diff -r ef0373b55136 -r 758a864f9613 src/corelib/tools/qmap.h
--- a/src/corelib/tools/qmap.h	Fri Sep 17 08:34:18 2010 +0300
+++ b/src/corelib/tools/qmap.h	Mon Oct 04 01:19:32 2010 +0300
@@ -426,10 +426,11 @@
 Q_INLINE_TEMPLATE QMap<Key, T> &QMap<Key, T>::operator=(const QMap<Key, T> &other)
 {
     if (d != other.d) {
-        other.d->ref.ref();
+        QMapData* o = other.d;
+        o->ref.ref();
         if (!d->ref.deref())
             freeData(d);
-        d = other.d;
+        d = o;
         if (!d->sharable)
             detach_helper();
     }