diff --git a/entity_hierarchy.drush.inc b/entity_hierarchy.drush.inc
index 824987aee50dcccb9bb18fa235a24a6fa6dc38bb..a7b54f8542790ee5b4e68ac5aa07c634e074792e 100644
--- a/entity_hierarchy.drush.inc
+++ b/entity_hierarchy.drush.inc
@@ -9,19 +9,19 @@
  * Implements hook_drush_command().
  */
 function entity_hierarchy_drush_command() {
-  $items = array();
+  $items = [];
 
-  $items['entity-hierarchy-rebuild-tree'] = array(
+  $items['entity-hierarchy-rebuild-tree'] = [
     'description' => 'Rebuild tree.',
-    'arguments' => array(
+    'arguments' => [
       'field_name' => dt('Field machine name'),
       'entity_type_id' => dt('Entity type id'),
-    ),
-    'options' => array(),
-    'examples' => array(
+    ],
+    'options' => [],
+    'examples' => [
       'drush entity-hierarchy-rebuild-tree field_parents node' => 'Rebuild tree for node field named field_parents.',
-    ),
-  );
+    ],
+  ];
   return $items;
 }
 
diff --git a/modules/entity_hierarchy_breadcrumb/src/HierarchyBasedBreadcrumbBuilder.php b/modules/entity_hierarchy_breadcrumb/src/HierarchyBasedBreadcrumbBuilder.php
index d358e6c6eca08a5ca33c9c380e52690ed18597b3..296d406c65ce4129fad70feef28e4764a5ab75d4 100644
--- a/modules/entity_hierarchy_breadcrumb/src/HierarchyBasedBreadcrumbBuilder.php
+++ b/modules/entity_hierarchy_breadcrumb/src/HierarchyBasedBreadcrumbBuilder.php
@@ -102,7 +102,7 @@ class HierarchyBasedBreadcrumbBuilder implements BreadcrumbBuilderInterface {
    */
   public function build(RouteMatchInterface $route_match) {
     $breadcrumb = new Breadcrumb();
-    /** @var ContentEntityInterface $route_entity */
+    /** @var \Drupal\Core\Entity\ContentEntityInterface $route_entity */
     $route_entity = $this->getEntityFromRouteMatch($route_match);
     $breadcrumb->addCacheableDependency($route_match->getRouteObject());
 
diff --git a/modules/entity_hierarchy_workbench_access/src/Plugin/Validation/Constraint/ValidEntityHierarchySection.php b/modules/entity_hierarchy_workbench_access/src/Plugin/Validation/Constraint/ValidEntityHierarchySection.php
index a6ecc224581d680c33339d56920625e543454013..e2acb8d5d6aad2cd89ff8840280611312483940c 100644
--- a/modules/entity_hierarchy_workbench_access/src/Plugin/Validation/Constraint/ValidEntityHierarchySection.php
+++ b/modules/entity_hierarchy_workbench_access/src/Plugin/Validation/Constraint/ValidEntityHierarchySection.php
@@ -12,7 +12,6 @@ use Symfony\Component\Validator\ExecutionContextInterface;
  * @Constraint(
  *   id = "ValidHierarchySection",
  *   label = @Translation("Valid hierarchy selection", context = "Validation"),
- *   type = "entity:comment"
  * )
  */
 class ValidEntityHierarchySection extends Constraint implements ConstraintValidatorInterface {
diff --git a/src/Plugin/EntityReferenceSelection/EntityHierarchy.php b/src/Plugin/EntityReferenceSelection/EntityHierarchy.php
index d8f560f9297af06926b07ea53f8c094476f916c4..ac2f2bc0c0637445457b4567eaff85f24e897504 100644
--- a/src/Plugin/EntityReferenceSelection/EntityHierarchy.php
+++ b/src/Plugin/EntityReferenceSelection/EntityHierarchy.php
@@ -110,10 +110,10 @@ class EntityHierarchy extends DefaultSelection {
     $result = $query->execute();
 
     if (empty($result)) {
-      return array();
+      return [];
     }
 
-    $options = array();
+    $options = [];
     $entities = $this->entityManager->getStorage($target_type)->loadMultiple($result);
 
