diff --git a/src/Ajax/SelectEntitiesCommand.php b/src/Ajax/SelectEntitiesCommand.php
index fc95a04..e2af63c 100644
--- a/src/Ajax/SelectEntitiesCommand.php
+++ b/src/Ajax/SelectEntitiesCommand.php
@@ -33,7 +33,7 @@ class SelectEntitiesCommand implements CommandInterface {
    *   Entities that were selected. Each entity is represented with an array
    *   consisting of three values (entity ID, entity UUID and entity type).
    */
-  public function __construct($uuid, $entities) {
+  public function __construct($uuid, array $entities) {
     $this->uuid = $uuid;
     $this->entities = $entities;
   }
diff --git a/src/Events/AlterEntityBrowserDisplayData.php b/src/Events/AlterEntityBrowserDisplayData.php
index 22141bf..befbe7e 100644
--- a/src/Events/AlterEntityBrowserDisplayData.php
+++ b/src/Events/AlterEntityBrowserDisplayData.php
@@ -87,7 +87,7 @@ class AlterEntityBrowserDisplayData extends EventBase {
    * @param array $data
    *   Data array.
    */
-  public function setData($data) {
+  public function setData(array $data) {
     $this->data = $data;
   }
 
diff --git a/src/Events/RegisterJSCallbacks.php b/src/Events/RegisterJSCallbacks.php
index 9431630..1ca3970 100644
--- a/src/Events/RegisterJSCallbacks.php
+++ b/src/Events/RegisterJSCallbacks.php
@@ -40,7 +40,7 @@ class RegisterJSCallbacks extends EventBase {
    * @param array $callbacks
    *   List of callbacks.
    */
-  public function setCallbacks($callbacks) {
+  public function setCallbacks(array $callbacks) {
     $this->callbacks = $callbacks;
   }
 
diff --git a/src/Plugin/views/field/SelectForm.php b/src/Plugin/views/field/SelectForm.php
index d498082..e871c11 100644
--- a/src/Plugin/views/field/SelectForm.php
+++ b/src/Plugin/views/field/SelectForm.php
@@ -57,7 +57,7 @@ class SelectForm extends FieldPluginBase {
    * @param array $render
    *   An associative array containing the structure of the form.
    */
-  public function viewsForm(&$render) {
+  public function viewsForm(array &$render) {
     // Only add the bulk form options and buttons if there are results.
     if (!empty($this->view->result)) {
       // Render checkboxes for all rows.
diff --git a/src/WidgetBase.php b/src/WidgetBase.php
index f5d2ea7..ff75658 100644
--- a/src/WidgetBase.php
+++ b/src/WidgetBase.php
@@ -311,7 +311,7 @@ abstract class WidgetBase extends PluginBase implements WidgetInterface, Contain
    *   A list of constraint violations. If the list is empty, validation
    *   succeeded.
    */
-  protected function runWidgetValidators(array $entities, $validators = []) {
+  protected function runWidgetValidators(array $entities, array $validators = []) {
     $violations = new ConstraintViolationList();
     foreach ($validators as $validator_id => $options) {
       /** @var \Drupal\entity_browser\WidgetValidationInterface $widget_validator */
@@ -365,7 +365,7 @@ abstract class WidgetBase extends PluginBase implements WidgetInterface, Contain
    * @param array $widget_context
    *   The widget context.
    */
-  protected function handleWidgetContext($widget_context) {
+  protected function handleWidgetContext(array $widget_context) {
     foreach ($this->defaultConfiguration() as $key => $value) {
       if (isset($widget_context[$key]) && isset($this->configuration[$key])) {
         $this->configuration[$key] = $widget_context[$key];