From fc7fc384c9d878c1f5b558a7116d0899c8538518 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Tue, 16 Dec 2014 08:06:56 +1100
Subject: [PATCH] add declaration/reference support to scope

---
 lib/6to5/traverse/index.js |  2 +-
 lib/6to5/traverse/scope.js | 49 +++++++++++++++++++++++---------------
 2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/lib/6to5/traverse/index.js b/lib/6to5/traverse/index.js
index 32bad31add..add0a38df1 100644
--- a/lib/6to5/traverse/index.js
+++ b/lib/6to5/traverse/index.js
@@ -93,9 +93,9 @@ function traverse(parent, callbacks, opts) {
 
 traverse.removeProperties = function (tree) {
   var clear = function (node) {
-    delete node._scopeReferences;
     delete node._declarations;
     delete node.extendedRange;
+    delete node._scopeInfo;
     delete node._parent;
     delete node._scope;
     delete node.tokens;
diff --git a/lib/6to5/traverse/scope.js b/lib/6to5/traverse/scope.js
index b2faeab838..603a33a823 100644
--- a/lib/6to5/traverse/scope.js
+++ b/lib/6to5/traverse/scope.js
@@ -18,9 +18,14 @@ function Scope(block, parent) {
   this.parent = parent;
   this.block  = block;
 
-  this.references = this.getReferences();
+  var info = this.getInfo();
+  this.references = info.references;
+  this.declarations = info.declarations;
 }
 
+var vars = require("jshint/src/vars");
+Scope.defaultDeclarations = _.flatten([vars.newEcmaIdentifiers, vars.node, vars.ecmaIdentifiers, vars.reservedVars].map(_.keys));
+
 Scope.add = function (node, references) {
   if (!node) return;
   _.defaults(references, t.getIds(node, true));
@@ -35,14 +40,17 @@ Scope.prototype.generateTemp = function (file, name) {
   return id;
 };
 
-Scope.prototype.getReferences = function () {
+Scope.prototype.getInfo = function () {
   var block = this.block;
-  if (block._scopeReferences) return block._scopeReferences;
+  if (block._scopeInfo) return block._scopeInfo;
 
-  var references = block._scopeReferences = {};
+  var info = block._scopeInfo = {};
+  var references = info.references = {};
+  var declarations = info.declarations = {};
 
-  var add = function (node) {
+  var add = function (node, reference) {
     Scope.add(node, references);
+    if (!reference) Scope.add(node, declarations);
   };
 
   // ForStatement - left, init
@@ -90,7 +98,7 @@ Scope.prototype.getReferences = function () {
       if (block.id && node === block.id) return;
 
       if (t.isIdentifier(node) && t.isReferenced(node, parent) && !scope.has(node.name)) {
-        add(node);
+        add(node, true);
       }
 
       // we've ran into a declaration!
@@ -110,7 +118,7 @@ Scope.prototype.getReferences = function () {
     });
   }
 
-  return references;
+  return info;
 };
 
 Scope.prototype.push = function (opts) {
@@ -137,26 +145,29 @@ Scope.prototype.add = function (node) {
   Scope.add(node, this.references);
 };
 
-Scope.prototype.get = function (id) {
-  return id && (this.getOwn(id) || this.parentGet(id));
+Scope.prototype.get = function (id, decl) {
+  return id && (this.getOwn(id, decl) || this.parentGet(id, decl));
 };
 
-Scope.prototype.getOwn = function (id) {
-  return _.has(this.references, id) && this.references[id];
+Scope.prototype.getOwn = function (id, decl) {
+  var refs = this.references;
+  if (decl) refs = this.declarations;
+  return _.has(refs, id) && refs[id];
 };
 
-Scope.prototype.parentGet = function (id) {
-  return this.parent && this.parent.get(id);
+Scope.prototype.parentGet = function (id, decl) {
+  return this.parent && this.parent.get(id, decl);
 };
 
-Scope.prototype.has = function (id) {
-  return id && (this.hasOwn(id) || this.parentHas(id));
+Scope.prototype.has = function (id, decl) {
+  return (id && (this.hasOwn(id, decl) || this.parentHas(id, decl))) ||
+         _.contains(Scope.defaultDeclarations, id);
 };
 
-Scope.prototype.hasOwn = function (id) {
-  return !!this.getOwn(id);
+Scope.prototype.hasOwn = function (id, decl) {
+  return !!this.getOwn(id, decl);
 };
 
-Scope.prototype.parentHas = function (id) {
-  return this.parent && this.parent.has(id);
+Scope.prototype.parentHas = function (id, decl) {
+  return this.parent && this.parent.has(id, decl);
 };