Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/phpunit/phpunit-mock-objects/tests/_fixture/SomeClass.php

@@ -0,0 +1,13 @@
+<?php
+class SomeClass
+{
+    public function doSomething($a, $b)
+    {
+        return null;
+    }
+
+    public function doSomethingElse($c)
+    {
+        return null;
+    }
+}