Issue #3491360 by bluegeek9, nikathone: Issues Reported by PHPstan

src/ChartManager.php

@@ -28,6 +28,7 @@ class ChartManager extends DefaultPluginManager {
   public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
     parent::__construct('Plugin/chart/Library', $namespaces, $module_handler, 'Drupal\charts\Plugin\chart\Library\ChartInterface', 'Drupal\charts\Annotation\Chart');
 
+    $this->setCacheBackend($cache_backend, 'chart');
     $this->alterInfo('charts_chart_library');
   }