[Routing] Fix the annotation loader taking a class constant as a beginning of a class name

src/Symfony/Component/Routing/Loader/AnnotationFileLoader.php

@@ -96,6 +96,8 @@ class AnnotationFileLoader extends FileLoader
             $token = $tokens[$i];
 
             if (!isset($token[1])) {
+                $class = false;
+
                 continue;
             }
 

src/Symfony/Component/Routing/Tests/Fixtures/AnnotatedClasses/FooTrait.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Symfony\Component\Routing\Tests\Fixtures\AnnotatedClasses;
+
+trait FooTrait
+{
+    public function doBar()
+    {
+        $baz = self::class;
+        if (true) {
+        }
+    }
+}

src/Symfony/Component/Routing/Tests/Loader/AnnotationFileLoaderTest.php

@@ -35,6 +35,16 @@ class AnnotationFileLoaderTest extends AbstractAnnotationLoaderTest
         $this->loader->load(__DIR__.'/../Fixtures/AnnotatedClasses/FooClass.php');
     }
 
+    /**
+     * @requires PHP 5.4
+     */
+    public function testLoadTraitWithClassConstant()
+    {
+        $this->reader->expects($this->never())->method('getClassAnnotation');
+
+        $this->loader->load(__DIR__.'/../Fixtures/AnnotatedClasses/FooTrait.php');
+    }
+
     /**
      * @requires PHP 5.6
      */