     // We assume target and definition are one and the same, as there is no
diff --git a/src/Plugin/Field/FieldFormatter/EntityReferenceHierarchyLabelFormatter.php b/src/Plugin/Field/FieldFormatter/EntityReferenceHierarchyLabelFormatter.php
index 0e6ee8d365fe701d49fcec28fd2dd955700e6610..510aeb6fd82911f72b10dd3029ea931c9cbeac6a 100644
--- a/src/Plugin/Field/FieldFormatter/EntityReferenceHierarchyLabelFormatter.php
+++ b/src/Plugin/Field/FieldFormatter/EntityReferenceHierarchyLabelFormatter.php
@@ -25,7 +25,7 @@ class EntityReferenceHierarchyLabelFormatter extends EntityReferenceLabelFormatt
    */
   public function settingsForm(array $form, FormStateInterface $form_state) {
     $elements = parent::settingsForm($form, $form_state);
-    $elements['weight_output'] = array(
+    $elements['weight_output'] = [
       '#type' => 'radios',
       '#options' => [
         'suffix' => t('After title'),
@@ -34,7 +34,7 @@ class EntityReferenceHierarchyLabelFormatter extends EntityReferenceLabelFormatt
       '#title' => t('Output weigh'),
       '#default_value' => $this->getSetting('weight_output'),
       '#required' => TRUE,
-    );
+    ];
 
     return $elements;
   }
@@ -54,7 +54,7 @@ class EntityReferenceHierarchyLabelFormatter extends EntityReferenceLabelFormatt
         $action = t('suffix after title');
         break;
     }
-    $summary[] = t('Show weight as @action', array('@action' => $action));
+    $summary[] = t('Show weight as @action', ['@action' => $action]);
 
     return $summary;
   }
diff --git a/src/Plugin/Field/FieldType/EntityReferenceHierarchy.php b/src/Plugin/Field/FieldType/EntityReferenceHierarchy.php
index 8f3facf8995b1cd2bbb8df1200f1be1a71e93c60..0598bbea8b4dc6c61eff4f97a8b310ed5a1c978e 100644
--- a/src/Plugin/Field/FieldType/EntityReferenceHierarchy.php
+++ b/src/Plugin/Field/FieldType/EntityReferenceHierarchy.php
@@ -54,10 +54,10 @@ class EntityReferenceHierarchy extends EntityReferenceItem {
    */
   public static function schema(FieldStorageDefinitionInterface $field_definition) {
     $schema = parent::schema($field_definition);
-    $schema['columns']['weight'] = array(
+    $schema['columns']['weight'] = [
       'type' => 'int',
       'unsigned' => FALSE,
-    );
+    ];
     return $schema;
   }
 
@@ -65,11 +65,11 @@ class EntityReferenceHierarchy extends EntityReferenceItem {
    * {@inheritdoc}
    */
   public static function defaultFieldSettings() {
-    return array(
+    return [
       'weight_label' => t('Weight'),
       'weight_min' => self::HIERARCHY_MIN_CHILD_WEIGHT,
       'weight_max' => self::HIERARCHY_MAX_CHILD_WEIGHT,
-    ) + parent::defaultFieldSettings();
+    ] + parent::defaultFieldSettings();
   }
 
   /**
@@ -106,7 +106,7 @@ class EntityReferenceHierarchy extends EntityReferenceItem {
     // list of field-types with options for each destination entity type.
     // Too much work, we'll just make people fill that out later.
     // Also, keeps the field type dropdown from getting too cluttered.
-    return array();
+    return [];
   }
 
   /**
diff --git a/src/Plugin/Field/FieldWidget/EntityReferenceHierarchySelect.php b/src/Plugin/Field/FieldWidget/EntityReferenceHierarchySelect.php
index 8eed6627d33a9aa45a354a5f7dd8d907024bace9..c095b10595d6131552b28e975bf799073bd8d635 100644
--- a/src/Plugin/Field/FieldWidget/EntityReferenceHierarchySelect.php
+++ b/src/Plugin/Field/FieldWidget/EntityReferenceHierarchySelect.php
@@ -26,24 +26,24 @@ class EntityReferenceHierarchySelect extends OptionsWidgetBase {
    */
   public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
     $element = parent::formElement($items, $delta, $element, $form, $form_state);
-    $element += array(
+    $element += [
       '#type' => 'select',
       '#options' => $this->getOptions($items->getEntity()),
       '#default_value' => isset($items[$delta]->target_id) ? $items[$delta]->target_id : '',
-    );
+    ];
 
