diff --git a/core/lib/Drupal/Core/Entity/EntityBCDecorator.php b/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
index 5f6d481..448d434 100644
--- a/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
+++ b/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
@@ -124,7 +124,6 @@ public function &__get($name) {
         $this->decorated->values[$name][Language::LANGCODE_DEFAULT][0]['value'] = NULL;
       }
       if (is_array($this->decorated->values[$name][Language::LANGCODE_DEFAULT])) {
-        // This will work with all defined properties that have a single value.
         // We need to ensure the key doesn't matter. Mostly it's 'value' but
         // e.g. EntityReferenceItem uses target_id - so just take the first one.
         if (isset($this->decorated->values[$name][Language::LANGCODE_DEFAULT][0]) && is_array($this->decorated->values[$name][Language::LANGCODE_DEFAULT][0])) {
diff --git a/core/lib/Drupal/Core/Entity/EntityFormController.php b/core/lib/Drupal/Core/Entity/EntityFormController.php
index ab00b90..4c3e113 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormController.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormController.php
@@ -256,7 +256,7 @@ public function validate(array $form, array &$form_state) {
     }
     else {
       // For BC entities, iterate through each field instance and
-      // instanciate NG items objects manually.
+      // instantiate NG items objects manually.
       $definitions = \Drupal::entityManager()->getFieldDefinitions($entity->entityType(), $entity->bundle());
       foreach (field_info_instances($entity->entityType(), $entity->bundle()) as $field_name => $instance) {
         $langcode = field_is_translatable($entity->entityType(), $instance->getField()) ? $entity_langcode : Language::LANGCODE_NOT_SPECIFIED;
diff --git a/core/lib/Drupal/Core/Entity/EntityStorageControllerBase.php b/core/lib/Drupal/Core/Entity/EntityStorageControllerBase.php
index 5aeea36..3dd7983 100644
--- a/core/lib/Drupal/Core/Entity/EntityStorageControllerBase.php
+++ b/core/lib/Drupal/Core/Entity/EntityStorageControllerBase.php
@@ -150,7 +150,7 @@ public function invokeFieldMethod($method, EntityInterface $entity) {
         }
       }
       else {
-        // For BC entities, iterate through fields and instanciate NG items
+        // For BC entities, iterate through fields and instantiate NG items
         // objects manually.
         $definitions = \Drupal::entityManager()->getFieldDefinitions($entity->entityType(), $entity->bundle());
         foreach ($definitions as $field_name => $definition) {
@@ -244,7 +244,7 @@ public function invokeFieldItemPrepareCache(EntityInterface $entity) {
         foreach ($translation->getPropertyDefinitions() as $property => $definition) {
           $type_definition = \Drupal::typedData()->getDefinition($definition['type']);
           // Only create the item objects if needed.
-          if (is_subclass_of($type_definition['class'], '\Drupal\field\Plugin\Type\FieldType\PrepareCacheInterface')
+          if (is_subclass_of($type_definition['class'], '\Drupal\Core\Entity\Field\PrepareCacheInterface')
             // Prevent legacy field types from skewing performance too much by
             // checking the existence of the legacy function directly, instead
             // of making LegacyConfigFieldItem implement PrepareCacheInterface.
@@ -261,14 +261,14 @@ public function invokeFieldItemPrepareCache(EntityInterface $entity) {
         }
       }
       else {
-        // For BC entities, iterate through the fields and instanciate NG items
+        // For BC entities, iterate through the fields and instantiate NG items
         // objects manually.
         $definitions = \Drupal::entityManager()->getFieldDefinitions($entity->entityType(), $entity->bundle());
         foreach ($definitions as $field_name => $definition) {
           if (!empty($definition['configurable'])) {
             $type_definition = \Drupal::typedData()->getDefinition($definition['type']);
             // Only create the item objects if needed.
-            if (is_subclass_of($type_definition['class'], '\Drupal\field\Plugin\Type\FieldType\PrepareCacheInterface')
+            if (is_subclass_of($type_definition['class'], '\Drupal\Core\Entity\Field\PrepareCacheInterface')
               // @todo Remove once all core field types have been converted
               // (see http://drupal.org/node/2014671).
               || (is_subclass_of($type_definition['class'], '\Drupal\field\Plugin\field\field_type\LegacyConfigFieldItem') && function_exists($type_definition['module'] . '_field_load'))) {
diff --git a/core/lib/Drupal/Core/Entity/Field/PrepareCacheInterface.php b/core/lib/Drupal/Core/Entity/Field/PrepareCacheInterface.php
new file mode 100644
index 0000000..5701523
--- /dev/null
+++ b/core/lib/Drupal/Core/Entity/Field/PrepareCacheInterface.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Entity\Field\PrepareCacheInterface.
+ */
+
+namespace Drupal\Core\Entity\Field;
+
+/**
+ * Interface for preparing field values before they enter cache.
+ *
+ * If a field type implements this interface, the prepareCache() method will be
+ * invoked before field values get cached.
+ */
+interface PrepareCacheInterface {
+
+  /**
+   * Massages loaded field values before they enter the field cache.
+   *
+   * You should never load fieldable entities within this method, since this is
+   * likely to cause infinite recursions. Use the prepareView() method instead.
+   *
+   * Also note that the method is not called on field values displayed during
+   * entity preview. If the method adds elements that might be needed during
+   * display, you might want to also use prepareView() to add those elements in
+   * case they are not present.
+   */
+  public function prepareCache();
+
+}
diff --git a/core/lib/Drupal/Core/Entity/Plugin/DataType/FieldDataTypeDerivative.php b/core/lib/Drupal/Core/Entity/Plugin/DataType/FieldDataTypeDerivative.php
index 5591e74..504e427 100644
--- a/core/lib/Drupal/Core/Entity/Plugin/DataType/FieldDataTypeDerivative.php
+++ b/core/lib/Drupal/Core/Entity/Plugin/DataType/FieldDataTypeDerivative.php
@@ -10,7 +10,7 @@
 use Drupal\Component\Plugin\Derivative\DerivativeInterface;
 
