diff --git a/core/lib/Drupal/Core/Entity/ContentEntityConfirmFormBase.php b/core/lib/Drupal/Core/Entity/ContentEntityConfirmFormBase.php
index 887fcae..a2874ce 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityConfirmFormBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityConfirmFormBase.php
@@ -121,7 +121,7 @@ public function delete(array $form, FormStateInterface $form_state) {}
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     // Override the default validation implementation as it is not necessary
     // nor possible to validate an entity in a confirmation form.
   }
diff --git a/core/lib/Drupal/Core/Entity/ContentEntityForm.php b/core/lib/Drupal/Core/Entity/ContentEntityForm.php
index 58b5ca4..b8808fb 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityForm.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityForm.php
@@ -68,7 +68,7 @@ public function form(array $form, FormStateInterface $form_state) {
    * For more information about entity validation, see
    * https://www.drupal.org/node/2015613.
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
     $entity = $this->buildEntity($form, $form_state);
     $this->getFormDisplay($form_state)->validateFormValues($entity, $form, $form_state);
diff --git a/core/lib/Drupal/Core/Entity/EntityForm.php b/core/lib/Drupal/Core/Entity/EntityForm.php
index 921692a..30d8aa2 100644
--- a/core/lib/Drupal/Core/Entity/EntityForm.php
+++ b/core/lib/Drupal/Core/Entity/EntityForm.php
@@ -230,7 +230,7 @@ protected function actions(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Entity/EntityFormInterface.php b/core/lib/Drupal/Core/Entity/EntityFormInterface.php
index 29b248b..d37f56c 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormInterface.php
@@ -105,7 +105,7 @@ public function buildEntity(array $form, FormStateInterface $form_state);
    * @return \Drupal\Core\Entity\ContentEntityTypeInterface
    *   The built entity.
    */
-  public function validate(array $form, FormStateInterface $form_state);
+  public function validate(array &$form, FormStateInterface $form_state);
 
   /**
    * Form submission handler for the 'save' action.
diff --git a/core/modules/action/src/ActionFormBase.php b/core/modules/action/src/ActionFormBase.php
index 96bb63d..864a067 100644
--- a/core/modules/action/src/ActionFormBase.php
+++ b/core/modules/action/src/ActionFormBase.php
@@ -123,7 +123,7 @@ protected function actions(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     if ($this->plugin instanceof PluginFormInterface) {
diff --git a/core/modules/block/src/BlockForm.php b/core/modules/block/src/BlockForm.php
index 3ff21f6..52dbe5d 100644
--- a/core/modules/block/src/BlockForm.php
+++ b/core/modules/block/src/BlockForm.php
@@ -272,7 +272,7 @@ protected function actions(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     // The Block Entity form puts all block plugin form elements in the
diff --git a/core/modules/block_content/src/BlockContentForm.php b/core/modules/block_content/src/BlockContentForm.php
index 379e576..715409d 100644
--- a/core/modules/block_content/src/BlockContentForm.php
+++ b/core/modules/block_content/src/BlockContentForm.php
@@ -223,8 +223,9 @@ public function save(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validateForm(array &$form, FormStateInterface $form_state) {
-    if ($this->entity->isNew()) {
+  public function validate(array &$form, FormStateInterface $form_state) {
+    $entity = parent::validate($form, $form_state);
+    if ($entity->isNew()) {
       $exists = $this->blockContentStorage->loadByProperties(array('info' => $form_state->getValue(['info', 0, 'value'])));
       if (!empty($exists)) {
         $form_state->setErrorByName('info', $this->t('A block with description %name already exists.', array(
@@ -232,6 +233,7 @@ public function validateForm(array &$form, FormStateInterface $form_state) {
         )));
       }
     }
+    return $entity;
   }
 
 }
diff --git a/core/modules/comment/src/CommentForm.php b/core/modules/comment/src/CommentForm.php
index 95629b2..b5a75ff 100644
--- a/core/modules/comment/src/CommentForm.php
+++ b/core/modules/comment/src/CommentForm.php
@@ -297,7 +297,7 @@ public function buildEntity(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     $comment = parent::validate($form, $form_state);
 
