Issue #2042545 by tim.plunkett: Fixed Annotation parsing should ignore @file doxygen.

core/lib/Drupal/Component/Plugin/Discovery/AnnotatedClassDiscovery.php

@@ -78,6 +78,7 @@ public function getDefinitions() {
     $reader = new AnnotationReader();
     // Prevent @endlink from being parsed as an annotation.
     $reader->addGlobalIgnoredName('endlink');
+    $reader->addGlobalIgnoredName('file');
 
     // Register the namespaces of classes that can be used for annotations.
     AnnotationRegistry::registerAutoloadNamespaces($this->getAnnotationNamespaces());

core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/plugin_test/fruit/NonAnnotatedClass.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\plugin_test\Plugin\plugin_test\fruit\NonAnnotatedClass.
+ */
+
+namespace Drupal\plugin_test\Plugin\plugin_test\fruit;
+
+class NonAnnotatedClass {}