In List::Add, correctly handle the case of adding a reference to a...

src/list.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 35 matching lines @@
 template <typename T, class P>
 class List {
  public:
 
   INLINE(explicit List(int capacity)) { Initialize(capacity); }
   INLINE(~List()) { DeleteData(data_); }
 
   INLINE(void* operator new(size_t size)) { return P::New(size); }
   INLINE(void operator delete(void* p, size_t)) { return P::Delete(p); }
 
+  // Returns a reference to the element at index i.  This reference is
+  // not safe to use after operations that can change the list's
+  // backing store (eg, Add).
   inline T& operator[](int i) const  {
     ASSERT(0 <= i && i < length_);
     return data_[i];
   }
   inline T& at(int i) const  { return operator[](i); }
   inline T& last() const {
-    ASSERT(!is_empty());
     return at(length_ - 1);
   }
 
   INLINE(bool is_empty() const) { return length_ == 0; }
   INLINE(int length() const) { return length_; }
 
   Vector<T> ToVector() { return Vector<T>(data_, length_); }
 
   Vector<const T> ToConstVector() { return Vector<const T>(data_, length_); }
 
   // Adds a copy of the given 'element' to the end of the list,
   // expanding the list if necessary.
-  T& Add(const T& element);
+  void Add(const T& element);
 
   // Added 'count' elements with the value 'value' and returns a
   // vector that allows access to the elements.  The vector is valid
   // until the next change is made to this list.
-  Vector<T> AddBlock(const T& value, int count);
-
-  // Inserts a copy of the given element at index i in the list.  All
-  // elements formerly at or above i are moved up and the length of
-  // the list increases by one.  This function's complexity is linear
-  // in the size of the list.
-  T& Insert(int i, const T& element);
+  Vector<T> AddBlock(T value, int count);
 
   // Removes the i'th element without deleting it even if T is a
   // pointer type; moves all elements above i "down". Returns the
   // removed element.  This function's complexity is linear in the
   // size of the list.
   T Remove(int i);
 
   // Removes the last element without deleting it even if T is a
   // pointer type. Returns the removed element.
   INLINE(T RemoveLast()) { return Remove(length_ - 1); }
@@ skipping 24 matching lines @@
   INLINE(T* NewData(int n))  { return static_cast<T*>(P::New(n * sizeof(T))); }
   INLINE(void DeleteData(T* data))  { P::Delete(data); }
 
   DISALLOW_COPY_AND_ASSIGN(List);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LIST_H_