diff --git a/mps/code/trace.c b/mps/code/trace.c
index 14f8cc72c7c..cdf04b4a88e 100644
--- a/mps/code/trace.c
+++ b/mps/code/trace.c
@@ -846,7 +846,7 @@ static void traceFlip(Trace trace)
 static void traceCopySizes(Trace trace)
 {
   Ring node, nextNode;
-  int i;
+  Index i;
   Arena arena = trace->arena;
 
   RING_FOR(node, &arena->chainRing, nextNode) {