Merge pull request #3383 from babel/T7160

Regression with exporting an arrow function with a default param

packages/babel-plugin-transform-es2015-modules-commonjs/test/fixtures/regression/T7160/actual.js

@@ -0,0 +1,7 @@
+export var foo = function(gen, ctx = null) {
+
+}
+
+export var bar = (gen, ctx = null) => {
+
+}

packages/babel-plugin-transform-es2015-modules-commonjs/test/fixtures/regression/T7160/expected.js

@@ -0,0 +1,12 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+var foo = exports.foo = function foo(gen) {
+  var ctx = arguments.length <= 1 || arguments[1] === undefined ? null : arguments[1];
+};
+
+var bar = exports.bar = function bar(gen) {
+  var ctx = arguments.length <= 1 || arguments[1] === undefined ? null : arguments[1];
+};

packages/babel-plugin-transform-es2015-modules-commonjs/test/fixtures/regression/T7160/options.json

@@ -0,0 +1,3 @@
+{
+  "presets": ["es2015"]
+}