diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/DecimalFormatter.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/DecimalFormatter.php
index 9f8c971..4a0436b 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/DecimalFormatter.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/DecimalFormatter.php
@@ -29,12 +29,12 @@ class DecimalFormatter extends NumericFormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['thousand_separator'] = '';
-    $settings['decimal_separator'] = '.';
-    $settings['scale'] = 2;
-    $settings['prefix_suffix'] = TRUE;
-    return $settings;
+    return array(
+      'thousand_separator' => '',
+      'decimal_separator' => '.',
+      'scale' => 2,
+      'prefix_suffix' => TRUE,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/IntegerFormatter.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/IntegerFormatter.php
index 415e324..8768474 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/IntegerFormatter.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldFormatter/IntegerFormatter.php
@@ -28,10 +28,10 @@ class IntegerFormatter extends NumericFormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['thousand_separator'] = '';
-    $settings['prefix_suffix'] = TRUE;
-    return $settings;
+    return array(
+      'thousand_separator' => '',
+      'prefix_suffix' => TRUE,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/DecimalItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/DecimalItem.php
index 75f3fa7..cbb79d8 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/DecimalItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/DecimalItem.php
@@ -27,10 +27,10 @@ class DecimalItem extends NumericItemBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['precision'] = 10;
-    $settings['scale'] = 2;
-    return $settings;
+    return array(
+      'precision' => 10,
+      'scale' => 2,
+    ) + parent::defaultSettings();
   }
 
   /**
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 737f250..a56b406 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
@@ -36,19 +36,19 @@ class EntityReferenceItem extends FieldItemBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['target_type'] = \Drupal::moduleHandler()->moduleExists('node') ? 'node' : 'user';
-    $settings['target_bundle'] = NULL;
-    return $settings;
+    return array(
+      'target_type' => \Drupal::moduleHandler()->moduleExists('node') ? 'node' : 'user',
+      'target_bundle' => NULL,
+    ) + parent::defaultSettings();
   }
 
   /**
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
-    $settings['handler'] = 'default';
-    return $settings;
+    return array(
+      'handler' => 'default',
+    ) + parent::defaultInstanceSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItem.php
index 8fbad2b..1dfd9f4 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItem.php
@@ -29,9 +29,9 @@ class StringItem extends FieldItemBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['max_length'] = 255;
-    return $settings;
+    return array(
+      'max_length' => 255,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UriItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UriItem.php
index ce0d84e..d74a85a 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UriItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UriItem.php
@@ -30,9 +30,9 @@ class UriItem extends StringItem {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['max_length'] = 2048;
-    return $settings;
+    return array(
+      'max_length' => 2048,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UuidItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UuidItem.php
index f7a7e54..15cbe74 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UuidItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/UuidItem.php
@@ -25,9 +25,9 @@ class UuidItem extends StringItem {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['max_length'] = 128;
-    return $settings;
+    return array(
+      'max_length' => 128,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EmailDefaultWidget.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EmailDefaultWidget.php
index 9d7618a..889fbab 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EmailDefaultWidget.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/EmailDefaultWidget.php
@@ -27,9 +27,9 @@ class EmailDefaultWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/NumberWidget.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/NumberWidget.php
index b26bf73..fa31ce7 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/NumberWidget.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/NumberWidget.php
@@ -30,9 +30,9 @@ class NumberWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringWidget.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringWidget.php
index dc6eaaa..ed1d928 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringWidget.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringWidget.php
@@ -27,10 +27,10 @@ class StringWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['size'] = 60;
