Implement more of C++0x [temp.arg.explicit]p9, allowing extension of

pack expansions in template argument lists and function parameter
lists. The implementation of this paragraph should be complete
*except* for cases where we're substituting into one of the unexpanded
packs in a pack expansion; that's a general issue I haven't solved yet.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@123188 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 26 insertions, 2 deletions

diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 7eee444174..bc1ac1e6ae 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -2850,7 +2850,20 @@ bool TreeTransform<Derived>::TransformTemplateArguments(InputIterator First,
         Outputs.addArgument(Out);
       }
       
-      // FIXME: Variadic templates retain expansion!
+      // If we're supposed to retain a pack expansion, do so by temporarily
+      // forgetting the partially-substituted parameter pack.
+      if (RetainExpansion) {
+        ForgetPartiallySubstitutedPackRAII Forget(getDerived());
+        
+        if (getDerived().TransformTemplateArgument(Pattern, Out))
+          return true;
+        
+        Out = getDerived().RebuildPackExpansion(Out, Ellipsis);
+        if (Out.getArgument().isNull())
+          return true;
+        
+        Outputs.addArgument(Out);
+      }
       
       continue;
     }
@@ -3564,7 +3577,18 @@ bool TreeTransform<Derived>::
         continue;
       }
       
-      // FIXME: Variadic templates retain pack expansion!
+      // If we're supposed to retain a pack expansion, do so by temporarily
+      // forgetting the partially-substituted parameter pack.
+      if (RetainExpansion) {
+        ForgetPartiallySubstitutedPackRAII Forget(getDerived());
+        QualType NewType = getDerived().TransformType(Pattern);
+        if (NewType.isNull())
+          return true;
+        
+        OutParamTypes.push_back(NewType);
+        if (PVars)
+          PVars->push_back(0);
+      }
 
       // We'll substitute the parameter now without expanding the pack 
       // expansion.