When we're building a CXXExprWithTemporaries, only include those

temporaries that are within our current evaluation context. That way,
nested evaluation contexts (e.g., within a sizeof() expression) won't
see temporaries from outer contexts. Also, make sure to push a new
evaluation context when instantiating the initializer of a variable;
this may be an unevaluated context or a potentially-evaluated context,
depending on whether it's an in-class initializer or not. Fixes PR5672.

llvm-svn: 90460

clang/lib/Sema/SemaExprCXX.cpp

@@ -2069,14 +2069,17 @@ Expr *Sema::MaybeCreateCXXExprWithTemporaries(Expr *SubExpr,
                                               bool ShouldDestroyTemps) {
   assert(SubExpr && "sub expression can't be null!");
 
-  if (ExprTemporaries.empty())
+  unsigned FirstTemporary = ExprEvalContexts.back().NumTemporaries;
+  assert(ExprTemporaries.size() >= FirstTemporary);
+  if (ExprTemporaries.size() == FirstTemporary)
     return SubExpr;
 
   Expr *E = CXXExprWithTemporaries::Create(Context, SubExpr,
-                                           &ExprTemporaries[0],
-                                           ExprTemporaries.size(),
+                                           &ExprTemporaries[FirstTemporary],
+                                    ExprTemporaries.size() - FirstTemporary,
                                            ShouldDestroyTemps);
-  ExprTemporaries.clear();
+  ExprTemporaries.erase(ExprTemporaries.begin() + FirstTemporary,
+                        ExprTemporaries.end());
 
   return E;
 }

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -193,6 +193,11 @@ Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
                                                      TSK_ImplicitInstantiation);
   
   if (D->getInit()) {
+    if (Var->isStaticDataMember() && !D->isOutOfLine())
+      SemaRef.PushExpressionEvaluationContext(Sema::Unevaluated);
+    else
+      SemaRef.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
+
     OwningExprResult Init
       = SemaRef.SubstExpr(D->getInit(), TemplateArgs);
     if (Init.isInvalid())
@@ -235,6 +240,7 @@ Decl *TemplateDeclInstantiator::VisitVarDecl(VarDecl *D) {
     } else
       SemaRef.AddInitializerToDecl(Sema::DeclPtrTy::make(Var), move(Init),
                                    D->hasCXXDirectInitializer());
+    SemaRef.PopExpressionEvaluationContext();
   } else if (!Var->isStaticDataMember() || Var->isOutOfLine())
     SemaRef.ActOnUninitializedDecl(Sema::DeclPtrTy::make(Var), false);
 

clang/lib/Sema/SemaType.cpp

@@ -897,6 +897,9 @@ QualType Sema::GetTypeForDeclarator(Declarator &D, Scope *S,
     break;
   }
   
+  if (T.isNull())
+    return T;
+
   if (T == Context.UndeducedAutoTy) {
     int Error = -1;
 

clang/test/SemaTemplate/instantiate-static-var.cpp

@@ -72,3 +72,23 @@ void Test() {
   Z1<Y2<X2>::value> x2;
   int y2[Y2<X2>::value];
 }
+
+// PR5672
+template <int n>
+struct X3 {};
+
+class Y3 {
+ public:
+  ~Y3();  // The error isn't triggered without this dtor.
+
+  void Foo(X3<1>);
+};
+
+template <typename T>
+struct SizeOf {
+  static const int value = sizeof(T);
+};
+
+void MyTest3() {
+   Y3().Foo(X3<SizeOf<char>::value>());
+}