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'size' => 60,
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php b/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
index fd0dff0..16521b5 100644
--- a/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
+++ b/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldFormatter/CommentDefaultFormatter.php
@@ -38,9 +38,9 @@ class CommentDefaultFormatter extends FormatterBase implements ContainerFactoryP
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['pager_id'] = 0;
-    return $settings;
+    return array(
+      'pager_id' => 0,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldType/CommentItem.php b/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldType/CommentItem.php
index eb47c57..477ca36 100644
--- a/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldType/CommentItem.php
+++ b/core/modules/comment/lib/Drupal/comment/Plugin/Field/FieldType/CommentItem.php
@@ -28,23 +28,23 @@ class CommentItem extends FieldItemBase implements CommentItemInterface {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['description'] = '';
-    return $settings;
+    return array(
+      'description' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
-    $settings['default_mode'] = COMMENT_MODE_THREADED;
-    $settings['per_page'] = 50;
-    $settings['form_location'] = COMMENT_FORM_BELOW;
-    $settings['anonymous'] = COMMENT_ANONYMOUS_MAYNOT_CONTACT;
-    $settings['subject'] = 1;
-    $settings['preview'] = DRUPAL_OPTIONAL;
-    return $settings;
+    return array(
+      'default_mode' => COMMENT_MODE_THREADED,
+      'per_page' => 50,
+      'form_location' => COMMENT_FORM_BELOW,
+      'anonymous' => COMMENT_ANONYMOUS_MAYNOT_CONTACT,
+      'subject' => 1,
+      'preview' => DRUPAL_OPTIONAL,
+    ) + parent::defaultInstanceSettings();
   }
 
   /**
diff --git a/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php b/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php
index f780968..3680072 100644
--- a/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php
+++ b/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldFormatter/DateTimeDefaultFormatter.php
@@ -33,9 +33,9 @@ class DateTimeDefaultFormatter extends FormatterBase implements ContainerFactory
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['format_type'] = 'medium';
-    return $settings;
+    return array(
+      'format_type' => 'medium',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldType/DateTimeItem.php b/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldType/DateTimeItem.php
index 935e19e..e600079 100644
--- a/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldType/DateTimeItem.php
+++ b/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldType/DateTimeItem.php
@@ -30,9 +30,9 @@ class DateTimeItem extends FieldItemBase implements PrepareCacheInterface {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['datetime_type'] = 'datetime';
-    return $settings;
+    return array(
+      'datetime_type' => 'datetime',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php b/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
index 0f36a3d..c9c3195 100644
--- a/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
+++ b/core/modules/datetime/lib/Drupal/datetime/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
@@ -27,11 +27,11 @@ class DateTimeDatelistWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['increment'] = '15';
-    $settings['date_order'] = 'YMD';
-    $settings['time_type'] = '24';
-    return $settings;
+    return array(
+      'increment' => '15',
+      'date_order' => 'YMD',
+      'time_type' => '24',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php b/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php
index 91092f3..550f3d7 100644
--- a/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php
@@ -43,9 +43,9 @@ public static function defaultSettings() {
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
-    $settings['handler_settings'] = array();
-    return $settings;
+    return array(
+      'handler_settings' => array(),
+    ) + parent::defaultInstanceSettings();
   }
 
   /**
diff --git a/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php.rej b/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php.rej
new file mode 100644
index 0000000..9039435
--- /dev/null
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php.rej
@@ -0,0 +1,10 @@
+diff a/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php b/core/modules/entity_reference/lib/Drupal/entity_reference/ConfigurableEntityReferenceItem.php	(rejected hunks)
+@@ -33,7 +33,7 @@ class ConfigurableEntityReferenceItem extends EntityReferenceItem implements All
+    */
+   public static function defaultSettings() {
+     $settings = parent::defaultSettings();
+-    // The instance settings 'handler_settings.target_bundles' used for this.
++    // The instance setting 'handler_settings.target_bundles' is used for this.
+     unset($settings['target_bundle']);
+     return $settings;
+   }
diff --git a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceEntityFormatter.php b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceEntityFormatter.php
index bd81dbf..623140f 100644
--- a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceEntityFormatter.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceEntityFormatter.php
@@ -28,10 +28,10 @@ class EntityReferenceEntityFormatter extends EntityReferenceFormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['view_mode'] = 'default';
-    $settings['link'] = FALSE;
-    return $settings;
+    return array(
+      'view_mode' => 'default',
+      'link' => FALSE,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceLabelFormatter.php b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceLabelFormatter.php
index d832fb1..a062f0b 100644
--- a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceLabelFormatter.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldFormatter/EntityReferenceLabelFormatter.php
@@ -27,9 +27,9 @@ class EntityReferenceLabelFormatter extends EntityReferenceFormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['link'] = TRUE;
-    return $settings;
+    return array(
+      'link' => TRUE,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteTagsWidget.php b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteTagsWidget.php
index 3d512b0..f930de2 100644
--- a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteTagsWidget.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteTagsWidget.php
@@ -28,12 +28,12 @@ class AutocompleteTagsWidget extends AutocompleteWidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['match_operator'] = 'CONTAINS';
-    $settings['size'] = '60';
-    $settings['autocomplete_type'] = 'tags';
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'match_operator' => 'CONTAINS',
+      'size' => '60',
+      'autocomplete_type' => 'tags',
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php
index b9ed95b..234eb7a 100644
--- a/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php
+++ b/core/modules/entity_reference/lib/Drupal/entity_reference/Plugin/Field/FieldWidget/AutocompleteWidget.php
@@ -34,12 +34,12 @@ class AutocompleteWidget extends AutocompleteWidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['match_operator'] = 'CONTAINS';
-    $settings['size'] = '60';
-    $settings['autocomplete_type'] = 'tags';
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'match_operator' => 'CONTAINS',
+      'size' => '60',
+      'autocomplete_type' => 'tags',
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldDefaultFormatter.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldDefaultFormatter.php
index 953210b..3e61ca1 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldDefaultFormatter.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldDefaultFormatter.php
@@ -29,9 +29,9 @@ class TestFieldDefaultFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['test_formatter_setting'] = 'dummy test string';
-    return $settings;
+    return array(
+      'test_formatter_setting' => 'dummy test string',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptyFormatter.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptyFormatter.php
index 08fbc3f..4b9bb4b 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptyFormatter.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptyFormatter.php
@@ -28,9 +28,9 @@ class TestFieldEmptyFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['test_empty_string'] = '**EMPTY FIELD**';
-    return $settings;
+    return array(
+      'test_empty_string' => '**EMPTY FIELD**',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptySettingFormatter.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptySettingFormatter.php
index ae73e19..7cd25fb 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptySettingFormatter.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldEmptySettingFormatter.php
@@ -28,9 +28,9 @@ class TestFieldEmptySettingFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['field_empty_setting'] = '';
-    return $settings;
+    return array(
+      'field_empty_setting' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldMultipleFormatter.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldMultipleFormatter.php
index ef624b3..1aeb570 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldMultipleFormatter.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldMultipleFormatter.php
@@ -29,9 +29,9 @@ class TestFieldMultipleFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['test_formatter_setting_multiple'] = 'dummy test string';
-    return $settings;
+    return array(
+      'test_formatter_setting_multiple' => 'dummy test string',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldPrepareViewFormatter.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldPrepareViewFormatter.php
index 1b92ab7..beb17e9 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldPrepareViewFormatter.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldFormatter/TestFieldPrepareViewFormatter.php
@@ -29,9 +29,9 @@ class TestFieldPrepareViewFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['test_formatter_setting_additional'] = 'dummy test string';
-    return $settings;
+    return array(
+      'test_formatter_setting_additional' => 'dummy test string',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/ShapeItem.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/ShapeItem.php
index 4e80454..58985b8 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/ShapeItem.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/ShapeItem.php
@@ -28,9 +28,9 @@ class ShapeItem extends FieldItemBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['foreign_key_name'] = 'shape';
-    return $settings;
+    return array(
+      'foreign_key_name' => 'shape',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/TestItem.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/TestItem.php
index 14e3f6e..b3326ef 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/TestItem.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldType/TestItem.php
@@ -29,21 +29,21 @@ class TestItem extends FieldItemBase implements PrepareCacheInterface {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['test_field_setting'] = 'dummy test string';
-    $settings['changeable'] = 'a changeable field setting';
-    $settings['unchangeable'] = 'an unchangeable field setting';
-    return $settings;
+    return array(
+      'test_field_setting' => 'dummy test string',
+      'changeable' => 'a changeable field setting',
+      'unchangeable' => 'an unchangeable field setting',
+    ) + parent::defaultSettings();
   }
 
   /**
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
-    $settings['test_instance_setting'] = 'dummy test string';
-    $settings['test_cached_data'] = FALSE;
-    return $settings;
+    return array(
+      'test_instance_setting' => 'dummy test string',
+      'test_cached_data' => FALSE,
+    ) + parent::defaultInstanceSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidget.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidget.php
index 7e29cb9..1fcc8bc 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidget.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidget.php
@@ -30,9 +30,9 @@ class TestFieldWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['test_widget_setting'] = 'dummy test string';
-    return $settings;
+    return array(
+      'test_widget_setting' => 'dummy test string',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidgetMultiple.php b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidgetMultiple.php
index 006faa4..ac4609c 100644
--- a/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidgetMultiple.php
+++ b/core/modules/field/tests/modules/field_test/lib/Drupal/field_test/Plugin/Field/FieldWidget/TestFieldWidgetMultiple.php
@@ -32,9 +32,9 @@ class TestFieldWidgetMultiple extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['test_widget_setting_multiple'] = 'dummy test string';
-    return $settings;
+    return array(
+      'test_widget_setting_multiple' => 'dummy test string',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/file/lib/Drupal/file/Plugin/Field/FieldType/FileItem.php b/core/modules/file/lib/Drupal/file/Plugin/Field/FieldType/FileItem.php
index b5ed522..7e66420 100644
--- a/core/modules/file/lib/Drupal/file/Plugin/Field/FieldType/FileItem.php
+++ b/core/modules/file/lib/Drupal/file/Plugin/Field/FieldType/FileItem.php
@@ -29,24 +29,24 @@ class FileItem extends EntityReferenceItem {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['target_type'] = 'file';
-    $settings['display_field'] = 0;
-    $settings['display_default'] = 0;
-    $settings['uri_scheme'] = file_default_scheme();
-    return $settings;
+    return array(
+      'target_type' => 'file',
+      'display_field' => 0,
+      'display_default' => 0,
+      'uri_scheme' => file_default_scheme(),
+    ) + parent::defaultSettings();
   }
 
   /**
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
-    $settings['file_extensions'] = 'txt';
-    $settings['file_directory'] = '';
-    $settings['max_filesize'] = '';
-    $settings['description_field'] = 0;
-    return $settings;
+    return array(
+      'file_extensions' => 'txt',
+      'file_directory' => '',
+      'max_filesize' => '',
+      'description_field' => 0,
+    ) + parent::defaultInstanceSettings();
   }
 
   /**
diff --git a/core/modules/file/lib/Drupal/file/Plugin/Field/FieldWidget/FileWidget.php b/core/modules/file/lib/Drupal/file/Plugin/Field/FieldWidget/FileWidget.php
index d547d86..460b95e 100644
--- a/core/modules/file/lib/Drupal/file/Plugin/Field/FieldWidget/FileWidget.php
+++ b/core/modules/file/lib/Drupal/file/Plugin/Field/FieldWidget/FileWidget.php
@@ -30,9 +30,9 @@ class FileWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['progress_indicator'] = 'throbber';
-    return $settings;
+    return array(
+      'progress_indicator' => 'throbber',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldFormatter/ImageFormatter.php b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldFormatter/ImageFormatter.php
index 4ae4887..69bf5f5 100644
--- a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldFormatter/ImageFormatter.php
+++ b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldFormatter/ImageFormatter.php
@@ -26,10 +26,10 @@ class ImageFormatter extends ImageFormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['image_style'] = '';
-    $settings['image_link'] = '';
-    return $settings;
+    return array(
+      'image_style' => '',
+      'image_link' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
index ca048f8..f664bb8 100644
--- a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
+++ b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldType/ImageItem.php
@@ -29,50 +29,52 @@ class ImageItem extends FileItem {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['default_image'] = array(
-      'fid' => NULL,
-      'alt' => '',
-      'title' => '',
-      'width' => NULL,
-      'height' => NULL,
-    );
-    $settings['column_groups'] = array(
-      'file' => array(
-        'label' => t('File'),
-        'columns' => array('target_id', 'width', 'height'),
-      ),
-      'alt' => array(
-        'label' => t('Alt'),
-        'translatable' => TRUE,
+    return array(
+      'default_image' => array(
+        'fid' => NULL,
+        'alt' => '',
+        'title' => '',
+        'width' => NULL,
+        'height' => NULL,
       ),
-      'title' => array(
-        'label' => t('Title'),
-        'translatable' => TRUE,
+      'column_groups' => array(
+        'file' => array(
+          'label' => t('File'),
+          'columns' => array('target_id', 'width', 'height'),
+        ),
+        'alt' => array(
+          'label' => t('Alt'),
+          'translatable' => TRUE,
+        ),
+        'title' => array(
+          'label' => t('Title'),
+          'translatable' => TRUE,
+        ),
       ),
-    );
-    return $settings;
+    ) + parent::defaultSettings();
   }
 
   /**
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
+    $settings = array(
+      'file_extensions' => 'png gif jpg jpeg',
+      'alt_field' => 0,
+      'alt_field_required' => 0,
+      'title_field' => 0,
+      'title_field_required' => 0,
+      'max_resolution' => '',
+      'min_resolution' => '',
+      'default_image' => array(
+        'fid' => NULL,
+        'alt' => '',
+        'width' => NULL,
+        'height' => NULL,
+      ),
+    ) + parent::defaultInstanceSettings();
+
     unset($settings['description_field']);
-    $settings['file_extensions'] = 'png gif jpg jpeg';
-    $settings['alt_field'] = 0;
-    $settings['alt_field_required'] = 0;
-    $settings['title_field'] = 0;
-    $settings['title_field_required'] = 0;
-    $settings['max_resolution'] = '';
-    $settings['min_resolution'] = '';
-    $settings['default_image'] = array(
-      'fid' => NULL,
-      'alt' => '',
-      'width' => NULL,
-      'height' => NULL,
-    );
     return $settings;
   }
 
diff --git a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldWidget/ImageWidget.php b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldWidget/ImageWidget.php
index 9f7c71c..811ed0f 100644
--- a/core/modules/image/lib/Drupal/image/Plugin/Field/FieldWidget/ImageWidget.php
+++ b/core/modules/image/lib/Drupal/image/Plugin/Field/FieldWidget/ImageWidget.php
@@ -28,10 +28,10 @@ class ImageWidget extends FileWidget {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['progress_indicator'] = 'throbber';
-    $settings['preview_image_style'] = 'thumbnail';
-    return $settings;
+    return array(
+      'progress_indicator' => 'throbber',
+      'preview_image_style' => 'thumbnail',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkFormatter.php b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkFormatter.php
index e133464..fd8db1c 100644
--- a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkFormatter.php
+++ b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkFormatter.php
@@ -30,13 +30,13 @@ class LinkFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['trim_length'] = '80';
-    $settings['url_only'] = '';
-    $settings['url_plain'] = '';
-    $settings['rel'] = '';
-    $settings['target'] = '';
-    return $settings;
+    return array(
+      'trim_length' => '80',