 /**
- * Provides data type plugins for each existing "configurable field" plugin.
+ * Provides data type plugins for each existing field type plugin.
  */
 class FieldDataTypeDerivative implements DerivativeInterface {
 
diff --git a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/CountConstraint.php b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/CountConstraint.php
index 5a343f5..d44ff6b 100644
--- a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/CountConstraint.php
+++ b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/CountConstraint.php
@@ -29,7 +29,7 @@ class CountConstraint extends Count {
   public $exactMessage = 'This collection should contain exactly %limit element.|This collection should contain exactly %limit elements.';
 
   /**
-   * Overrides Range::validatedBy().
+   * {@inheritdoc}
    */
   public function validatedBy() {
     return '\Symfony\Component\Validator\Constraints\CountValidator';
diff --git a/core/modules/field/field.attach.inc b/core/modules/field/field.attach.inc
index 699d687..fc101e0 100644
--- a/core/modules/field/field.attach.inc
+++ b/core/modules/field/field.attach.inc
@@ -560,7 +560,7 @@ function field_attach_form(EntityInterface $entity, &$form, &$form_state, $langc
  * @param $options
  *   An associative array of additional options, with the following keys:
  *   - instance: A field instance entity, If provided, only values for the
- *     corresponding field will be loaded, and the cache is bypassed. This
+ *     corresponding field will be loaded, and no cache is written. This
  *     option is only supported when all $entities are within the same bundle.
  */
 function field_attach_load($entity_type, $entities, $age = FIELD_LOAD_CURRENT, $options = array()) {
diff --git a/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/Field.php b/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/Field.php
index 1d207fc..c2fe6c0 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/Field.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/Core/Entity/Field.php
@@ -194,13 +194,6 @@ class Field extends ConfigEntityBase implements FieldInterface {
   public $deleted = FALSE;
 
