From 4cc844f410d7480cd10be76061d5f177c83e3a6a Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Tue, 9 Jun 2015 04:04:14 +0100
Subject: [PATCH] take into consideration assignment expressions in loop heads
 when replacing let references - fixes #1707

---
 src/babel/transformation/transformers/es6/block-scoping.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/babel/transformation/transformers/es6/block-scoping.js b/src/babel/transformation/transformers/es6/block-scoping.js
index 558e160039..76c13bf957 100644
--- a/src/babel/transformation/transformers/es6/block-scoping.js
+++ b/src/babel/transformation/transformers/es6/block-scoping.js
@@ -116,6 +116,13 @@ function traverseReplace(node, parent, scope, remaps) {
     replace(node, parent, scope, remaps);
   }
 
+  if (t.isAssignmentExpression(node)) {
+    var ids = t.getBindingIdentifiers(node);
+    for (var name in ids) {
+      replace(ids[name], parent, scope, remaps);
+    }
+  }
+
   scope.traverse(node, replaceVisitor, remaps);
 }