dry up array comprehension and arrow functions by introducing an alias-functions transformer

test/fixtures/syntax/array-comprehension/arguments/expected.js

@@ -1,6 +1,6 @@
 function add() {
   var _arguments = arguments;
-  return [1, 2, 3].map(function () {
+  return [1, 2, 3].map(function (i) {
     return i * _arguments[0];
   });
 }

test/fixtures/syntax/array-comprehension/this/expected.js

@@ -1,6 +1,6 @@
 function add() {
   var _this = this;
-  return [1, 2, 3].map(function () {
+  return [1, 2, 3].map(function (i) {
     return i * _this.multiplier;
   });
 }

test/fixtures/syntax/arrow-functions/arguments/actual.js

@@ -32,3 +32,14 @@ function five(obj) {
   return fn();
 }
 five({ arguments: ["foo"] });
+
+function six(obj) {
+  var fn = () => {
+    var fn2 = function () {
+      return arguments[0];
+    };
+    return fn2("foobar");
+  };
+  return fn();
+}
+six();

test/fixtures/syntax/arrow-functions/arguments/expected.js

@@ -43,3 +43,14 @@ function five(obj) {
   return fn();
 }
 five({ arguments: ["foo"] });
+
+function six(obj) {
+  var fn = function () {
+    var fn2 = function () {
+      return arguments[0];
+    };
+    return fn2("foobar");
+  };
+  return fn();
+}
+six();

test/fixtures/syntax/arrow-functions/this/expected.js

@@ -1,3 +1,4 @@
+var _this = this;
 var t = function (x) {
-  return this.x + x;
-}.bind(this);
+  return _this.x + x;
+};