diff --git a/lucene/facet/src/java/org/apache/lucene/facet/FacetsCollector.java b/lucene/facet/src/java/org/apache/lucene/facet/FacetsCollector.java
index e17562a2063..11ccec5ca1b 100644
--- a/lucene/facet/src/java/org/apache/lucene/facet/FacetsCollector.java
+++ b/lucene/facet/src/java/org/apache/lucene/facet/FacetsCollector.java
@@ -84,7 +84,7 @@ public class FacetsCollector extends SimpleCollector {
     if (keepScores) {
       if (doc >= scores.length) {
         float[] newScores = new float[ArrayUtil.oversize(doc + 1, 4)];
-        System.arraycopy(scores, 0, newScores, 0, doc);
+        System.arraycopy(scores, 0, newScores, 0, scores.length);
         scores = newScores;
       }
       scores[doc] = scorer.score();