.../Field/Plugin/Field/FieldFormatter/EntityReferenceFormatterBase.php  | 2 +-
 .../image/src/Plugin/Field/FieldFormatter/ImageFormatterBase.php        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceFormatterBase.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceFormatterBase.php
index 8c843ff..da534f9 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceFormatterBase.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/EntityReferenceFormatterBase.php
@@ -41,7 +41,7 @@
    *
    * @see ::prepareView()
    */
-  protected function getEntitiesToView(EntityReferenceFieldItemListInterface &$items) {
+  protected function getEntitiesToView(EntityReferenceFieldItemListInterface $items) {
     $entities = array();
 
     $parent_entity_langcode = $items->getEntity()->language()->getId();
diff --git a/core/modules/image/src/Plugin/Field/FieldFormatter/ImageFormatterBase.php b/core/modules/image/src/Plugin/Field/FieldFormatter/ImageFormatterBase.php
index 076b9d4..dd8348e 100644
--- a/core/modules/image/src/Plugin/Field/FieldFormatter/ImageFormatterBase.php
+++ b/core/modules/image/src/Plugin/Field/FieldFormatter/ImageFormatterBase.php
@@ -19,7 +19,7 @@
   /**
    * {@inheritdoc}
    */
-  protected function getEntitiesToView(EntityReferenceFieldItemListInterface &$items) {
+  protected function getEntitiesToView(EntityReferenceFieldItemListInterface $items) {
     // Add the default image if needed.
     if ($items->isEmpty()) {
       $default_image = $this->getFieldSetting('default_image');