Introduce a new type, PackExpansionType, to capture types that are

pack expansions, e.g. given

  template<typename... Types> struct tuple;

  template<typename... Types>
  struct tuple_of_refs {
    typedef tuple<Types&...> types;
  };

the type of the "types" typedef is a PackExpansionType whose pattern
is Types&. 

This commit introduces support for creating pack expansions for
template type arguments, as above, but not for any other kind of pack
expansion, nor for any form of instantiation.

llvm-svn: 122223

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index da04b621985..d4e99e8ad94 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -2815,6 +2815,12 @@ MarkUsedTemplateParameters(Sema &SemaRef, QualType T,
                                  OnlyDeduced, Depth, Used);
     break;
 
+  case Type::PackExpansion:
+    MarkUsedTemplateParameters(SemaRef, 
+                               cast<PackExpansionType>(T)->getPattern(),
+                               OnlyDeduced, Depth, Used);
+    break;
+
   // None of these types have any template parameters in them.
   case Type::Builtin:
   case Type::VariableArray: