diff --git a/core/modules/book/src/Form/BookAdminEditForm.php b/core/modules/book/src/Form/BookAdminEditForm.php
index 2cf7a18..19659df 100644
--- a/core/modules/book/src/Form/BookAdminEditForm.php
+++ b/core/modules/book/src/Form/BookAdminEditForm.php
@@ -71,7 +71,7 @@ public function getFormId() {
    */
   public function buildForm(array $form, FormStateInterface $form_state, NodeInterface $node = NULL) {
     $form['#title'] = $node->label();
-    $form['#node'] = $node;
+    $form_state->set('entity', $node);
     $this->bookAdminTable($node, $form);
     $form['save'] = array(
       '#type' => 'submit',
@@ -128,7 +128,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
       }
     }
 
-    drupal_set_message($this->t('Updated book %title.', array('%title' => $form['#node']->label())));
+    drupal_set_message($this->t('Updated book %title.', array('%title' => $form_state->get('entity')->label())));
   }
 
   /**
diff --git a/core/modules/field_ui/src/Form/FieldEditForm.php b/core/modules/field_ui/src/Form/FieldEditForm.php
index 9e23ee1..5ac901c 100644
--- a/core/modules/field_ui/src/Form/FieldEditForm.php
+++ b/core/modules/field_ui/src/Form/FieldEditForm.php
@@ -84,8 +84,8 @@ public function buildForm(array $form, FormStateInterface $form_state, FieldConf
     $form['#field'] = $field_storage;
     // Create an arbitrary entity object (used by the 'default value' widget).
     $ids = (object) array('entity_type' => $this->field->entity_type, 'bundle' => $this->field->bundle, 'entity_id' => NULL);
-    $form['#entity'] = _field_create_entity_from_ids($ids);
-    $items = $form['#entity']->get($this->field->getName());
+    $form_state->set('entity', _field_create_entity_from_ids($ids));
+    $items = $form_state->get('entity')->get($this->field->getName());
 
     if (!empty($field_storage->locked)) {
       $form['locked'] = array(
@@ -175,7 +175,7 @@ public function buildForm(array $form, FormStateInterface $form_state, FieldConf
    */
   public function validateForm(array &$form, FormStateInterface $form_state) {
     if (isset($form['field']['default_value'])) {
-      $items = $form['#entity']->get($this->field->getName());
+      $items = $form_state->get('entity')->get($this->field->getName());
       $items->defaultValuesFormValidate($form['field']['default_value'], $form, $form_state);
     }
   }
@@ -187,7 +187,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
     // Handle the default value.
     $default_value = array();
     if (isset($form['field']['default_value'])) {
-      $items = $form['#entity']->get($this->field->getName());
+      $items = $form_state->get('entity')->get($this->field->getName());
       $default_value = $items->defaultValuesFormSubmit($form['field']['default_value'], $form, $form_state);
     }
     $this->field->default_value = $default_value;