 1; // expected-error {{'auto' not allowed in non-static struct member}}
+  static const auto y = 1;
+};
+
+int test() {
+  // used to crash
+  S a(0, 1);
+  S b(0);
+  S c(0, 0, 1); // beforecxx20-warning {{aggregate initialization of type 'S' from a parenthesized list of values is a C++20 extension}}
+
+  S d {0, 1};
+  S e {0};
+  S f {0, 0, 1};
+}
+
+}