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

third_party/WebKit/Source/wtf/HashSet.h

 /*
  * Copyright (C) 2005, 2006, 2007, 2008, 2011 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 45 matching lines @@
                     ValueTraits,
                     Allocator>
       HashTableType;
 
  public:
   typedef HashTableConstIteratorAdapter<HashTableType, ValueTraits> iterator;
   typedef HashTableConstIteratorAdapter<HashTableType, ValueTraits>
       const_iterator;
   typedef typename HashTableType::AddResult AddResult;
 
-  HashSet() = default;
+  HashSet() {
+    static_assert(Allocator::isGarbageCollected ||
+                      !IsPointerToGarbageCollectedType<ValueArg>::value,
+                  "Cannot put raw pointers to garbage-collected classes into "
+                  "an off-heap HashSet. Use HeapHashSet<Member<T>> instead.");
+  }
   HashSet(const HashSet&) = default;
   HashSet& operator=(const HashSet&) = default;
   HashSet(HashSet&&) = default;
   HashSet& operator=(HashSet&&) = default;
 
   HashSet(std::initializer_list<ValueType> elements);
   HashSet& operator=(std::initializer_list<ValueType> elements);
 
   void swap(HashSet& ref) { m_impl.swap(ref.m_impl); }
 
@@ skipping 238 matching lines @@
   iterator end = collection.end();
   for (unsigned i = 0; it != end; ++it, ++i)
     vector[i] = *it;
 }
 
 }  // namespace WTF
 
 using WTF::HashSet;
 
 #endif  // WTF_HashSet_h