     // Customly trigger validation of manually added fields and add in
diff --git a/core/modules/contact/src/ContactFormEditForm.php b/core/modules/contact/src/ContactFormEditForm.php
index 3300c59..6b80e0e 100644
--- a/core/modules/contact/src/ContactFormEditForm.php
+++ b/core/modules/contact/src/ContactFormEditForm.php
@@ -112,7 +112,7 @@ public function form(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     // Validate and each email recipient.
diff --git a/core/modules/editor/editor.module b/core/modules/editor/editor.module
index 2c53d24..6350ce6 100644
--- a/core/modules/editor/editor.module
+++ b/core/modules/editor/editor.module
@@ -160,7 +160,7 @@ function editor_form_filter_format_form_alter(&$form, FormStateInterface $form_s
     $form['actions']['submit']['#submit'][] = array($plugin, 'settingsFormSubmit');
   }
 
-  $form['#validate'][] = 'editor_form_filter_admin_format_validate';
+  $form['actions']['submit']['#validate'][] = 'editor_form_filter_admin_format_validate';
   $form['actions']['submit']['#submit'][] = 'editor_form_filter_admin_format_submit';
 }
 
diff --git a/core/modules/field_ui/src/Form/EntityDisplayModeAddForm.php b/core/modules/field_ui/src/Form/EntityDisplayModeAddForm.php
index d6d801b..4c83b50 100644
--- a/core/modules/field_ui/src/Form/EntityDisplayModeAddForm.php
+++ b/core/modules/field_ui/src/Form/EntityDisplayModeAddForm.php
@@ -38,7 +38,7 @@ public function buildForm(array $form, FormStateInterface $form_state, $entity_t
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     $form_state->setValueForElement($form['id'], $this->targetEntityTypeId . '.' . $form_state->getValue('id'));
diff --git a/core/modules/filter/src/FilterFormatFormBase.php b/core/modules/filter/src/FilterFormatFormBase.php
index c370279..11c4501 100644
--- a/core/modules/filter/src/FilterFormatFormBase.php
+++ b/core/modules/filter/src/FilterFormatFormBase.php
@@ -204,7 +204,7 @@ public function exists($format_id) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     // @todo Move trimming upstream.
diff --git a/core/modules/node/src/NodeForm.php b/core/modules/node/src/NodeForm.php
index 92e7c0c..548bd5b 100644
--- a/core/modules/node/src/NodeForm.php
+++ b/core/modules/node/src/NodeForm.php
@@ -291,7 +291,7 @@ protected function actions(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     $node = parent::validate($form, $form_state);
 
     if ($node->id() && (node_last_changed($node->id(), $this->getFormLangcode($form_state)) > $node->getChangedTime())) {
diff --git a/core/modules/node/src/NodeTypeForm.php b/core/modules/node/src/NodeTypeForm.php
index b5c4674..d106dad 100644
--- a/core/modules/node/src/NodeTypeForm.php
+++ b/core/modules/node/src/NodeTypeForm.php
@@ -204,7 +204,7 @@ protected function actions(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     $id = trim($form_state->getValue('type'));
diff --git a/core/modules/responsive_image/src/ResponsiveImageStyleForm.php b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
index 365f7a5..ec6992f 100644
--- a/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
+++ b/core/modules/responsive_image/src/ResponsiveImageStyleForm.php
@@ -133,7 +133,7 @@ public function form(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     // Only validate on edit.
     if ($form_state->hasValue('keyed_styles')) {
       // Check if another breakpoint group is selected.
diff --git a/core/modules/search/src/Form/SearchPageFormBase.php b/core/modules/search/src/Form/SearchPageFormBase.php
index 95afb4b..02e95ca 100644
--- a/core/modules/search/src/Form/SearchPageFormBase.php
+++ b/core/modules/search/src/Form/SearchPageFormBase.php
@@ -144,7 +144,7 @@ public function exists($id) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     // Ensure each path is unique.
diff --git a/core/modules/system/src/Form/DateFormatFormBase.php b/core/modules/system/src/Form/DateFormatFormBase.php
index c843ba2..bece243 100644
--- a/core/modules/system/src/Form/DateFormatFormBase.php
+++ b/core/modules/system/src/Form/DateFormatFormBase.php
@@ -155,7 +155,7 @@ public function form(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     // The machine name field should already check to see if the requested
diff --git a/core/modules/taxonomy/src/TermForm.php b/core/modules/taxonomy/src/TermForm.php
index daa2868..b7116cb 100644
--- a/core/modules/taxonomy/src/TermForm.php
+++ b/core/modules/taxonomy/src/TermForm.php
@@ -94,7 +94,7 @@ public function form(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     // Ensure numeric values.
diff --git a/core/modules/user/src/AccountForm.php b/core/modules/user/src/AccountForm.php
index 8c14682..540120c 100644
--- a/core/modules/user/src/AccountForm.php
+++ b/core/modules/user/src/AccountForm.php
@@ -40,6 +40,13 @@
   protected $entityQuery;
 