+      'url_only' => '',
+      'url_plain' => '',
+      'rel' => '',
+      'target' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkSeparateFormatter.php b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkSeparateFormatter.php
index 6f97cd5..a123e80 100644
--- a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkSeparateFormatter.php
+++ b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldFormatter/LinkSeparateFormatter.php
@@ -31,11 +31,11 @@ class LinkSeparateFormatter extends LinkFormatter {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['trim_length'] = '80';
-    $settings['rel'] = '';
-    $settings['target'] = '';
-    return $settings;
+    return array(
+      'trim_length' => '80',
+      'rel' => '',
+      'target' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldType/LinkItem.php b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldType/LinkItem.php
index 3bef68e..58a5826 100644
--- a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldType/LinkItem.php
+++ b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldType/LinkItem.php
@@ -29,9 +29,9 @@ class LinkItem extends FieldItemBase {
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
-    $settings['title'] = 1;
-    return $settings;
+    return array(
+      'title' => 1,
+    ) + parent::defaultInstanceSettings();
   }
 
   /**
diff --git a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldWidget/LinkWidget.php b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldWidget/LinkWidget.php
index 7b2469c..7f69639 100644
--- a/core/modules/link/lib/Drupal/link/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/lib/Drupal/link/Plugin/Field/FieldWidget/LinkWidget.php
@@ -27,10 +27,10 @@ class LinkWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['placeholder_url'] = '';
-    $settings['placeholder_title'] = '';
-    return $settings;
+    return array(
+      'placeholder_url' => '',
+      'placeholder_title' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
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 65e374c..b1816f2 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
@@ -20,10 +20,10 @@
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['allowed_values'] = array();
-    $settings['allowed_values_function'] = '';
-    return $settings;
+    return array(
+      'allowed_values' => array(),
+      'allowed_values_function' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/options/lib/Drupal/options/Plugin/Field/FieldWidget/OnOffWidget.php b/core/modules/options/lib/Drupal/options/Plugin/Field/FieldWidget/OnOffWidget.php
index 059af18..731f3b2 100644
--- a/core/modules/options/lib/Drupal/options/Plugin/Field/FieldWidget/OnOffWidget.php
+++ b/core/modules/options/lib/Drupal/options/Plugin/Field/FieldWidget/OnOffWidget.php
@@ -28,9 +28,9 @@ class OnOffWidget extends OptionsWidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['display_label'] = FALSE;
-    return $settings;
+    return array(
+      'display_label' => FALSE,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/responsive_image/lib/Drupal/responsive_image/Plugin/Field/FieldFormatter/ResponsiveImageFormatter.php b/core/modules/responsive_image/lib/Drupal/responsive_image/Plugin/Field/FieldFormatter/ResponsiveImageFormatter.php
index 1020a6f..dc82c66 100644
--- a/core/modules/responsive_image/lib/Drupal/responsive_image/Plugin/Field/FieldFormatter/ResponsiveImageFormatter.php
+++ b/core/modules/responsive_image/lib/Drupal/responsive_image/Plugin/Field/FieldFormatter/ResponsiveImageFormatter.php
@@ -27,11 +27,11 @@ class ResponsiveImageFormatter extends ImageFormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['responsive_image_mapping'] = '';
-    $settings['fallback_image_style'] = '';
-    $settings['image_link'] = '';
-    return $settings;
+    return array(
+      'responsive_image_mapping' => '',
+      'fallback_image_style' => '',
+      'image_link' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldType/TaxonomyTermReferenceItem.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldType/TaxonomyTermReferenceItem.php
index cb2ec96..eaa2103 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldType/TaxonomyTermReferenceItem.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldType/TaxonomyTermReferenceItem.php
@@ -30,16 +30,16 @@ class TaxonomyTermReferenceItem extends EntityReferenceItem implements AllowedVa
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['target_type'] = 'taxonomy_term';
-    $settings['options_list_callback'] = NULL;
-    $settings['allowed_values'] = array(
-      array(
-        'vocabulary' => '',
-        'parent' => 0,
+    return array(
+      'target_type' => 'taxonomy_term',
+      'options_list_callback' => NULL,
+      'allowed_values' => array(
+        array(
+          'vocabulary' => '',
