Make the InjectedClassNameType the canonical type of the current instantiation
of a class template or class template partial specialization.  That is to
say, in
  template <class T> class A { ... };
or
  template <class T> class B<const T*> { ... };
make 'A<T>' and 'B<const T*>' sugar for the corresponding InjectedClassNameType
when written inside the appropriate context.  This allows us to track the
current instantiation appropriately even inside AST routines.  It also allows
us to compute a DeclContext for a type much more efficiently, at some extra
cost every time we write a template specialization (which can be optimized,
but I've left it simple in this patch).

llvm-svn: 102407
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index b449398..e3d30a0 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -186,7 +186,7 @@
   for (partial_spec_iterator P = getPartialSpecializations().begin(),
                           PEnd = getPartialSpecializations().end();
        P != PEnd; ++P) {
-    if (Context.hasSameType(Context.getTypeDeclType(&*P), T))
+    if (Context.hasSameType(P->getInjectedSpecializationType(), T))
       return &*P;
   }