commit 4694efa2d2c5d3594665003b1505c4ae8fdd8e68
Author: Matthew Radcliffe <mradcliffe@softpixel.com>
Date:   Sun Dec 15 21:49:20 2013 -0500

    Issue #2015689 by mradcliffe: Fix API change from getFieldSetting to getSetting for singular and plural methods change in #2143263.

diff --git a/core/modules/options/lib/Drupal/options/Plugin/Field/FieldType/ListItemBase.php b/core/modules/options/lib/Drupal/options/Plugin/Field/FieldType/ListItemBase.php
index 2d4f2a6..d614277 100644
--- a/core/modules/options/lib/Drupal/options/Plugin/Field/FieldType/ListItemBase.php
+++ b/core/modules/options/lib/Drupal/options/Plugin/Field/FieldType/ListItemBase.php
@@ -77,7 +77,7 @@ public static function schema(FieldInterface $field) {
   public function settingsForm(array $form, array &$form_state, $has_data) {
     $instance = $this->getFieldDefinition();
     $field = $instance->getField();
-    $settings = $field->getFieldSettings();
+    $settings = $field->getSettings();
 
     if (in_array($field->type, array('list_integer', 'list_float', 'list_text'))) {
       $element['allowed_values'] = array(
@@ -216,7 +216,7 @@ public function validateAllowedValues($element, &$form_state) {
 
       // Prevent removing values currently in use.
       if ($has_data) {
-        $lost_keys = array_diff(array_keys($field->getFieldSetting('allowed_values')), array_keys($values));
+        $lost_keys = array_diff(array_keys($field->getSetting('allowed_values')), array_keys($values));
         if (_options_values_in_use($field, $lost_keys)) {
           \Drupal::formBuilder()->setError($element, $form_state, t('Allowed values list: some values are being removed while currently in use.'));
         }