+          'parent' => 0,
+        ),
       ),
-    );
-    return $settings;
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldWidget/TaxonomyAutocompleteWidget.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldWidget/TaxonomyAutocompleteWidget.php
index 846e011..4d7fe8f 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldWidget/TaxonomyAutocompleteWidget.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/Field/FieldWidget/TaxonomyAutocompleteWidget.php
@@ -28,11 +28,11 @@ class TaxonomyAutocompleteWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['size'] = '60';
-    $settings['autocomplete_route_name'] = 'taxonomy.autocomplete';
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'size' => '60',
+      'autocomplete_route_name' => 'taxonomy.autocomplete',
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldFormatter/TelephoneLinkFormatter.php b/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldFormatter/TelephoneLinkFormatter.php
index 529a786..dfab549 100644
--- a/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldFormatter/TelephoneLinkFormatter.php
+++ b/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldFormatter/TelephoneLinkFormatter.php
@@ -27,9 +27,9 @@ class TelephoneLinkFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['title'] = '';
-    return $settings;
+    return array(
+      'title' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldWidget/TelephoneDefaultWidget.php b/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldWidget/TelephoneDefaultWidget.php
index 4c3dd5d..0bdd1c8 100644
--- a/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldWidget/TelephoneDefaultWidget.php
+++ b/core/modules/telephone/lib/Drupal/telephone/Plugin/Field/FieldWidget/TelephoneDefaultWidget.php
@@ -27,9 +27,9 @@ class TelephoneDefaultWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldFormatter/TextTrimmedFormatter.php b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldFormatter/TextTrimmedFormatter.php
index fa8765a..c0901da 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldFormatter/TextTrimmedFormatter.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldFormatter/TextTrimmedFormatter.php
@@ -36,9 +36,9 @@ class TextTrimmedFormatter extends FormatterBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['trim_length'] = '600';
-    return $settings;
+    return array(
+      'trim_length' => '600',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextItem.php b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextItem.php
index 5eb7c92..49ca7f1 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextItem.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextItem.php
@@ -26,9 +26,9 @@ class TextItem extends TextItemBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['max_length'] = 255;
-    return $settings;
+    return array(
+      'max_length' => 255,
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php
index f9307ce..8cb505f 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldType/TextWithSummaryItem.php
@@ -27,10 +27,10 @@ class TextWithSummaryItem extends TextItemBase {
    * {@inheritdoc}
    */
   public static function defaultInstanceSettings() {
-    $settings = parent::defaultInstanceSettings();
-    $settings['text_processing'] = 1;
-    $settings['display_summary'] = 0;
-    return $settings;
+    return array(
+      'text_processing' => 1,
+      'display_summary' => 0,
+    ) + parent::defaultInstanceSettings();
   }
 
   /**
diff --git a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWidget.php b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWidget.php
index 104ecca..3c57008 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWidget.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWidget.php
@@ -28,10 +28,10 @@ class TextareaWidget extends WidgetBase {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['rows'] = '5';
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'rows' => '5',
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**
diff --git a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWithSummaryWidget.php b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWithSummaryWidget.php
index f715f8f..e23e794 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWithSummaryWidget.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/Field/FieldWidget/TextareaWithSummaryWidget.php
@@ -28,11 +28,11 @@ class TextareaWithSummaryWidget extends TextareaWidget {
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    $settings = parent::defaultSettings();
-    $settings['rows'] = '9';
-    $settings['summary_rows'] = '3';
-    $settings['placeholder'] = '';
-    return $settings;
+    return array(
+      'rows' => '9',
+      'summary_rows' => '3',
+      'placeholder' => '',
+    ) + parent::defaultSettings();
   }
 
   /**