diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/DurationIso8601.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/DurationIso8601.php
index 8afd4fb..d83261f 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/DurationIso8601.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/DurationIso8601.php
@@ -17,7 +17,7 @@
  * The plain value of this data type is a ISO8601 duration string.
  *
  * @DataType(
- *   id = "duration",
+ *   id = "duration_iso8601",
  *   label = @Translation("Duration")
  * )
  */
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Timestamp.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Timestamp.php
index eba1c6e..18c99dc 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Timestamp.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Timestamp.php
@@ -5,7 +5,7 @@
  * Contains \Drupal\Core\TypedData\Type\Timestamp.
  */
 
-namespace Drupal\Core\TypedData\Type;
+namespace Drupal\Core\TypedData\Plugin\DataType;
 
 use Drupal\Core\TypedData\Annotation\DataType;
 use Drupal\Core\Annotation\Translation;
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataManager.php b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
index 05f282d..2fe7891 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataManager.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\TypedData;
 
+use Drupal\Component\Plugin\Exception\PluginException;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Language\LanguageManager;
@@ -356,7 +357,7 @@ public function getConstraints($definition) {
     $validation_manager = $this->getValidationConstraintManager();
 
     $type_definition = $this->getDefinition($definition['type']);
-    // Auto-generate a constraint data types implementing a primitive interface.
+    // Auto-generate a constraint for data types implementing a primitive interface.
     if (is_subclass_of($type_definition['class'], '\Drupal\Core\TypedData\PrimitiveInterface')) {
       $constraints[] = $validation_manager->create('PrimitiveType', array());
     }