--- a/Behavior.st	Wed Mar 28 09:51:58 2018 +0100
+++ b/Behavior.st	Fri Apr 13 09:37:08 2018 +0100
@@ -4535,7 +4535,7 @@
 %{
     INT nBytes = __intVal(nInstvars) * sizeof(OBJ) + OHDR_SIZE;
     if (__isSmallInteger(n)) {
-	int nIndex;
+	unsigned INT nIndex;
 
 	nIndex = __intVal(n);
 	switch (__intVal(__INST(flags)) & ARRAYMASK) {