From 0a25618c34eb15b3ad254d86b6ed8c8e78544ebf Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Thu, 20 Nov 2014 16:53:22 +1100
Subject: [PATCH] collect references that haven't been declared in scope -
 fixes #173 and fixes #175

---
 lib/6to5/traverse/scope.js | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/lib/6to5/traverse/scope.js b/lib/6to5/traverse/scope.js
index 6dd2433739..5851011487 100644
--- a/lib/6to5/traverse/scope.js
+++ b/lib/6to5/traverse/scope.js
@@ -6,25 +6,30 @@ var _        = require("lodash");
 
 var FOR_KEYS = ["left", "init"];
 
+/**
+ * This searches the current "scope" and collects all references/declarations
+ * within.
+ *
+ * @param {Scope} [parent]
+ * @param {Node} block
+ */
+
 function Scope(parent, block) {
   this.parent = parent;
   this.block  = block;
 
-  this.info         = this.getInfo();
-  this.declarations = this.info.declarations;
+  this.references = this.getReferences();
 }
 
-Scope.prototype.getInfo = function () {
+Scope.prototype.getReferences = function () {
   var block = this.block;
   if (block._scope) return block._scope;
 
-  var self = this;
-  var info = block._scope = {
-    declarations: {}
-  };
+  var self       = this;
+  var references = block._scope = {};
 
   var add = function (node) {
-    self.addDeclaration(node, info.declarations);
+    self.add(node, references);
   };
 
   // ForStatement - left, init
@@ -56,7 +61,7 @@ Scope.prototype.getInfo = function () {
   // Program, Function - var variables
 
   if (t.isProgram(block) || t.isFunction(block)) {
-    traverse(block, function (node) {
+    traverse(block, function (node, parent, scope) {
       if (t.isFor(node)) {
         _.each(FOR_KEYS, function (key) {
           var declar = node[key];
@@ -68,12 +73,16 @@ Scope.prototype.getInfo = function () {
       // declared within are accessible
       if (t.isFunction(node)) return false;
 
+      if (t.isIdentifier(node) && t.isReferenced(node, parent) && !scope.has(node.name)) {
+        add(node);
+      }
+
       // we've ran into a declaration!
       // we'll let the BlockStatement scope deal with `let` declarations
       if (t.isDeclaration(node) && !t.isLet(node)) {
         add(node);
       }
-    });
+    }, { scope: this });
   }
 
   // Function - params, rest
@@ -85,12 +94,12 @@ Scope.prototype.getInfo = function () {
     });
   }
 
-  return info;
+  return references;
 };
 
-Scope.prototype.addDeclaration = function (node, declarations) {
+Scope.prototype.add = function (node, references) {
   if (!node) return;
-  _.merge(declarations || this.declarations, t.getIds(node, true));
+  _.merge(references || this.references, t.getIds(node, true));
 };
 
 Scope.prototype.get = function (id) {
@@ -98,7 +107,7 @@ Scope.prototype.get = function (id) {
 };
 
 Scope.prototype.getOwn = function (id) {
-  return _.has(this.declarations, id) && this.declarations[id];
+  return _.has(this.references, id) && this.references[id];
 };
 
 Scope.prototype.parentGet = function (id) {