diff --git a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringWidget.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringTextfieldWidget.php
similarity index 89%
rename from core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringWidget.php
rename to core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringTextfieldWidget.php
index 853e661..0ed4239 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringWidget.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldWidget/StringTextfieldWidget.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\Core\Field\Plugin\Field\FieldWidget\StringWidget.
+ * Contains \Drupal\Core\Field\Plugin\Field\FieldWidget\StringTextfieldWidget.
  */
 
 namespace Drupal\Core\Field\Plugin\Field\FieldWidget;
@@ -12,17 +12,17 @@
 use Drupal\Core\Form\FormStateInterface;
 
 /**
- * Plugin implementation of the 'string' widget.
+ * Plugin implementation of the 'string_textfield' widget.
  *
  * @FieldWidget(
- *   id = "string",
- *   label = @Translation("String field"),
+ *   id = "string_textfield",
+ *   label = @Translation("Textfield"),
  *   field_types = {
  *     "string"
  *   }
  * )
  */
-class StringWidget extends WidgetBase {
+class StringTextfieldWidget extends WidgetBase {
 
   /**
    * {@inheritdoc}
diff --git a/core/modules/aggregator/src/Entity/Feed.php b/core/modules/aggregator/src/Entity/Feed.php
index d70ec7d..a0c36ef 100644
--- a/core/modules/aggregator/src/Entity/Feed.php
+++ b/core/modules/aggregator/src/Entity/Feed.php
@@ -145,7 +145,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setRequired(TRUE)
       ->setSetting('max_length', 255)
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => -5,
       ));
 
diff --git a/core/modules/block_content/src/Entity/BlockContent.php b/core/modules/block_content/src/Entity/BlockContent.php
index b004261..c870311 100644
--- a/core/modules/block_content/src/Entity/BlockContent.php
+++ b/core/modules/block_content/src/Entity/BlockContent.php
@@ -167,7 +167,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setTranslatable(TRUE)
       ->setRequired(TRUE)
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => -5,
       ))
       ->setDisplayConfigurable('form', TRUE);
diff --git a/core/modules/comment/src/Entity/Comment.php b/core/modules/comment/src/Entity/Comment.php
index edde6c3..6fe7c0d 100644
--- a/core/modules/comment/src/Entity/Comment.php
+++ b/core/modules/comment/src/Entity/Comment.php
@@ -229,7 +229,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setTranslatable(TRUE)
       ->setSetting('max_length', 64)
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         // Default comment body field has weight 20.
         'weight' => 10,
       ))
diff --git a/core/modules/comment/src/Tests/CommentTestBase.php b/core/modules/comment/src/Tests/CommentTestBase.php
index 05f139d..b4f6eda 100644
--- a/core/modules/comment/src/Tests/CommentTestBase.php
+++ b/core/modules/comment/src/Tests/CommentTestBase.php
@@ -218,7 +218,7 @@ public function setCommentSubject($enabled) {
     $form_display = entity_get_form_display('comment', 'comment', 'default');
     if ($enabled) {
       $form_display->setComponent('subject', array(
-        'type' => 'string',
+          'type' => 'string_textfield',
       ));
     }
     else {
diff --git a/core/modules/contact/src/Entity/Message.php b/core/modules/contact/src/Entity/Message.php
index 9cf50bc..1ff6624 100644
--- a/core/modules/contact/src/Entity/Message.php
+++ b/core/modules/contact/src/Entity/Message.php
@@ -162,7 +162,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setRequired(TRUE)
       ->setSetting('max_length', 100)
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => -10,
       ))
       ->setDisplayConfigurable('form', TRUE);
diff --git a/core/modules/content_translation/src/Tests/ContentTranslationTestBase.php b/core/modules/content_translation/src/Tests/ContentTranslationTestBase.php
index 881e71a..5fadb11 100644
--- a/core/modules/content_translation/src/Tests/ContentTranslationTestBase.php
+++ b/core/modules/content_translation/src/Tests/ContentTranslationTestBase.php
@@ -190,7 +190,7 @@ protected function setupTestFields() {
     ))->save();
     entity_get_form_display($this->entityTypeId, $this->bundle, 'default')
       ->setComponent($this->fieldName, array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => 0,
       ))
       ->save();
diff --git a/core/modules/field/src/Tests/String/StringFormatterTest.php b/core/modules/field/src/Tests/String/StringFormatterTest.php
index ea76e23..465b519 100644
--- a/core/modules/field/src/Tests/String/StringFormatterTest.php
+++ b/core/modules/field/src/Tests/String/StringFormatterTest.php
@@ -54,7 +54,7 @@ class StringFormatterTest extends KernelTestBase {
   /**
    * {@inheritdoc}
    */
-  function setUp() {
+  protected function setUp() {
     parent::setUp();
 
