Introduce a new representation for template template

parameters. Rather than storing them as either declarations (for the
non-dependent case) or expressions (for the dependent case), we now
(always) store them as TemplateNames. 

The primary change here is to add a new kind of TemplateArgument,
which stores a TemplateName. However, making that change ripples to
every switch on a TemplateArgument's kind, also affecting
TemplateArgumentLocInfo/TemplateArgumentLoc, default template
arguments for template template parameters, type-checking of template
template arguments, etc.

This change is light on testing. It should fix several pre-existing
problems with template template parameters, such as:
  - the inability to use dependent template names as template template
  arguments
  - template template parameter default arguments cannot be
  instantiation

However, there are enough pieces missing that more implementation is
required before we can adequately test template template parameters. 

llvm-svn: 86777

1 files changed, 6 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 13a66aaca01..4f261383ade 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -1219,12 +1219,13 @@ addAssociatedClassesAndNamespaces(const TemplateArgument &Arg,
                                         AssociatedClasses);
       break;
 
-    case TemplateArgument::Declaration:
+    case TemplateArgument::Template: {
       // [...] the namespaces in which any template template arguments are
       // defined; and the classes in which any member templates used as
       // template template arguments are defined.
+      TemplateName Template = Arg.getAsTemplate();
       if (ClassTemplateDecl *ClassTemplate
-            = dyn_cast<ClassTemplateDecl>(Arg.getAsDecl())) {
+                 = dyn_cast<ClassTemplateDecl>(Template.getAsTemplateDecl())) {
         DeclContext *Ctx = ClassTemplate->getDeclContext();
         if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx))
           AssociatedClasses.insert(EnclosingClass);
@@ -1234,7 +1235,9 @@ addAssociatedClassesAndNamespaces(const TemplateArgument &Arg,
         CollectNamespace(AssociatedNamespaces, Ctx);
       }
       break;
-
+    }
+      
+    case TemplateArgument::Declaration:
     case TemplateArgument::Integral:
     case TemplateArgument::Expression:
       // [Note: non-type template arguments do not contribute to the set of