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

runtime/vm/object.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "vm/assert.h"
 #include "vm/dart.h"
 #include "vm/globals.h"
@@ skipping 697 matching lines @@
   // Check if this type represents the 'Dynamic' type.
   bool IsDynamicType() const {
     return HasResolvedTypeClass() && (type_class() == Object::dynamic_class());
   }
 
   // Check if this type represents the 'void' type.
   bool IsVoidType() const {
     return HasResolvedTypeClass() && (type_class() == Object::void_class());
   }
 
+  bool IsObjectType() const {
+    return HasResolvedTypeClass() &&
+        Class::Handle(type_class()).IsObjectClass();
+  }
+
   // Check if this type represents the 'bool' interface.
   bool IsBoolInterface() const;
 
   // Check if this type represents the 'int' interface.
   bool IsIntInterface() const;
 
   // Check if this type represents the 'double' interface.
   bool IsDoubleInterface() const;
 
   // Check if this type represents the 'num' interface.
@@ skipping 2261 matching lines @@
 }
 
 
 void Context::SetAt(intptr_t index, const Instance& value) const {
   StorePointer(InstanceAddr(index), value.raw());
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_