diff --git a/include/llvm/DerivedTypes.h b/include/llvm/DerivedTypes.h
index 179f44fbc07..e4b9136802a 100644
--- a/include/llvm/DerivedTypes.h
+++ b/include/llvm/DerivedTypes.h
@@ -31,7 +31,7 @@ class StructValType;
 class PointerValType;
 class PackedValType;
 
-class DerivedType : public Type, public AbstractTypeUser {
+class DerivedType : public Type {
   friend class Type;
 
 protected:
diff --git a/include/llvm/Type.h b/include/llvm/Type.h
index d69005865d2..68af106ffe4 100644
--- a/include/llvm/Type.h
+++ b/include/llvm/Type.h
@@ -51,7 +51,7 @@ class StructType;
 class PackedType;
 class TypeMapBase;
 
-class Type {
+class Type : public AbstractTypeUser {
 public:
   ///===-------------------------------------------------------------------===//
   /// Definitions of all of the base types for the Type system.  Based on this
@@ -341,6 +341,9 @@ private:
   /// their size is relatively uncommon, move this operation out of line.
   bool isSizedDerivedType() const;
 
+  virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
+  virtual void typeBecameConcrete(const DerivedType *AbsTy);
+
 protected:
   // PromoteAbstractToConcrete - This is an internal method used to calculate
   // change "Abstract" from true to false when types are refined.