Cannot use Handle<T>::cast in Unique<T>::cast since it will try to do a T::cast (and its typecheck)…

src/lookup.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_LOOKUP_H_
 #define V8_LOOKUP_H_
 
 #include "src/factory.h"
 #include "src/isolate.h"
 #include "src/objects.h"
@@ skipping 120 matching lines @@
   bool IsConfigurable() const { return property_details().IsConfigurable(); }
   bool IsReadOnly() const { return property_details().IsReadOnly(); }
   Representation representation() const {
     return property_details().representation();
   }
   FieldIndex GetFieldIndex() const;
   Handle<HeapType> GetFieldType() const;
   int GetAccessorIndex() const;
   int GetConstantIndex() const;
   Handle<PropertyCell> GetPropertyCell() const;
-  Handle<PropertyCell> GetTransitionPropertyCell() const {
-    DCHECK_EQ(TRANSITION, state_);
-    return Handle<PropertyCell>::cast(transition_);
-  }
   Handle<Object> GetAccessors() const;
   Handle<Object> GetDataValue() const;
   // Usually returns the value that was passed in, but may perform
   // non-observable modifications on it, such as internalize strings.
   Handle<Object> WriteDataValue(Handle<Object> value);
   void InternalizeName();
 
  private:
   enum class InterceptorState {
     kUninitialized,
@@ skipping 59 matching lines @@
   Handle<JSReceiver> holder_;
   Handle<Map> holder_map_;
   const Handle<JSReceiver> initial_holder_;
   int number_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LOOKUP_H_