diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index 957c4e9..45e3fe8 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -454,10 +454,13 @@ protected static function invalidateTagsOnDelete(EntityTypeInterface $entity_typ
     Cache::invalidateTags($entity_type->getListCacheTags());
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public static function preDelete(EntityStorageInterface $storage, array $entities) {
     foreach ($entities as $entity) {
       if ($entity->isUninstalling() || $entity->isSyncing()) {
-        // During extension uninstall and configuration synchronisation
+        // During extension uninstall and configuration synchronization
         // deletions are already managed.
         break;
       }
@@ -471,9 +474,6 @@ public static function preDelete(EntityStorageInterface $storage, array $entitie
           'module' => [],
           'theme' => []
         ];
-        // Because we are only passing in one dependency to the
-        // onDependencyRemoval method returns TRUE then we assume that the
-        // dependency has been removed.
         if (!$dependent->onDependencyRemoval($dependencies_for_removal)) {
           $dependent->delete();
         }
@@ -483,5 +483,4 @@ public static function preDelete(EntityStorageInterface $storage, array $entitie
     parent::preDelete($storage, $entities);
   }
 
-
 }
diff --git a/core/lib/Drupal/Core/Entity/EntityDeleteForm.php b/core/lib/Drupal/Core/Entity/EntityDeleteForm.php
index 257a853..93c1c13 100644
--- a/core/lib/Drupal/Core/Entity/EntityDeleteForm.php
+++ b/core/lib/Drupal/Core/Entity/EntityDeleteForm.php
@@ -6,6 +6,7 @@
  */
 
 namespace Drupal\Core\Entity;
+use Drupal\Core\Config\Entity\ConfigEntityInterface;
 use Drupal\Core\Form\FormStateInterface;
 
 /**
@@ -23,6 +24,14 @@ class EntityDeleteForm extends EntityConfirmFormBase {
   public function buildForm(array $form, FormStateInterface $form_state) {
     $form = parent::buildForm($form, $form_state);
     $entity = $this->getEntity();
+    // Only do dependency processing for configuration entities. Whilst it is
+    // possible for a configuration entity to be dependent on a content entity,
+    // these dependencies are soft and content delete permissions are often
+    // given to more users. The in this method should not make assumptions that
+    // $entity is a configuration entity in case we decide to change this later.
+    if (!($entity instanceof ConfigEntityInterface)) {
+      return $form;
+    }
     $dependent_entities = \Drupal::service('config.manager')->findConfigEntityDependentsAsEntities($entity->getConfigDependencyKey(), [$entity->getConfigDependencyName()]);
 
     $form['other_entities'] = array(
@@ -37,7 +46,8 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       $entity_type_id = $dependent_entity->getEntityTypeId();
       if (!isset($form['entities'][$entity_type_id])) {
         $entity_type = $this->entityManager->getDefinition($entity_type_id);
-        // Store the ID and label to sort the dependent_entity types and entities later.
+        // Store the ID and label to sort the dependent_entity types and
+        // entities later.
         $label = $entity_type->getLabel();
         $entity_types[$entity_type_id] = $label;
         $form['other_entities'][$entity_type_id] = array(
@@ -51,7 +61,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
     if (!empty($dependent_entities)) {
       $form['other_entities']['#access'] = TRUE;
 
-      // Add a weight key to the dependent_entity type sections.
+      // Add a weight key to the dependent entity type sections.
       asort($entity_types, SORT_FLAG_CASE);
       $weight = 0;
       foreach ($entity_types as $entity_type_id => $label) {
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
index e45aae7..10497ad 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
@@ -286,6 +286,9 @@ public static function calculateDependencies(FieldDefinitionInterface $field_def
     return $dependencies;
   }
 
+  /**
+   * {@inheritdoc}
+   */
   public static function onDependencyRemoval(FieldDefinitionInterface $field_definition, array $dependencies) {
     $changed = FALSE;
     if (is_array($field_definition->default_value) && count($field_definition->default_value)) {
diff --git a/core/modules/field/src/Entity/FieldStorageConfig.php b/core/modules/field/src/Entity/FieldStorageConfig.php
index 203b961..02fbd0f 100644
--- a/core/modules/field/src/Entity/FieldStorageConfig.php
+++ b/core/modules/field/src/Entity/FieldStorageConfig.php
@@ -202,7 +202,7 @@ class FieldStorageConfig extends ConfigEntityBase implements FieldStorageConfigI
    *
    * @var bool
    */
-  protected static $in_deletion = FALSE;
+  protected static $inDeletion = FALSE;
 
   /**
    * Constructs a FieldStorageConfig object.
@@ -384,7 +384,7 @@ public static function preDelete(EntityStorageInterface $storage, array $field_s
 
     // Set the static flag so that we don't delete field storages whilst
     // deleting fields.
-    self::$in_deletion = TRUE;
+    self::$inDeletion = TRUE;
 
     // Delete or fix any configuration that is dependent, for example, fields.
     parent::preDelete($storage, $field_storages);
@@ -416,7 +416,7 @@ public static function postDelete(EntityStorageInterface $storage, array $fields
       }
     }
     // Unset static flag.
-    self::$in_deletion = FALSE;
+    self::$inDeletion = FALSE;
   }
 
   /**
@@ -739,8 +739,9 @@ public static function loadByName($entity_type_id, $field_name) {
    */
   public function isDeletable() {
     // The field storage is not deleted, is configured to be removed when there
-    // are no fields and the field storage has no bundles.
-    return !$this->deleted && !$this->persist_with_no_fields && count($this->getBundles()) == 0 && !self::$in_deletion;
+    // are no fields, the field storage has no bundles, and field storages are
+    // not in the process of being deleted.
+    return !$this->deleted && !$this->persist_with_no_fields && count($this->getBundles()) == 0 && !self::$inDeletion;
   }
 
 }