diff --git a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
index d460416..eb636b4 100644
--- a/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
+++ b/core/modules/datetime/src/Plugin/Field/FieldWidget/DateTimeDatelistWidget.php
@@ -59,11 +59,11 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     }
     switch ($time_type) {
        case '24':
-         $date_part_order = array_merge($date_part_order, array('hour', 'minute'));
+         $date_part_order += ['hour', 'minute'];
          break;
 
        case '12':
-         $date_part_order = array_merge($date_part_order, array('hour', 'minute', 'ampm'));
+         $date_part_order += ['hour', 'minute', 'ampm'];
          break;
 
        case 'none':
@@ -99,25 +99,31 @@ function settingsForm(array $form, FormStateInterface $form_state) {
         '#default_value' => $this->getSetting('time_type'),
         '#options' => array('24' => t('24 hour time'), '12' => t('12 hour time')),
       );
+
+      $element['increment'] = [
+        '#type' => 'select',
+        '#title' => t('Time increments'),
+        '#default_value' => $this->getSetting('increment'),
+        '#options' => [
+          1 => t('1 minute'),
+          5 => t('5 minute'),
+          10 => t('10 minute'),
+          15 => t('15 minute'),
+          30 => t('30 minute'),
+        ],
+      ];
     }
     else {
       $element['time_type'] = array(
         '#type' => 'hidden',
         '#value' => 'none',
       );
-    }
 
-    $element['increment'] = array(
-      '#type' => 'select',
-      '#title' => t('Time increments'),
-      '#default_value' => $this->getSetting('increment'),
-      '#options' => array(
-        1 => t('1 minute'),
-        5 => t('5 minute'),
-        10 => t('10 minute'),
-        15 => t('15 minute'),
-        30 => t('30 minute')),
-    );
+      $element['increment'] = [
+        '#type' => 'hidden',
+        '#value' => $this->getSetting('increment'),
+      ];
+    }
 
     return $element;
   }
@@ -128,11 +134,17 @@ function settingsForm(array $form, FormStateInterface $form_state) {
   public function settingsSummary() {
     $summary = array();
 
-    $summary[] = t('Date part order: !order', array('!order' => $this->getSetting('date_order')));
+    $summary[] = t('Date part order: @order',
+      ['@order' => $this->getSetting('date_order')]
+    );
     if ($this->getFieldSetting('datetime_type') == 'datetime') {
-      $summary[] = t('Time type: !time_type', array('!time_type' => $this->getSetting('time_type')));
+      $summary[] = t('Time type: @time_type',
+        ['@time_type' => $this->getSetting('time_type')]
+      );
+      $summary[] = t('Time increments: @increment',
+        ['@increment' => $this->getSetting('increment')]
+      );
     }
-    $summary[] = t('Time increments: !increment', array('!increment' => $this->getSetting('increment')));
 
     return $summary;
   }