3 files changed, 45 insertions, 7 deletions
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index ff0fe9d6b6..9adcf1c81f 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -437,6 +437,17 @@ TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
   return 0;
 }
 
+ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
+                                             SourceLocation EllipsisLoc) const {
+  assert(Kind == Template && 
+         "Only template template arguments can be pack expansions here");
+  assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
+         "Template template argument pack expansion without packs");
+  ParsedTemplateArgument Result(*this);
+  Result.EllipsisLoc = EllipsisLoc;
+  return Result;
+}
+
 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
                                             const ParsedTemplateArgument &Arg) {
   
@@ -456,9 +467,11 @@ static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
     
   case ParsedTemplateArgument::Template: {
     TemplateName Template = Arg.getAsTemplate().get();
-    return TemplateArgumentLoc(TemplateArgument(Template),
+    return TemplateArgumentLoc(TemplateArgument(Template,
+                                                Arg.getEllipsisLoc().isValid()),
                                Arg.getScopeSpec().getRange(),
-                               Arg.getLocation());
+                               Arg.getLocation(),
+                               Arg.getEllipsisLoc());
   }
   }
   
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 18bfee301b..a72a29378a 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -1344,19 +1344,20 @@ getTrivialTemplateArgumentLoc(Sema &S,
     
   case TemplateArgument::Declaration: {
     Expr *E
-    = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
+      = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
     .takeAs<Expr>();
     return TemplateArgumentLoc(TemplateArgument(E), E);
   }
     
   case TemplateArgument::Integral: {
     Expr *E
-    = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>();
+      = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).takeAs<Expr>();
     return TemplateArgumentLoc(TemplateArgument(E), E);
   }
     
   case TemplateArgument::Template:
-    return TemplateArgumentLoc(Arg, SourceRange(), Loc);
+    return TemplateArgumentLoc(Arg, SourceRange(), Loc,
+                               Arg.isPackExpansion()? Loc : SourceLocation());
     
   case TemplateArgument::Expression:
     return TemplateArgumentLoc(Arg, Arg.getAsExpr());
diff --git a/lib/Sema/SemaTemplateVariadic.cpp b/lib/Sema/SemaTemplateVariadic.cpp
index acb73144d9..fb88bd114b 100644
--- a/lib/Sema/SemaTemplateVariadic.cpp
+++ b/lib/Sema/SemaTemplateVariadic.cpp
@@ -130,6 +130,22 @@ namespace {
 
       return true; 
     }
+
+    /// \brief Suppress traversal of template argument pack expansions.
+    bool TraverseTemplateArgument(const TemplateArgument &Arg) {
+      if (Arg.isPackExpansion())
+        return true;
+
+      return inherited::TraverseTemplateArgument(Arg);
+    }
+
+    /// \brief Suppress traversal of template argument pack expansions.
+    bool TraverseTemplateArgumentLoc(const TemplateArgumentLoc &ArgLoc) {
+      if (ArgLoc.getArgument().isPackExpansion())
+        return true;
+      
+      return inherited::TraverseTemplateArgumentLoc(ArgLoc);
+    }
   };
 }
 
@@ -335,8 +351,16 @@ Sema::ActOnPackExpansion(const ParsedTemplateArgument &Arg,
   }
     
   case ParsedTemplateArgument::Template:
-    Diag(EllipsisLoc, diag::err_pack_expansion_unsupported);
-    return ParsedTemplateArgument();
+    if (!Arg.getAsTemplate().get().containsUnexpandedParameterPack()) {
+      SourceRange R(Arg.getLocation());
+      if (Arg.getScopeSpec().isValid())
+        R.setBegin(Arg.getScopeSpec().getBeginLoc());
+      Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
+        << R;
+      return ParsedTemplateArgument();
+    }
+      
+    return Arg.getTemplatePackExpansion(EllipsisLoc);
   }
   llvm_unreachable("Unhandled template argument kind?");
   return ParsedTemplateArgument();