Implement partial ordering of class template partial specializations

and function templates that contain variadic templates. This involves
three small-ish changes:

  (1) When transforming a pack expansion, if the transformed argument
  still contains unexpanded parameter packs, build a pack
  expansion. This can happen during the substitution that occurs into
  class template partial specialiation template arguments during
  partial ordering. 
 
  (2) When performing template argument deduction where the argument
  is a pack expansion, match against the pattern of that pack
  expansion.

  (3) When performing template argument deduction against a non-pack
  parameter, or a non-expansion template argument, deduction fails if
  the argument itself is a pack expansion (C++0x
  [temp.deduct.type]p22).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123279 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index bc1ac1e6ae..e63cc7da7c 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -2327,6 +2327,12 @@ bool TreeTransform<Derived>::TransformExprs(Expr **Inputs,
         if (Out.isInvalid())
           return true;
 
+        if (Out.get()->containsUnexpandedParameterPack()) {
+          Out = RebuildPackExpansion(Out.get(), Expansion->getEllipsisLoc());
+          if (Out.isInvalid())
+            return true;
+        }
+        
         if (ArgChanged)
           *ArgChanged = true;  
         Outputs.push_back(Out.get());
@@ -2847,6 +2853,12 @@ bool TreeTransform<Derived>::TransformTemplateArguments(InputIterator First,
         if (getDerived().TransformTemplateArgument(Pattern, Out))
           return true;
         
+        if (Out.getArgument().containsUnexpandedParameterPack()) {
+          Out = getDerived().RebuildPackExpansion(Out, Ellipsis);
+          if (Out.getArgument().isNull())
+            return true;
+        }
+          
         Outputs.addArgument(Out);
       }