-    $widget = array(
+    $widget = [
       '#attributes' => ['class' => ['form--inline', 'clearfix']],
       '#theme_wrappers' => ['container'],
-    );
+    ];
 
     $widget['target_id'] = $element;
-    $widget['weight'] = array(
+    $widget['weight'] = [
       '#type' => 'number',
       '#size' => '4',
       '#default_value' => isset($items[$delta]) ? $items[$delta]->weight : 1,
       '#weight' => 10,
-    );
+    ];
     kint($widget);
 
     if ($this->fieldDefinition->getFieldStorageDefinition()->isMultiple()) {
@@ -92,7 +92,7 @@ class EntityReferenceHierarchySelect extends OptionsWidgetBase {
   public static function validateElement(array $element, FormStateInterface $form_state) {
     if ($element['#value'] == '_none') {
       if ($element['#required'] && $element['#value'] == '_none') {
-        $form_state->setError($element, t('@name field is required.', array('@name' => $element['#title'])));
+        $form_state->setError($element, t('@name field is required.', ['@name' => $element['#title']]));
       }
       else {
         $form_state->setValueForElement($element, NULL);
diff --git a/src/Plugin/views/argument/HierarchyIsChildOfEntity.php b/src/Plugin/views/argument/HierarchyIsChildOfEntity.php
index e85a4bfb5944ec919c6de87302ef175fecaea8d5..b1ab80ef0bc9cd13864b3bf31c818e9181f13c2f 100644
--- a/src/Plugin/views/argument/HierarchyIsChildOfEntity.php
+++ b/src/Plugin/views/argument/HierarchyIsChildOfEntity.php
@@ -64,6 +64,8 @@ class HierarchyIsChildOfEntity extends ArgumentPluginBase {
    *   Entity type manager.
    * @param \Drupal\entity_hierarchy\Storage\NestedSetNodeKeyFactory $nodeKeyFactory
    *   Node key factory.
+   * @param \Drupal\Core\Database\Connection $database
+   *   Database connection.
    */
   public function __construct(array $configuration, $plugin_id, $plugin_definition, NestedSetStorageFactory $nestedSetStorageFactory, EntityTypeManagerInterface $entityTypeManager, NestedSetNodeKeyFactory $nodeKeyFactory, Connection $database) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
@@ -167,7 +169,7 @@ class HierarchyIsChildOfEntity extends ArgumentPluginBase {
     $options = parent::defineOptions();
 
     // Allow filtering depth as well.
-    $options['depth'] = array('default' => 0);
+    $options['depth'] = ['default' => 0];
 
     return $options;
   }
diff --git a/tests/src/Functional/HideWeightFieldFunctionalTest.php b/tests/src/Functional/HideWeightFieldFunctionalTest.php
index c90852d4a21ff01ee65348efd10cbe328ba234d6..a636abc68bc95552e6c96751fc218b6e570ab15f 100644
--- a/tests/src/Functional/HideWeightFieldFunctionalTest.php
+++ b/tests/src/Functional/HideWeightFieldFunctionalTest.php
@@ -39,10 +39,10 @@ class HideWeightFieldFunctionalTest extends BrowserTestBase {
     $this->setupEntityHierarchyField(static::ENTITY_TYPE, static::ENTITY_TYPE, static::FIELD_NAME);
     $this->additionalSetup();
     $this->getEntityFormDisplay(self::ENTITY_TYPE, self::ENTITY_TYPE, 'default')
-      ->setComponent(self::FIELD_NAME, array(
+      ->setComponent(self::FIELD_NAME, [
         'type' => 'entity_reference_hierarchy_autocomplete',
         'weight' => 20,
-      ))
+      ])
       ->save();
   }