   /**
+   * The entity being used by this form.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $entity;
+
+  /**
    * Constructs a new EntityForm object.
    *
    * @param \Drupal\Core\Entity\EntityManagerInterface $entity_manager
@@ -70,7 +77,6 @@ public static function create(ContainerInterface $container) {
    * {@inheritdoc}
    */
   public function form(array $form, FormStateInterface $form_state) {
-    /** @var \Drupal\user\UserInterface $account */
     $account = $this->entity;
     $user = $this->currentUser();
     $config = \Drupal::config('user.settings');
@@ -173,7 +179,6 @@ public function form(array $form, FormStateInterface $form_state) {
         );
 
         $form_state->set('user', $account);
-        $form['#validate'][] = 'user_validate_current_pass';
       }
     }
     elseif (!$config->get('verify_mail') || $admin) {
@@ -333,6 +338,17 @@ public function alterPreferredLangcodeDescription(array $element) {
   }
 
   /**
+   * {@inheritdoc}
+   */
+  protected function actions(array $form, FormStateInterface $form_state) {
+    $actions = parent::actions($form, $form_state);
+    if (!$this->entity->isAnonymous() && $this->currentUser()->id() == $this->entity->id()) {
+      $actions['submit']['#validate'][] = 'user_validate_current_pass';
+    }
+    return $actions;
+  }
+
+  /**
    * Synchronizes preferred language and entity language.
    *
    * @param string $entity_type_id
@@ -383,7 +399,7 @@ public function buildEntity(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     /** @var \Drupal\user\UserInterface $account */
     $account = parent::validate($form, $form_state);
 
diff --git a/core/modules/views_ui/src/ViewAddForm.php b/core/modules/views_ui/src/ViewAddForm.php
index 9750094..91dcf50 100644
--- a/core/modules/views_ui/src/ViewAddForm.php
+++ b/core/modules/views_ui/src/ViewAddForm.php
@@ -162,7 +162,7 @@ protected function actions(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     $wizard_type = $form_state->getValue(array('show', 'wizard_key'));
     $wizard_instance = $this->wizardManager->createInstance($wizard_type);
     $form_state->set('wizard', $wizard_instance->getPluginDefinition());
diff --git a/core/modules/views_ui/src/ViewEditForm.php b/core/modules/views_ui/src/ViewEditForm.php
index 1205f28..ca38ed0 100644
--- a/core/modules/views_ui/src/ViewEditForm.php
+++ b/core/modules/views_ui/src/ViewEditForm.php
@@ -246,7 +246,7 @@ protected function actions(array $form, FormStateInterface $form_state) {
   /**
    * {@inheritdoc}
    */
-  public function validate(array $form, FormStateInterface $form_state) {
+  public function validate(array &$form, FormStateInterface $form_state) {
     parent::validate($form, $form_state);
 
     $view = $this->entity;