Implement C++11 [expr.call]p11: If the operand to a decltype-specifier is a

function call (or a comma expression with a function call on its right-hand
side), possibly parenthesized, then the return type is not required to be
complete and a temporary is not bound. Other subexpressions inside a decltype
expression do not get this treatment.

This is implemented by deferring the relevant checks for all calls immediately
within a decltype expression, then, when the expression is fully-parsed,
checking the relevant constraints and stripping off any top-level temporary
binding.

Deferring the completion of the return type exposed a bug in overload
resolution where completion of the argument types was not attempted, which
is also fixed by this change.

llvm-svn: 151117

1 files changed, 6 insertions, 1 deletions

diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 7e775f55e0a..58d6a22a288 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -4305,12 +4305,17 @@ QualType TreeTransform<Derived>::TransformDecltypeType(TypeLocBuilder &TLB,
   const DecltypeType *T = TL.getTypePtr();
 
   // decltype expressions are not potentially evaluated contexts
-  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated, 0,
+                                               /*IsDecltype=*/ true);
 
   ExprResult E = getDerived().TransformExpr(T->getUnderlyingExpr());
   if (E.isInvalid())
     return QualType();
 
+  E = getSema().ActOnDecltypeExpression(E.take());
+  if (E.isInvalid())
+    return QualType();
+
   QualType Result = TL.getType();
   if (getDerived().AlwaysRebuild() ||
       E.get() != T->getUnderlyingExpr()) {