diff --git a/core/modules/datetime_range/datetime_range.install b/core/modules/datetime_range/datetime_range.install
index 53ed7b49b3..780b3b2f54 100644
--- a/core/modules/datetime_range/datetime_range.install
+++ b/core/modules/datetime_range/datetime_range.install
@@ -13,7 +13,7 @@ function datetime_range_update_8600() {
   $storage_schema = \Drupal::keyValue('entity.storage_schema.sql');
   $configs = \Drupal::entityTypeManager()
     ->getStorage('field_storage_config')
-    ->loadByProperties(array('type' => 'daterange'));
+    ->loadByProperties(['type' => 'daterange']);
 
   foreach ($configs as $config) {
     $schema_key = $config->getTargetEntityTypeId() . '.field_schema_data.' . $config->getName();
diff --git a/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php b/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
index 55615c99c3..f1f9b2ff4a 100644
--- a/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
+++ b/core/modules/datetime_range/src/Plugin/Field/FieldWidget/DateRangeWidgetBase.php
@@ -28,7 +28,7 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     $element['value']['#title'] = $this->t('Start date');
 
     $element['end_value'] = [
-      '#title' => $optional_end_date ? $this->t('End date (optional)'): $this->t('End date'),
+      '#title' => $optional_end_date ? $this->t('End date (optional)') : $this->t('End date'),
     ] + $element['value'];
 
     if ($element['#required'] && $optional_end_date) {
@@ -131,15 +131,17 @@ public function validateStartEnd(array &$element, FormStateInterface $form_state
     $start_date = $element['value']['#value']['object'];
     $end_date = $element['end_value']['#value']['object'];
 
-    if (!$this->getFieldSetting('optional_end_date') && $end_date === NULL) {
-      $form_state->setError($element['end_value'], $this->t('The @title end date is required', ['@title' => $element['#title']]));
-    }
+    if ($start_date instanceof DrupalDateTime) {
+      if (!$this->getFieldSetting('optional_end_date') && $end_date === NULL) {
+        $form_state->setError($element['end_value'], $this->t('The @title end date is required', ['@title' => $element['#title']]));
+      }
 
-    if ($start_date instanceof DrupalDateTime && $end_date instanceof DrupalDateTime) {
-      if ($start_date->getTimestamp() !== $end_date->getTimestamp()) {
-        $interval = $start_date->diff($end_date);
-        if ($interval->invert === 1) {
-          $form_state->setError($element, $this->t('The @title end date cannot be before the start date', ['@title' => $element['#title']]));
+      if ($end_date instanceof DrupalDateTime) {
+        if ($start_date->getTimestamp() !== $end_date->getTimestamp()) {
+          $interval = $start_date->diff($end_date);
+          if ($interval->invert === 1) {
+            $form_state->setError($element, $this->t('The @title end date cannot be before the start date', ['@title' => $element['#title']]));
+          }
         }
       }
     }
diff --git a/core/modules/datetime_range/tests/src/Functional/Update/DateRangeUpdateTest.php b/core/modules/datetime_range/tests/src/Functional/Update/DateRangeUpdateTest.php
index 1174167566..9a0ff70e2e 100644
--- a/core/modules/datetime_range/tests/src/Functional/Update/DateRangeUpdateTest.php
+++ b/core/modules/datetime_range/tests/src/Functional/Update/DateRangeUpdateTest.php
@@ -3,10 +3,6 @@
 namespace Drupal\Tests\datetime_range\Functional\Update;
 
 use Drupal\FunctionalTests\Update\UpdatePathTestBase;
-use Drupal\node\Entity\Node;
-use Drupal\datetime\Plugin\Field\FieldType\DateTimeItem;
-use Drupal\field\Entity\FieldConfig;
-use Drupal\field\Entity\FieldStorageConfig;
 
 /**
  * Tests datetime_range update paths.
@@ -45,41 +41,41 @@ protected function setDatabaseDumpFiles() {
    *
    * @see datetime_range_update_8600()
    */
-   public function testEndValueNull() {
-     // Check all storage types before update.
-     $this->assertEndValueNotNull('node', 'field_daterange_allday', TRUE);
-     $this->assertEndValueNotNull('node', 'field_daterange_date', TRUE);
-     $this->assertEndValueNotNull('node', 'field_daterange_datetime', TRUE);
+  public function testEndValueNull() {
+    // Check all storage types before update.
+    $this->assertEndValueNotNull('node', 'field_daterange_allday', TRUE);
+    $this->assertEndValueNotNull('node', 'field_daterange_date', TRUE);
+    $this->assertEndValueNotNull('node', 'field_daterange_datetime', TRUE);
 
-     // Check a not revisinable field before update.
-     $this->assertEndValueNotNull('taxonomy_term', 'field_daterange_not_revisionable', TRUE);
+    // Check a not revisinable field before update.
+    $this->assertEndValueNotNull('taxonomy_term', 'field_daterange_not_revisionable', TRUE);
 
-     $this->runUpdates();
+    $this->runUpdates();
 
-     // Check all the storage types now allow null.
-     $this->assertEndValueNotNull('node', 'field_daterange_allday', FALSE);
-     $this->assertEndValueNotNull('node', 'field_daterange_date', FALSE);
-     $this->assertEndValueNotNull('node', 'field_daterange_datetime', FALSE);
+    // Check all the storage types now allow null.
+    $this->assertEndValueNotNull('node', 'field_daterange_allday', FALSE);
+    $this->assertEndValueNotNull('node', 'field_daterange_date', FALSE);
+    $this->assertEndValueNotNull('node', 'field_daterange_datetime', FALSE);
 
-     // Check the not revisinable field now allow null.
-     $this->assertEndValueNotNull('taxonomy_term', 'field_daterange_not_revisionable', FALSE);
-   }
+    // Check the not revisinable field now allow null.
+    $this->assertEndValueNotNull('taxonomy_term', 'field_daterange_not_revisionable', FALSE);
+  }
 
-   /**
-    * Asserts that a config depends on 'entity_reference' or not
-    *
-    * @param string $entity_type
-    *   The entity type, the field belongs to.
-    * @param string $field_name
-    *   Name of the field
-    * @param bool $expected
-    *   The value expected of not null.
-    */
-   protected function assertEndValueNotNull($entity_type, $field_name, $expected) {
-     $schema_key = $entity_type . '.field_schema_data.' . $field_name;
-     foreach ($this->installedStorageSchema->get($schema_key) as $table) {
-       $this->assertEquals($expected, $table['fields'][$field_name . '_end_value']['not null']);
-     }
-   }
+  /**
+   * Asserts that a config depends on 'entity_reference' or not
+   *
+   * @param string $entity_type
+   *   The entity type, the field belongs to.
+   * @param string $field_name
+   *   Name of the field
+   * @param bool $expected
+   *   The value expected of not null.
+   */
+  protected function assertEndValueNotNull($entity_type, $field_name, $expected) {
+    $schema_key = $entity_type . '.field_schema_data.' . $field_name;
+    foreach ($this->installedStorageSchema->get($schema_key) as $table) {
+      $this->assertEquals($expected, $table['fields'][$field_name . '_end_value']['not null']);
+    }
+  }
 
 }