1 files changed, 21 insertions, 0 deletions
diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index e99a67d1e3..25029afe1f 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -509,6 +509,25 @@ private:
     static void deleteNode2(QHashData::Node *node);
 
     static void duplicateNode(QHashData::Node *originalNode, void *newNode);
+
+    bool isValidIterator(const iterator &it) const
+    {
+#if defined(QT_DEBUG) && !defined(Q_HASH_NO_ITERATOR_DEBUG)
+        union {
+            QHashData *iteratorHashData;
+            QHashData::Node *node;
+        };
+        node = it.i;
+        while (node->next)
+            node = node->next;
+
+        return (iteratorHashData == d);
+#else
+        Q_UNUSED(it);
+        return true;
+#endif
+    }
+    friend class QSet<Key>;
 };
 
 
@@ -831,6 +850,8 @@ Q_OUTOFLINE_TEMPLATE T QHash<Key, T>::take(const Key &akey)
 template <class Key, class T>
 Q_OUTOFLINE_TEMPLATE typename QHash<Key, T>::iterator QHash<Key, T>::erase(iterator it)
 {
+    Q_ASSERT_X(isValidIterator(it), "QHash::erase", "The specified const_iterator argument 'it' is invalid");
+
     if (it == iterator(e))
         return it;