diff --git a/src/babel/transformation/file/index.js b/src/babel/transformation/file/index.js
index ed2ea6d4f8..eaa53be048 100644
--- a/src/babel/transformation/file/index.js
+++ b/src/babel/transformation/file/index.js
@@ -44,6 +44,7 @@ export default class File {
     this.usedHelpers = {};
     this.dynamicData = {};
     this.data        = {};
+    this.uids        = {};
 
     this.lastStatements = [];
     this.log            = new Logger(this, opts.filename || "unknown");
diff --git a/src/babel/traversal/scope.js b/src/babel/traversal/scope.js
index e090462403..99056e5bab 100644
--- a/src/babel/traversal/scope.js
+++ b/src/babel/traversal/scope.js
@@ -135,7 +135,7 @@ export default class Scope {
       uid = this._generateUid(name, i);
       i++;
     } while (this.hasBinding(uid) || this.hasGlobal(uid) || this.hasUid(uid));
-    this.getFunctionParent().uids[uid] = true;
+    this.file.uids[uid] = true;
     return uid;
   }
 
@@ -152,7 +152,7 @@ export default class Scope {
   hasUid(name): boolean {
     var scope = this;
     do {
-      if (scope.uids[name]) return true;
+      if (scope.file.uids[name]) return true;
       scope = scope.parent;
     } while (scope);
     return false;
@@ -434,8 +434,7 @@ export default class Scope {
 
     info = this.block._scopeInfo = {
       bindings: object(),
-      globals:  object(),
-      uids:     object()
+      globals:  object()
     };
 
     extend(this, info);
@@ -658,7 +657,7 @@ export default class Scope {
     if (!name) return false;
     if (this.hasOwnBinding(name)) return true;
     if (this.parentHasBinding(name)) return true;
-    if (this.uids[name]) return true;
+    if (this.file.uids[name]) return true;
     if (includes(Scope.globals, name)) return true;
     if (includes(Scope.contextVariables, name)) return true;
     return false;
diff --git a/test/core/fixtures/transformation/es6.arrow-functions/arguments/expected.js b/test/core/fixtures/transformation/es6.arrow-functions/arguments/expected.js
index eac62b4a0e..b8104fab4d 100644
--- a/test/core/fixtures/transformation/es6.arrow-functions/arguments/expected.js
+++ b/test/core/fixtures/transformation/es6.arrow-functions/arguments/expected.js
@@ -11,17 +11,17 @@ function one() {
 one(1, 2);
 
 function two() {
-  var _arguments = arguments;
+  var _arguments2 = arguments;
 
   var inner = function inner() {
-    return _arguments;
+    return _arguments2;
   };
 
   var another = function another() {
-    var _arguments2 = arguments;
+    var _arguments3 = arguments;
 
     var inner2 = function inner2() {
-      return _arguments2;
+      return _arguments3;
     };
   };
 
@@ -30,20 +30,20 @@ function two() {
 two(1, 2);
 
 function three() {
-  var _arguments = arguments;
+  var _arguments4 = arguments;
 
   var fn = function fn() {
-    return _arguments[0] + "bar";
+    return _arguments4[0] + "bar";
   };
   return fn();
 }
 three("foo");
 
 function four() {
-  var _arguments = arguments;
+  var _arguments5 = arguments;
 
   var fn = function fn() {
-    return _arguments[0].foo + "bar";
+    return _arguments5[0].foo + "bar";
   };
   return fn();
 }
@@ -66,4 +66,4 @@ function six(obj) {
   };
   return fn();
 }
-six();
+six();
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/es6.block-scoping/for-break-continue-return/expected.js b/test/core/fixtures/transformation/es6.block-scoping/for-break-continue-return/expected.js
index 57da26353c..b67076795a 100644
--- a/test/core/fixtures/transformation/es6.block-scoping/for-break-continue-return/expected.js
+++ b/test/core/fixtures/transformation/es6.block-scoping/for-break-continue-return/expected.js
@@ -16,7 +16,7 @@
     }
   };
 
