diff --git a/core/lib/Drupal/Core/TypedData/Type/Date.php b/core/lib/Drupal/Core/TypedData/Type/Date.php
index 37a55ff..e326674 100644
--- a/core/lib/Drupal/Core/TypedData/Type/Date.php
+++ b/core/lib/Drupal/Core/TypedData/Type/Date.php
@@ -42,11 +42,4 @@ public function setValue($value) {
       $this->value = $value instanceOf DrupalDateTime ? $value : new DrupalDateTime($value);
     }
   }
-
-  /**
-   * Overrides TypedDataInterface::getString().
-   */
-  public function getString() {
-    return (string) $this->getValue();
-  }
 }
diff --git a/core/lib/Drupal/Core/TypedData/Type/Duration.php b/core/lib/Drupal/Core/TypedData/Type/Duration.php
index 985d38d..fa539cf 100644
--- a/core/lib/Drupal/Core/TypedData/Type/Duration.php
+++ b/core/lib/Drupal/Core/TypedData/Type/Duration.php
@@ -32,6 +32,7 @@ class Duration extends TypedData {
    * Overrides TypedData::setValue().
    */
   public function setValue($value) {
+    // Catch any exceptions thrown due to invalid values being passed.
     try {
       if ($value instanceof DateInterval || !isset($value)) {
         $this->value = $value;
diff --git a/core/lib/Drupal/Core/Validation/ConstraintManager.php b/core/lib/Drupal/Core/Validation/ConstraintManager.php
index eb25001..5177f09 100644
--- a/core/lib/Drupal/Core/Validation/ConstraintManager.php
+++ b/core/lib/Drupal/Core/Validation/ConstraintManager.php
@@ -47,8 +47,6 @@ public function __construct() {
     $this->discovery = new AlterDecorator($this->discovery, 'validation_constraint');
     $this->discovery = new CacheDecorator($this->discovery, 'validation_constraints:' . language(LANGUAGE_TYPE_INTERFACE)->langcode);
 
-    // We overrode getDefinition() and getDefinitions() so we must pass the
-    // PluginManager and not just discovery.
     $this->factory = new DefaultFactory($this);
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
index 5f93835..6b10de6 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
@@ -335,7 +335,7 @@ protected function assertIntrospection($entity_type) {
       'constraints' => array(
         'EntityType' => $entity_type,
       ),
-      'label' => t('Test entity'),
+      'label' => 'Test entity',
     );
     $wrapped_entity = typed_data()->create($definition);
     $definitions = $wrapped_entity->getPropertyDefinitions($definition);
@@ -455,7 +455,7 @@ protected function assertDataStructureInterfaces($entity_type) {
       'constraints' => array(
         'EntityType' => $entity_type,
       ),
-      'label' => t('Test entity'),
+      'label' => 'Test entity',
     );
     $wrapped_entity = typed_data()->create($entity_definition, $entity);
 
@@ -514,7 +514,7 @@ public function testEntityConstraintValidation() {
       'constraints' => array(
         'EntityType' => 'entity_test',
       ),
-      'label' => t('Test entity'),
+      'label' => 'Test entity',
     );
     $wrapped_entity = typed_data()->create($entity_definition, $entity);
 
@@ -535,7 +535,7 @@ public function testEntityConstraintValidation() {
         'EntityType' => 'node',
         'Bundle' => 'article',
       ),
-      'label' => t('Test entity'),
+      'label' => 'Test node',
     );
     $wrapped_entity = typed_data()->create($entity_definition, $node);
 
@@ -543,7 +543,7 @@ public function testEntityConstraintValidation() {
     $this->assertEqual($violations->count(), 1);
 
     $node->type = 'article';
-    node_save($node);
+    $node->save();
     $wrapped_entity->setValue($node);
     $violations = $wrapped_entity->validate();
     $this->assertEqual($violations->count(), 0);
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index 6c69294..2c97b0a 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -176,6 +176,7 @@ function hook_data_type_info() {
       'label' => t('Email'),
       'class' => '\Drupal\email\Type\Email',
       'primitive type' => \Drupal\Core\TypedData\Primitive::String,
+      'constraints' => array('Email' => array()),
     ),
   );
 }