diff --git a/lib/6to5/traverse/index.js b/lib/6to5/traverse/index.js
index b8ef5ce920..5e56d891c4 100644
--- a/lib/6to5/traverse/index.js
+++ b/lib/6to5/traverse/index.js
@@ -55,7 +55,7 @@ function traverse(parent, callbacks, opts) {
 
       //
       var opts2 = { scope: opts.scope, blacklist: opts.blacklist };
-      if (t.isScope(node)) opts2.scope = new Scope(opts.scope, node);
+      if (t.isScope(node)) opts2.scope = new Scope(node, opts.scope);
 
       // enter
       if (callbacks.enter) {
@@ -89,9 +89,10 @@ function traverse(parent, callbacks, opts) {
 
 traverse.removeProperties = function (tree) {
   var clear = function (node) {
+    delete node._scopeReferences;
     delete node.extendedRange;
-    delete node._scopeIds;
     delete node._parent;
+    delete node._scope;
     delete node.tokens;
     delete node.range;
     delete node.start;
diff --git a/lib/6to5/traverse/scope.js b/lib/6to5/traverse/scope.js
index 5851011487..3945900182 100644
--- a/lib/6to5/traverse/scope.js
+++ b/lib/6to5/traverse/scope.js
@@ -10,11 +10,15 @@ var FOR_KEYS = ["left", "init"];
  * This searches the current "scope" and collects all references/declarations
  * within.
  *
- * @param {Scope} [parent]
  * @param {Node} block
+ * @param {Scope} [parent]
  */
 
-function Scope(parent, block) {
+function Scope(block, parent) {
+  if (!parent && block._parent) {
+    parent = block._parent._scope;
+  }
+
   this.parent = parent;
   this.block  = block;
 
@@ -23,10 +27,10 @@ function Scope(parent, block) {
 
 Scope.prototype.getReferences = function () {
   var block = this.block;
-  if (block._scope) return block._scope;
+  if (block._scopeReferences) return block._scopeReferences;
 
   var self       = this;
-  var references = block._scope = {};
+  var references = block._scopeReferences = {};
 
   var add = function (node) {
     self.add(node, references);