-  _loop: for (var i in nums) {
+  _loop2: for (var i in nums) {
     var _ret = _loop(i);
 
     switch (_ret) {
@@ -24,7 +24,7 @@
         continue;
 
       case "break":
-        break _loop;
+        break _loop2;
 
       default:
         if (typeof _ret === "object") return _ret.v;
diff --git a/test/core/fixtures/transformation/es6.classes-loose/accessing-super-class/expected.js b/test/core/fixtures/transformation/es6.classes-loose/accessing-super-class/expected.js
index 60f3c20e81..fa1b8ef7ae 100644
--- a/test/core/fixtures/transformation/es6.classes-loose/accessing-super-class/expected.js
+++ b/test/core/fixtures/transformation/es6.classes-loose/accessing-super-class/expected.js
@@ -20,11 +20,11 @@ var Test = (function (_Foo) {
   babelHelpers.inherits(Test, _Foo);
 
   Test.prototype.test = function test() {
-    var _Foo$prototype$test, _Foo$prototype$test2;
+    var _Foo$prototype$test3, _Foo$prototype$test4;
 
     _Foo.prototype.test.call(this);
-    (_Foo$prototype$test = _Foo.prototype.test).call.apply(_Foo$prototype$test, [this].concat(babelHelpers.slice.call(arguments)));
-    (_Foo$prototype$test2 = _Foo.prototype.test).call.apply(_Foo$prototype$test2, [this, "test"].concat(babelHelpers.slice.call(arguments)));
+    (_Foo$prototype$test3 = _Foo.prototype.test).call.apply(_Foo$prototype$test3, [this].concat(babelHelpers.slice.call(arguments)));
+    (_Foo$prototype$test4 = _Foo.prototype.test).call.apply(_Foo$prototype$test4, [this, "test"].concat(babelHelpers.slice.call(arguments)));
   };
 
   Test.foo = function foo() {
diff --git a/test/core/fixtures/transformation/es6.classes/accessing-super-class/expected.js b/test/core/fixtures/transformation/es6.classes/accessing-super-class/expected.js
index ea5b6257f4..42672ea451 100644
--- a/test/core/fixtures/transformation/es6.classes/accessing-super-class/expected.js
+++ b/test/core/fixtures/transformation/es6.classes/accessing-super-class/expected.js
@@ -21,21 +21,21 @@ var Test = (function (_Foo) {
   babelHelpers.createClass(Test, [{
     key: "test",
     value: function test() {
-      var _babelHelpers$get;
+      var _babelHelpers$get3;
 
       babelHelpers.get(Object.getPrototypeOf(Test.prototype), "test", this).call(this);
       babelHelpers.get(Object.getPrototypeOf(Test.prototype), "test", this).apply(this, arguments);
-      (_babelHelpers$get = babelHelpers.get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_babelHelpers$get, [this, "test"].concat(babelHelpers.slice.call(arguments)));
+      (_babelHelpers$get3 = babelHelpers.get(Object.getPrototypeOf(Test.prototype), "test", this)).call.apply(_babelHelpers$get3, [this, "test"].concat(babelHelpers.slice.call(arguments)));
     }
   }], [{
     key: "foo",
     value: function foo() {
-      var _babelHelpers$get;
+      var _babelHelpers$get4;
 
       babelHelpers.get(Object.getPrototypeOf(Test), "foo", this).call(this);
       babelHelpers.get(Object.getPrototypeOf(Test), "foo", this).apply(this, arguments);
-      (_babelHelpers$get = babelHelpers.get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_babelHelpers$get, [this, "test"].concat(babelHelpers.slice.call(arguments)));
+      (_babelHelpers$get4 = babelHelpers.get(Object.getPrototypeOf(Test), "foo", this)).call.apply(_babelHelpers$get4, [this, "test"].concat(babelHelpers.slice.call(arguments)));
     }
   }]);
   return Test;
-})(Foo);
+})(Foo);
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/es6.destructuring/parameters/expected.js b/test/core/fixtures/transformation/es6.destructuring/parameters/expected.js
index d88a23e959..50365469a1 100644
--- a/test/core/fixtures/transformation/es6.destructuring/parameters/expected.js
+++ b/test/core/fixtures/transformation/es6.destructuring/parameters/expected.js
@@ -9,29 +9,29 @@ function somethingAdvanced(_ref) {
   var y2 = _ref$bottomRight.y;
 }
 
-function unpackObject(_ref) {
-  var title = _ref.title;
-  var author = _ref.author;
+function unpackObject(_ref2) {
+  var title = _ref2.title;
+  var author = _ref2.author;
 
   return title + " " + author;
 }
 
 console.log(unpackObject({ title: "title", author: "author" }));
 
