[Sema] Do not permit binding a reference to a compound literal

We could probably make this work if we cared enough.  However, we are
far outside any language rules at this point.

This fixes PR21834.

llvm-svn: 235818

clang/lib/Sema/SemaInit.cpp

@@ -3438,6 +3438,11 @@ static void TryReferenceListInitialization(Sema &S,
     Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
     return;
   }
+  // Can't reference initialize a compound literal.
+  if (Entity.getKind() == InitializedEntity::EK_CompoundLiteralInit) {
+    Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
+    return;
+  }
 
   QualType DestType = Entity.getType();
   QualType cv1T1 = DestType->getAs<ReferenceType>()->getPointeeType();

clang/test/SemaCXX/cxx0x-initializer-references.cpp

@@ -125,3 +125,7 @@ namespace PR20844 {
   struct B { operator A&(); } b;
   A &a{b}; // expected-error {{excess elements}} expected-note {{in initialization of temporary of type 'PR20844::A'}}
 }
+
+namespace PR21834 {
+const int &a = (const int &){0}; // expected-error {{cannot bind to an initializer list}}
+}