diff --git a/include/clang/Analysis/PathSensitive/GRWorkList.h b/include/clang/Analysis/PathSensitive/GRWorkList.h
index 934a559..857fa31 100644
--- a/include/clang/Analysis/PathSensitive/GRWorkList.h
+++ b/include/clang/Analysis/PathSensitive/GRWorkList.h
@@ -28,7 +28,7 @@
   ExplodedNode* Node;
   GRBlockCounter Counter;
   CFGBlock* Block;
-  unsigned BlockIdx;
+  unsigned BlockIdx; // This is the index of the next statement.
 
 public:
   GRWorkListUnit(ExplodedNode* N, GRBlockCounter C,