   /**
-   * The field type handler.
-   *
-   * @var \Drupal\field\Plugin\Type\FieldType\ConfigFieldItemInterface
-   */
-  protected $handler;
-
-  /**
    * The field schema.
    *
    * @var array
diff --git a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigEntityReferenceItemBase.php b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigEntityReferenceItemBase.php
index 1dadc77..4535159 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigEntityReferenceItemBase.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigEntityReferenceItemBase.php
@@ -111,6 +111,7 @@ public function isEmpty() {
     if (!empty($target_id) && is_numeric($target_id)) {
       return FALSE;
     }
+    // Allow auto-create entities.
     if (empty($target_id) && ($entity = $this->get('entity')->getValue()) && $entity->isNew()) {
       return FALSE;
     }
diff --git a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigFieldItemInterface.php b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigFieldItemInterface.php
index 883e499..1a8a8e0 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigFieldItemInterface.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/ConfigFieldItemInterface.php
@@ -27,7 +27,7 @@ public function getInstance();
    *
    * This method is static, because the field schema information is needed on
    * creation of the field. No field instances exist by then, and it is not
-   * possible to instanciate a FieldItemInterface object yet.
+   * possible to instantiate a FieldItemInterface object yet.
    *
    * @param \Drupal\field\Plugin\Core\Entity\Field $field
    *   The field definition.
diff --git a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/PrepareCacheInterface.php b/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/PrepareCacheInterface.php
deleted file mode 100644
index 6aadec1..0000000
--- a/core/modules/field/lib/Drupal/field/Plugin/Type/FieldType/PrepareCacheInterface.php
+++ /dev/null
@@ -1,30 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\field\Plugin\Type\FieldType\PrepareCacheInterface.
- */
-
-namespace Drupal\field\Plugin\Type\FieldType;
-
-use Drupal\field\Plugin\Type\FieldType\ConfigFieldItemInterface;
-
-/**
- * Interface definition for "Field type" plugins.
- */
-interface PrepareCacheInterface extends ConfigFieldItemInterface {
-
-  /**
-   * Massages loaded field values before they enter the field cache.
-   *
-   * You should never load fieldable entities within this method, since this is
-   * likely to cause infinite recursions. Use the prepareView() method instead.
-   *
-   * Also note that the method is not called on field values displayed during
-   * entity preview. If the method adds elements that might be needed during
-   * display, you might want to also use prepareView() to add those elements in
-   * case they are not present.
-   */
-  public function prepareCache();
-
-}
diff --git a/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php b/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php
index ea9425b..d965401 100644
--- a/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php
+++ b/core/modules/field/lib/Drupal/field/Plugin/field/field_type/LegacyConfigFieldItem.php
@@ -76,8 +76,8 @@ public function instanceSettingsForm(array $form, array &$form_state) {
   /**
    * Massages loaded field values before they enter the field cache.
    *
-   * This impelments the prepareCache() method defined in PrepareCacheInterface
-   * even if the class does explicitly implements its, so as to preserve
+   * This implements the prepareCache() method defined in PrepareCacheInterface
+   * even if the class does explicitly implements it, so as to preserve
    * the optimizations of only creating Field and FieldItem objects and invoking
    * the method if are actually needed.
    *
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
index 37eaf19..36d5d1d 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
@@ -135,7 +135,7 @@ public function buildForm(array $form, array &$form_state, FieldInstanceInterfac
     $form['field']['settings'] = array(
       '#weight' => 10,
     );
-    // Create an arbitrary entity object, so that we can have an instanciated
+    // Create an arbitrary entity object, so that we can have an instantiated
     // FieldItem.
     $ids = (object) array('entity_type' => $this->instance['entity_type'], 'bundle' => $this->instance['bundle'], 'entity_id' => NULL);
     $entity = _field_create_entity_from_ids($ids);
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
index f8af209..16ab117 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php
@@ -149,7 +149,7 @@ public function validateForm(array &$form, array &$form_state) {
         $itemsNG = $entity->{$field_name};
       }
       else {
-        // For BC entities, instanciate NG items objects manually.
+        // For BC entities, instantiate NG items objects manually.
         $definitions = \Drupal::entityManager()->getFieldDefinitions($entity->entityType(), $entity->bundle());
         $itemsNG = \Drupal::typedData()->create($definitions[$field_name], $items, $field_name, $entity);
       }
diff --git a/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextItemBase.php b/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextItemBase.php
index 15edc00..17f2ba3 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextItemBase.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextItemBase.php
@@ -8,7 +8,7 @@
 namespace Drupal\text\Plugin\field\field_type;
 
 use Drupal\field\Plugin\Type\FieldType\ConfigFieldItemBase;
-use Drupal\field\Plugin\Type\FieldType\PrepareCacheInterface;
+use Drupal\Core\Entity\Field\PrepareCacheInterface;
 
 /**
  * Base class for 'text' configurable field types.
diff --git a/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextWithSummaryItem.php b/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextWithSummaryItem.php
index 900cf4a..4d9030d 100644
--- a/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextWithSummaryItem.php
+++ b/core/modules/text/lib/Drupal/text/Plugin/field/field_type/TextWithSummaryItem.php
@@ -113,7 +113,7 @@ public function getConstraints() {
     if (!empty($this->getInstance()->getField()->settings['max_length'])) {
       $max_length = $this->getInstance()->getField()->settings['max_length'];
       $constraints[] = $constraint_manager->create('ComplexData', array(
-        'value' => array(
+        'summary' => array(
           'Length' => array(
             'max' => $max_length,
             'maxMessage' => t('%name: the summary may not be longer than @max characters.', array('%name' => $this->getInstance()->label, '@max' => $max_length)),