diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/RangeCodegenUtil.java b/compiler/backend/src/org/jetbrains/jet/codegen/RangeCodegenUtil.java
index 988c48d4646..503e47984cc 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/RangeCodegenUtil.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/RangeCodegenUtil.java
@@ -50,6 +50,8 @@ public class RangeCodegenUtil {
 
     @Nullable
     public static BinaryCall getRangeAsBinaryCall(@NotNull JetForExpression forExpression) {
+        // We are looking for rangeTo() calls
+        // Other binary operations will succeed too, but will be filtered out later (by examining a resolvedCall)
         JetExpression rangeExpression = forExpression.getLoopRange();
         assert rangeExpression != null;
         JetExpression loopRange = JetPsiUtil.deparenthesize(rangeExpression);