diff --git a/core/lib/Drupal/Core/Template/TwigExtension.php b/core/lib/Drupal/Core/Template/TwigExtension.php
index 75ea035..8988fc8 100644
--- a/core/lib/Drupal/Core/Template/TwigExtension.php
+++ b/core/lib/Drupal/Core/Template/TwigExtension.php
@@ -15,9 +15,9 @@
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\Routing\UrlGeneratorInterface;
+use Drupal\Core\Theme\ThemeManagerInterface;
 use Drupal\Core\Url;
 use Drupal\Core\Utility\LinkGeneratorInterface;
-use Drupal\Core\Theme\ThemeManagerInterface;
 
 /**
  * A class providing Drupal Twig extensions.
@@ -102,7 +102,7 @@ public function setThemeManager(ThemeManagerInterface $theme_manager) {
    * {@inheritdoc}
    */
   public function getFunctions() {
-    return array(
+    return [
       // This function will receive a renderable array, if an array is detected.
       new \Twig_SimpleFunction('render_var', array($this, 'renderVar')),
       // The url and path function are defined in close parallel to those found
@@ -113,8 +113,8 @@ public function getFunctions() {
       new \Twig_SimpleFunction('link', array($this, 'getLink')),
       new \Twig_SimpleFunction('file_url', 'file_create_url'),
       new \Twig_SimpleFunction('attach_library', array($this, 'attachLibrary')),
-      new \Twig_SimpleFunction('active_theme', array($this, 'activeTheme')),
-    );
+      new \Twig_SimpleFunction('active_theme', [$this, 'activeTheme']),
+    ];
   }
 
   /**
diff --git a/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php b/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php
index fe5d49f..970741b 100644
--- a/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php
+++ b/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php
@@ -88,7 +88,7 @@ public function registryLoaderRender() {
    * Menu callback for testing the active theme function.
    */
   public function activeThemeRender() {
-    return array('#theme' => 'twig_theme_test_active_theme');
+    return ['#theme' => 'twig_theme_test_active_theme'];
   }
 
 }
diff --git a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module
index dda6528..7867531 100644
--- a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module
+++ b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module
@@ -54,10 +54,10 @@ function twig_theme_test_theme($existing, $type, $theme, $path) {
     'variables' => array(),
     'template' => 'twig_theme_test.attach_library',
   );
-  $items['twig_theme_test_active_theme'] = array(
-    'variables' => array(),
+  $items['twig_theme_test_active_theme'] = [
+    'variables' => [],
     'template' => 'twig_theme_test.active_theme',
-  );
+  ];
   return $items;
 }