diff -u b/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceSelectionSortTest.php b/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceSelectionSortTest.php
--- b/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceSelectionSortTest.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/Tests/EntityReferenceSelectionSortTest.php
@@ -139,6 +139,10 @@
       'field' => 'nid',
       'direction' => 'ASC',
     );
+    // @todo Field and FieldInstance need an API for reacting to changes to data
+    //   that mergedSettings is derived from. Here, we cheat by affecting a
+    //   protected property via offsetSet().
+    unset($instance['mergedSettings']);
     $handler = entity_reference_get_selection_handler($instance);
     $result = $handler->getReferencableEntities();
     $expected_result = array(
diff -u b/core/modules/number/lib/Drupal/number/Plugin/field/widget/NumberWidget.php b/core/modules/number/lib/Drupal/number/Plugin/field/widget/NumberWidget.php
--- b/core/modules/number/lib/Drupal/number/Plugin/field/widget/NumberWidget.php
+++ b/core/modules/number/lib/Drupal/number/Plugin/field/widget/NumberWidget.php
@@ -80,7 +80,7 @@
       $prefixes = explode('|', $field_settings['prefix']);
       $element['#field_prefix'] = field_filter_xss(array_pop($prefixes));
     }
-    if ($field_settings('suffix')) {
+    if ($field_settings['suffix']) {
       $suffixes = explode('|', $field_settings['suffix']);
       $element['#field_suffix'] = field_filter_xss(array_pop($suffixes));
     }
diff -u b/core/modules/options/options.module b/core/modules/options/options.module
--- b/core/modules/options/options.module
+++ b/core/modules/options/options.module
@@ -8,6 +8,7 @@
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\Field\FieldDefinitionInterface;
+use Drupal\field\FieldInterface;
 use Drupal\field\FieldUpdateForbiddenException;
 use Drupal\options\Plugin\field\widget\OptionsWidgetBase;
 
@@ -221,9 +222,9 @@
 }
 
 /**
- * Implements hook_field_delete_field().
+ * Implements hook_ENTITY_TYPE_delete() for 'field_entity'.
  */
-function options_field_delete_field($field) {
+function options_field_entity_delete(FieldInterface $field) {
   drupal_static_reset('options_allowed_values');
 }