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 ce78a40..b8df4b2 100644
--- a/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/StringItem.php
@@ -62,4 +62,25 @@ public static function schema(FieldDefinitionInterface $field_definition) {
     );
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getConstraints() {
+    $constraint_manager = \Drupal::typedDataManager()->getValidationConstraintManager();
+    $constraints = parent::getConstraints();
+
+    if ($max_length = $this->getFieldSetting('max_length')) {
+      $constraints[] = $constraint_manager->create('ComplexData', array(
+        'value' => array(
+          'Length' => array(
+            'max' => $max_length,
+            'maxMessage' => t('%name: the text may not be longer than @max characters.', array('%name' => $this->getFieldDefinition()->getLabel(), '@max' => $max_length)),
+          )
+        ),
+      ));
+    }
+
+    return $constraints;
+  }
+
 }
diff --git a/core/modules/field/field.module b/core/modules/field/field.module
index 5757bf3..e9c31e3 100644
--- a/core/modules/field/field.module
+++ b/core/modules/field/field.module
@@ -707,6 +707,7 @@ function field_hook_info() {
  * Implements hook_field_info_alter().
  */
 function field_field_info_alter(&$info) {
+  // Let core's field types to have formatters and widgets.
   $info['string']['default_formatter'] = 'text_plain';
   $info['integer']['default_formatter'] = 'text_plain';
 
diff --git a/core/modules/text/text.module b/core/modules/text/text.module
index 2e7497c..95a4326 100644
--- a/core/modules/text/text.module
+++ b/core/modules/text/text.module
@@ -194,8 +194,8 @@ function text_filter_format_disable($format) {
  * Implements hook_field_formatter_info_alter().
  */
 function text_field_formatter_info_alter(&$info) {
-  // Let a new field type re-use an existing formatter.
-  $info['text_plain']['field types'][] = 'text';
-  $info['text_plain']['field types'][] = 'text_long';
-  $info['text_plain']['field types'][] = 'text_with_summary';
+  // Let a new field types to re-use an existing formatter.
+  $info['text_plain']['field_types'][] = 'text';
+  $info['text_plain']['field_types'][] = 'text_long';
+  $info['text_plain']['field_types'][] = 'text_with_summary';
 }