-var unpackArray = function unpackArray(_ref, _ref3) {
-  var _ref2 = babelHelpers.slicedToArray(_ref, 3);
-
-  var a = _ref2[0];
-  var b = _ref2[1];
-  var c = _ref2[2];
-
+var unpackArray = function unpackArray(_ref3, _ref4) {
   var _ref32 = babelHelpers.slicedToArray(_ref3, 3);
 
-  var x = _ref32[0];
-  var y = _ref32[1];
-  var z = _ref32[2];
+  var a = _ref32[0];
+  var b = _ref32[1];
+  var c = _ref32[2];
+
+  var _ref42 = babelHelpers.slicedToArray(_ref4, 3);
+
+  var x = _ref42[0];
+  var y = _ref42[1];
+  var z = _ref42[2];
 
   return a + b + c;
 };
 
-console.log(unpackArray(["hello", ", ", "world"], [1, 2, 3]));
+console.log(unpackArray(["hello", ", ", "world"], [1, 2, 3]));
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/es6.parameters.rest/deopt/expected.js b/test/core/fixtures/transformation/es6.parameters.rest/deopt/expected.js
index fff7c33680..eeef013489 100644
--- a/test/core/fixtures/transformation/es6.parameters.rest/deopt/expected.js
+++ b/test/core/fixtures/transformation/es6.parameters.rest/deopt/expected.js
@@ -9,8 +9,8 @@ var x = function x(foo) {
 };
 
 var y = function y(foo) {
-  for (var _len = arguments.length, bar = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
-    bar[_key - 1] = arguments[_key];
+  for (var _len2 = arguments.length, bar = Array(_len2 > 1 ? _len2 - 1 : 0), _key2 = 1; _key2 < _len2; _key2++) {
+    bar[_key2 - 1] = arguments[_key2];
   }
 
   var x = function z(bar) {
@@ -19,8 +19,8 @@ var y = function y(foo) {
 };
 
 var b = function b(x, y) {
-  for (var _len = arguments.length, args = Array(_len > 2 ? _len - 2 : 0), _key = 2; _key < _len; _key++) {
-    args[_key - 2] = arguments[_key];
+  for (var _len3 = arguments.length, args = Array(_len3 > 2 ? _len3 - 2 : 0), _key3 = 2; _key3 < _len3; _key3++) {
+    args[_key3 - 2] = arguments[_key3];
   }
 
   console.log(args[0]);
@@ -29,8 +29,8 @@ var b = function b(x, y) {
 };
 
 var z = function z(foo) {
-  for (var _len = arguments.length, bar = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
-    bar[_key - 1] = arguments[_key];
+  for (var _len4 = arguments.length, bar = Array(_len4 > 1 ? _len4 - 1 : 0), _key4 = 1; _key4 < _len4; _key4++) {
+    bar[_key4 - 1] = arguments[_key4];
   }
 
   var x = function x() {
@@ -39,18 +39,18 @@ var z = function z(foo) {
 };
 
 var a = function a(foo) {
-  for (var _len = arguments.length, bar = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
-    bar[_key - 1] = arguments[_key];
+  for (var _len5 = arguments.length, bar = Array(_len5 > 1 ? _len5 - 1 : 0), _key5 = 1; _key5 < _len5; _key5++) {
+    bar[_key5 - 1] = arguments[_key5];
   }
 
   return bar.join(",");
 };
 
 var b = function b(foo) {
-  for (var _len = arguments.length, bar = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
-    bar[_key - 1] = arguments[_key];
+  for (var _len6 = arguments.length, bar = Array(_len6 > 1 ? _len6 - 1 : 0), _key6 = 1; _key6 < _len6; _key6++) {
+    bar[_key6 - 1] = arguments[_key6];
   }
 
   var join = "join";
   return bar[join];
-};
+};
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/es6.tail-call/try-catch/expected.js b/test/core/fixtures/transformation/es6.tail-call/try-catch/expected.js
index 5fbeb6cd4c..c3f3b9bc69 100755
--- a/test/core/fixtures/transformation/es6.tail-call/try-catch/expected.js
+++ b/test/core/fixtures/transformation/es6.tail-call/try-catch/expected.js
@@ -43,21 +43,21 @@
   } finally {}
 })(1000000) === "foo";
 
