Merge pull request #3138 from loganfsmyth/class-rename-failure-T2494

Skip name inference on hard-to-replace classes - fixes T2494

packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/T2494/actual.js

@@ -0,0 +1,3 @@
+var x = {
+  Foo: class extends Foo {}
+};

packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/T2494/expected.js

@@ -0,0 +1,14 @@
+"use strict";
+
+var x = {
+  Foo: (function (_Foo) {
+    babelHelpers.inherits(_class, _Foo);
+
+    function _class() {
+      babelHelpers.classCallCheck(this, _class);
+      return babelHelpers.possibleConstructorReturn(this, Object.getPrototypeOf(_class).apply(this, arguments));
+    }
+
+    return _class;
+  })(Foo)
+};