Disallow off-heap containers containing raw on-heap pointers.

third_party/WebKit/Source/wtf/HashCountedSet.h

 /*
  * Copyright (C) 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 35 matching lines @@
                   HashTraits<unsigned>,
                   Allocator>
       ImplType;
 
  public:
   typedef Value ValueType;
   typedef typename ImplType::iterator iterator;
   typedef typename ImplType::const_iterator const_iterator;
   typedef typename ImplType::AddResult AddResult;
 
-  HashCountedSet() {}
+  HashCountedSet() {
+    static_assert(Allocator::isGarbageCollected ||
+                      !IsPointerToGarbageCollectedType<Value>::value,
+                  "Cannot put raw pointers to garbage-collected classes into "
+                  "an off-heap HashCountedSet. Use "
+                  "HeapHashCountedSet<Member<T>> instead.");
+  }
 
   void swap(HashCountedSet& other) { m_impl.swap(other.m_impl); }
 
   unsigned size() const { return m_impl.size(); }
   unsigned capacity() const { return m_impl.capacity(); }
   bool isEmpty() const { return m_impl.isEmpty(); }
 
   // Iterators iterate over pairs of values (called key) and counts (called
   // value).
   iterator begin() { return m_impl.begin(); }
@@ skipping 104 matching lines @@
   Vector<T> vector;
   copyToVector(*this, vector);
   return vector;
 }
 
 }  // namespace WTF
 
 using WTF::HashCountedSet;
 
 #endif  // WTF_HashCountedSet_h