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

vendor/symfony/class-loader/Tests/Fixtures/php5.4/traits.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace {
+    trait TFoo
+    {
+    }
+
+    class CFoo
+    {
+        use TFoo;
+    }
+}
+
+namespace Foo {
+    trait TBar
+    {
+    }
+
+    interface IBar
+    {
+    }
+
+    trait TFooBar
+    {
+    }
+
+    class CBar implements IBar
+    {
+        use TBar;
+        use TFooBar;
+    }
+}