Runtime type checking should be skipped for Object as destination type.

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 1325)
+++ runtime/vm/object.h	(working copy)
@@ -715,6 +715,11 @@
     return HasResolvedTypeClass() && (type_class() == Object::void_class());
   }
 
+  bool IsObjectType() const {
+    return HasResolvedTypeClass() &&
+        Class::Handle(type_class()).IsObjectClass();

[regis, 2011/11/08 21:18:10]

You can save a handle allocation with:
return HasResolvedTypeClass() && (type_class() == Object::object_class());

[srdjan, 2011/11/08 21:28:47]

Discussed offline and leaving it as it is (object class is store in object
store).

+  }
+
   // Check if this type represents the 'bool' interface.
   bool IsBoolInterface() const;