     // Configure the theme system.
@@ -105,9 +105,9 @@ protected function renderEntityFields(ContentEntityInterface $entity, EntityView
   }
 
   /**
-   * Tests text_plain formatter output.
+   * Tests string formatter output.
    */
-  function testPlainText() {
+  public function testStringFormatter() {
     $value = $this->randomString();
     $value .= "\n\n<strong>" . $this->randomString() . '</strong>';
     $value .= "\n\n" . $this->randomString();
diff --git a/core/modules/menu_link_content/src/Entity/MenuLinkContent.php b/core/modules/menu_link_content/src/Entity/MenuLinkContent.php
index 11f1d12..098c479 100644
--- a/core/modules/menu_link_content/src/Entity/MenuLinkContent.php
+++ b/core/modules/menu_link_content/src/Entity/MenuLinkContent.php
@@ -287,7 +287,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
         'weight' => -5,
       ))
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => -5,
       ))
       ->setDisplayConfigurable('form', TRUE);
@@ -306,7 +306,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
         'weight' => 0,
       ))
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => 0,
       ));
 
diff --git a/core/modules/node/src/Entity/Node.php b/core/modules/node/src/Entity/Node.php
index da0eb0b..8b254cf 100644
--- a/core/modules/node/src/Entity/Node.php
+++ b/core/modules/node/src/Entity/Node.php
@@ -365,7 +365,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
         'weight' => -5,
       ))
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => -5,
       ))
       ->setDisplayConfigurable('form', TRUE);
diff --git a/core/modules/shortcut/src/Entity/Shortcut.php b/core/modules/shortcut/src/Entity/Shortcut.php
index 706ef0a..ea15bf8 100644
--- a/core/modules/shortcut/src/Entity/Shortcut.php
+++ b/core/modules/shortcut/src/Entity/Shortcut.php
@@ -177,7 +177,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
       ->setDefaultValue('')
       ->setSetting('max_length', 255)
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => -10,
         'settings' => array(
           'size' => 40,
diff --git a/core/modules/taxonomy/src/Entity/Term.php b/core/modules/taxonomy/src/Entity/Term.php
index 51803c1..1a13008 100644
--- a/core/modules/taxonomy/src/Entity/Term.php
+++ b/core/modules/taxonomy/src/Entity/Term.php
@@ -133,7 +133,7 @@ public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
         'weight' => -5,
       ))
       ->setDisplayOptions('form', array(
-        'type' => 'string',
+        'type' => 'string_textfield',
         'weight' => -5,
       ))
       ->setDisplayConfigurable('form', TRUE);
diff --git a/core/modules/text/src/Plugin/Field/FieldWidget/TextfieldWidget.php b/core/modules/text/src/Plugin/Field/FieldWidget/TextfieldWidget.php
index 6bf39f8..ab2f19a 100644
--- a/core/modules/text/src/Plugin/Field/FieldWidget/TextfieldWidget.php
+++ b/core/modules/text/src/Plugin/Field/FieldWidget/TextfieldWidget.php
@@ -8,7 +8,7 @@
 namespace Drupal\text\Plugin\Field\FieldWidget;
 
 use Drupal\Core\Field\FieldItemListInterface;
-use Drupal\Core\Field\Plugin\Field\FieldWidget\StringWidget;
+use Drupal\Core\Field\Plugin\Field\FieldWidget\StringTextfieldWidget;
 use Drupal\Core\Form\FormStateInterface;
 use Symfony\Component\Validator\ConstraintViolationInterface;
 
@@ -19,12 +19,11 @@
  *   id = "text_textfield",
  *   label = @Translation("Text field"),
  *   field_types = {
- *     "text",
- *     "string"
+ *     "text"
  *   },
  * )
  */
-class TextfieldWidget extends StringWidget {
+class TextfieldWidget extends StringTextfieldWidget {
 
   /**
    * {@inheritdoc}
diff --git a/core/modules/text/src/Tests/Formatter/TextFormatterTest.php b/core/modules/text/src/Tests/Formatter/TextFormatterTest.php
index af55bd1..538928f 100644
--- a/core/modules/text/src/Tests/Formatter/TextFormatterTest.php
+++ b/core/modules/text/src/Tests/Formatter/TextFormatterTest.php
@@ -54,7 +54,6 @@ protected function setUp() {
       ),
     ))->save();
 
-    // Set up two fields: one with text processing enabled, the other disabled.
     entity_create('field_storage_config', array(
       'name' => 'processed_text',
       'entity_type' => $this->entityType,