diff --git a/idea/src/org/jetbrains/jet/plugin/refactoring/changeSignature/JetChangeSignatureUsageProcessor.java b/idea/src/org/jetbrains/jet/plugin/refactoring/changeSignature/JetChangeSignatureUsageProcessor.java
index 3da566624e7..77b83d1665b 100644
--- a/idea/src/org/jetbrains/jet/plugin/refactoring/changeSignature/JetChangeSignatureUsageProcessor.java
+++ b/idea/src/org/jetbrains/jet/plugin/refactoring/changeSignature/JetChangeSignatureUsageProcessor.java
@@ -57,7 +57,11 @@ public class JetChangeSignatureUsageProcessor implements ChangeSignatureUsagePro
     @Override
     public UsageInfo[] findUsages(ChangeInfo info) {
         Set<UsageInfo> result = new HashSet<UsageInfo>();
-        findAllMethodUsages((JetChangeInfo)info, result);
+
+        if (info instanceof JetChangeInfo) {
+            findAllMethodUsages((JetChangeInfo)info, result);
+        }
+
         return result.toArray(new UsageInfo[result.size()]);
     }