From 49a53b26bb06f54b138595b5526fe7cacbba85e9 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Tue, 10 Feb 2015 22:39:07 +1100
Subject: [PATCH] add scope renaming helper method - fixes #645 - @RReverser

---
 lib/6to5/transformation/modules/common.js |  9 +++-
 lib/6to5/traversal/scope.js               | 55 +++++++++++++++++++++--
 2 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/lib/6to5/transformation/modules/common.js b/lib/6to5/transformation/modules/common.js
index f2ce247b56..364aa11626 100644
--- a/lib/6to5/transformation/modules/common.js
+++ b/lib/6to5/transformation/modules/common.js
@@ -14,8 +14,15 @@ function CommonJSFormatter() {
 util.inherits(CommonJSFormatter, DefaultFormatter);
 
 CommonJSFormatter.prototype.init = function () {
+  var file  = this.file;
+  var scope = file.scope;
+
+  if (scope.hasBinding("module")) {
+    scope.rename("module", file.generateUidIdentifier("module").name);
+  }
+
   if (!this.noInteropRequireImport && this.hasNonDefaultExports) {
-    this.file.ast.program.body.push(util.template("exports-module-declaration", true));
+    file.ast.program.body.push(util.template("exports-module-declaration", true));
   }
 };
 
diff --git a/lib/6to5/traversal/scope.js b/lib/6to5/traversal/scope.js
index d155541b77..55c758ee5c 100644
--- a/lib/6to5/traversal/scope.js
+++ b/lib/6to5/traversal/scope.js
@@ -143,6 +143,35 @@ Scope.prototype.checkBlockScopedCollisions = function (kind, key, id) {
   }
 };
 
+Scope.prototype.rename = function (oldName, newName) {
+  var info = this.getBindingWithScope(oldName);
+  console.log(info);
+  if (!info) return;
+
+  var binding = info.binding;
+  var scope = info.scope;
+
+  scope.references[newName] = binding;
+  scope.bindings[newName] = binding;
+
+  delete scope.references[oldName];
+  delete scope.bindings[oldName];
+
+  binding.name = newName;
+
+  scope.traverse(scope.block, {
+    enter: function (node, parent, scope) {
+      if (t.isReferencedIdentifier(node, parent) && node.name === oldName) {
+        node.name = newName;
+      } else if (t.isScope(node)) {
+        if (t.getBinding(oldName) !== binding) {
+          this.skip();
+        }
+      }
+    }
+  });
+};
+
 Scope.prototype.inferType = function (node) {
   var target;
 
@@ -150,10 +179,6 @@ Scope.prototype.inferType = function (node) {
     target = node.init;
   }
 
-  if (t.isLiteral(target) || t.isArrayExpression(target) || t.isObjectExpression(target)) {
-    // todo: possibly call some helper that will resolve these to a flow type annotation
-  }
-
   if (t.isCallExpression(target)) {
     // todo: resolve this to a return type
   }
@@ -411,6 +436,28 @@ Scope.prototype.addBindingToFunctionScope = function (node, kind) {
   if (kind) extend(scope.bindingKinds[kind], ids);
 };
 
+/**
+ * Walk up the scope tree and check to see if it has a binding with the provided
+ * name, if it does return the binding identifier and scope.
+ *
+ * @param {String} name
+ * @returns {Object} { binding, scope }
+ */
+
+Scope.prototype.getBindingWithScope = function (name) {
+  var scope = this;
+
+  do {
+    binding = scope.getOwnBinding(name);
+    var if (binding) {
+      return {
+        binding: binding,
+        scope:   scope
+      };
+    }
+  } while (scope = scope.parent);
+};
+
 /**
  * Walk up the scope tree until we hit either a Function or reach the
  * very top and hit Program.