--- a/graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/VirtualizerToolImpl.java	Fri Jun 07 13:36:44 2013 +0200
+++ b/graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/VirtualizerToolImpl.java	Fri Jun 07 13:44:00 2013 +0200
@@ -87,16 +87,24 @@
         ObjectState obj = (ObjectState) objectState;
         assert obj != null && obj.isVirtual() : "not virtual: " + obj;
         ObjectState valueState = state.getObjectState(value);
+        ValueNode newValue = value;
         if (valueState == null) {
-            obj.setEntry(index, getReplacedValue(value));
+            newValue = getReplacedValue(value);
+            assert obj.getEntry(index) == null || obj.getEntry(index).kind() == newValue.kind() || (isObjectEntry(obj.getEntry(index)) && isObjectEntry(newValue));
         } else {
-            ValueNode newValue = value;
             if (valueState.getState() != EscapeState.Virtual) {
                 newValue = valueState.getMaterializedValue();
+                assert newValue.kind() == Kind.Object;
+            } else {
+                newValue = valueState.getVirtualObject();
             }
-            assert obj.getEntry(index) == null || obj.getEntry(index).kind() == newValue.kind();
-            obj.setEntry(index, newValue);
+            assert obj.getEntry(index) == null || isObjectEntry(obj.getEntry(index));
         }
+        obj.setEntry(index, newValue);
+    }
+
+    private static boolean isObjectEntry(ValueNode value) {
+        return value.kind() == Kind.Object || value instanceof VirtualObjectNode;
     }
 
     @Override