don't reassign decorated classes - fixes #1167

test/core/fixtures/transformation/es7.decorators/class-modules/actual.js

@@ -0,0 +1,6 @@
+import foo from "foo";
+
+@foo
+export default class Foo {
+
+}

test/core/fixtures/transformation/es7.decorators/class-modules/expected.js

@@ -0,0 +1,21 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+var _foo = require("foo");
+
+var _foo2 = babelHelpers.interopRequireWildcard(_foo);
+
+var Foo = (function () {
+  function Foo() {
+    babelHelpers.classCallCheck(this, Foo);
+  }
+
+  Foo = _foo2["default"](Foo) || Foo;
+  return Foo;
+})();
+
+exports["default"] = Foo;
+module.exports = exports["default"];