From 7868e77f8e2b3ec40005ea9f99738f1ff52b3d0a Mon Sep 17 00:00:00 2001
From: Sergey Pepyakin <sergei@parity.io>
Date: Mon, 1 Apr 2019 17:46:58 +0200
Subject: [PATCH] Add comment about safety of top_label

---
 src/validation/func.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/validation/func.rs b/src/validation/func.rs
index ddce429..1a3351b 100644
--- a/src/validation/func.rs
+++ b/src/validation/func.rs
@@ -1703,6 +1703,7 @@ fn pop_label(
 }
 
 fn top_label(frame_stack: &StackWithLimit<BlockFrame>) -> &BlockFrame {
+    // TODO: This actually isn't safe.
     frame_stack
         .top()
         .expect("this function can't be called with empty frame stack")