-(function f(_x) {
-  var _again = true;
+(function f(_x2) {
+  var _again2 = true;
 
-  _function: while (_again) {
-    _again = false;
-    var n = _x;
+  _function2: while (_again2) {
+    _again2 = false;
+    var n = _x2;
 
     if (n <= 0) {
       return "foo";
     }
 
     try {} finally {
-      _x = n - 1;
-      _again = true;
-      continue _function;
+      _x2 = n - 1;
+      _again2 = true;
+      continue _function2;
     }
   }
 })(1000000) === "foo";
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/optimisation.react.constant-elements/function-parameter/expected.js b/test/core/fixtures/transformation/optimisation.react.constant-elements/function-parameter/expected.js
index 6f4e3c43ec..73d39be764 100644
--- a/test/core/fixtures/transformation/optimisation.react.constant-elements/function-parameter/expected.js
+++ b/test/core/fixtures/transformation/optimisation.react.constant-elements/function-parameter/expected.js
@@ -11,9 +11,9 @@ function render(text) {
 var Foo2 = require("Foo");
 
 function createComponent(text) {
-  var _ref = <Foo2>{text}</Foo2>;
+  var _ref2 = <Foo2>{text}</Foo2>;
 
   return function render() {
-    return _ref;
+    return _ref2;
   };
 }
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/optimisation.react.constant-elements/html-element/expected.js b/test/core/fixtures/transformation/optimisation.react.constant-elements/html-element/expected.js
index 1558b57492..54997be255 100644
--- a/test/core/fixtures/transformation/optimisation.react.constant-elements/html-element/expected.js
+++ b/test/core/fixtures/transformation/optimisation.react.constant-elements/html-element/expected.js
@@ -6,8 +6,8 @@ function render() {
   return _ref;
 }
 
-var _ref = <div className="foo"><input type="checkbox" checked={true} /></div>;
+var _ref2 = <div className="foo"><input type="checkbox" checked={true} /></div>;
 
 function render() {
-  return _ref;
+  return _ref2;
 }
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/optimisation.react.constant-elements/inline-elements/expected.js b/test/core/fixtures/transformation/optimisation.react.constant-elements/inline-elements/expected.js
index ac644db0c1..9c2f6fec0d 100644
--- a/test/core/fixtures/transformation/optimisation.react.constant-elements/inline-elements/expected.js
+++ b/test/core/fixtures/transformation/optimisation.react.constant-elements/inline-elements/expected.js
@@ -12,7 +12,7 @@ function render() {
 
 function render() {
   var text = getText();
-  var _ref = {
+  var _ref2 = {
     type: "foo",
     ref: null,
     props: {
@@ -21,6 +21,6 @@ function render() {
     key: null
   };
   return function () {
-    return _ref;
+    return _ref2;
   };
-}
+}
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/react/arrow-functions/expected.js b/test/core/fixtures/transformation/react/arrow-functions/expected.js
index 62f1a66163..eca0547917 100644
--- a/test/core/fixtures/transformation/react/arrow-functions/expected.js
+++ b/test/core/fixtures/transformation/react/arrow-functions/expected.js
@@ -7,9 +7,9 @@ var foo = function foo() {
 };
 
 var bar = function bar() {
-  var _this = this;
+  var _this2 = this;
 
   return function () {
-    return React.createElement(_this.foo, null);
+    return React.createElement(_this2.foo, null);
   };
-};
+};
\ No newline at end of file
diff --git a/test/core/fixtures/transformation/spec.function-name/own-bindings/expected.js b/test/core/fixtures/transformation/spec.function-name/own-bindings/expected.js
index a6346f4707..06312d473d 100644
--- a/test/core/fixtures/transformation/spec.function-name/own-bindings/expected.js
+++ b/test/core/fixtures/transformation/spec.function-name/own-bindings/expected.js
@@ -17,9 +17,9 @@ var f = (function (_f) {
 })(function (f) {});
 
 var obj = {
-  f: (function (_f) {
-    function f(_x) {
-      return _f.apply(this, arguments);
+  f: (function (_f2) {
+    function f(_x2) {
+      return _f2.apply(this, arguments);
     }
 
     f.toString = function () {