From 76e954bc367b681348e27cc430c6e0b97a22f9d9 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Sun, 5 Jul 2015 01:23:32 +0200
Subject: [PATCH] add reference to issue #1920

---
 src/babel/transformation/transformers/es6/classes/vanilla.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/babel/transformation/transformers/es6/classes/vanilla.js b/src/babel/transformation/transformers/es6/classes/vanilla.js
index 421e9f948b..db0845a05f 100644
--- a/src/babel/transformation/transformers/es6/classes/vanilla.js
+++ b/src/babel/transformation/transformers/es6/classes/vanilla.js
@@ -53,6 +53,7 @@ var verifyConstructorVisitor = {
   ThisExpression(node, parent, scope, state) {
     if (state.isDerived && !state.hasBareSuper) {
       if (this.inShadow()) {
+        // https://github.com/babel/babel/issues/1920
         var thisAlias = state.constructorPath.getData("this");
 
         if (!thisAlias) {