diff --git a/core/lib/Drupal/Core/Entity/Field/FieldDefinition.php b/core/lib/Drupal/Core/Entity/Field/FieldDefinition.php
index 0c40c42..03955a2 100644
--- a/core/lib/Drupal/Core/Entity/Field/FieldDefinition.php
+++ b/core/lib/Drupal/Core/Entity/Field/FieldDefinition.php
@@ -283,20 +283,17 @@ public static function createFromOldStyleDefinition(array $definition) {
         $field_definition->setClass($type_definition['list_class']);
       }
     }
-
-    // Take care of the item definition now. 'required' applies to the list
-    // definition.
-    unset($definition['required']);
-    $item_definition = new DataDefinition($definition);
-    if (isset($definition['settings'])) {
-      $item_definition->setSettings($definition['settings']);
-    }
-    if (isset($definition['constraints'])) {
-      $item_definition->setConstraints($definition['constraints']);
-    }
-    if (isset($definition['translatable']) && $definition['translatable']) {
+    if (isset($definition['translatable'])) {
       $field_definition->setTranslatable($definition['translatable']);
+      unset($definition['translatable']);
     }
+    if (isset($definition['required'])) {
+      $field_definition->setRequired($definition['required']);
+      unset($definition['required']);
+    }
+
+    // Take care of the item definition now.
+    $item_definition = new DataDefinition($definition);
     $field_definition->setItemDefinition($item_definition);
     return $field_definition;
   }
diff --git a/core/lib/Drupal/Core/TypedData/DataDefinition.php b/core/lib/Drupal/Core/TypedData/DataDefinition.php
index 7bf7ea8..1d96693 100644
--- a/core/lib/Drupal/Core/TypedData/DataDefinition.php
+++ b/core/lib/Drupal/Core/TypedData/DataDefinition.php
@@ -169,7 +169,7 @@ public function isRequired() {
    * @param bool $required
    *   Whether the data is required.
    *
-   * @return \Drupal\Core\TypedData\DataDefinition
+   * @return \Drupal\Core\TypedData\DataDefinitionInterface
    *   The object itself for chaining.
    */
   public function setRequired($required) {
@@ -190,7 +190,7 @@ public function getClass() {
    * @param string|null $class
    *   The class to use.
    *
-   * @return \Drupal\Core\TypedData\DataDefinition
+   * @return \Drupal\Core\TypedData\DataDefinitionInterface
    *   The object itself for chaining.
    */
   public function setClass($class) {
@@ -216,7 +216,7 @@ public function getSettings() {
    * @param array $settings
    *   The array of settings.
    *
-   * @return \Drupal\Core\TypedData\DataDefinition
+   * @return \Drupal\Core\TypedData\DataDefinitionInterface
    *   The object itself for chaining.
    */
   public function setSettings(array $settings) {
@@ -245,7 +245,7 @@ public function getConstraints() {
    * @param array $constraints
    *   The array of constraints.
    *
-   * @return \Drupal\Core\TypedData\DataDefinition
+   * @return \Drupal\Core\TypedData\DataDefinitionInterface
    *   The object itself for chaining.
    */
   public function setConstraints(array $constraints) {
@@ -316,7 +316,7 @@ public function toArray() {
   /**
    * Allows creating data definition objects from old style definition arrays.
    *
-   * @todo: Remove once no old-style definition arrays need to be supported.
+   * @todo: Remove once https://drupal.org/node/2112239 is in.
    */
   public static function createFromOldStyleDefinition(array $definition) {
     if (empty($definition['list'])) {
@@ -345,17 +345,14 @@ public static function createFromOldStyleDefinition(array $definition) {
         $list_definition->setClass($type_definition['list_class']);
       }
     }
+    if (isset($definition['required'])) {
+      $$list_definition->setRequired($definition['required']);
+      unset($definition['required']);
+    }
 
-    // Take care of the item definition now. 'required' applies to the list
-    // definition.
+    // Take care of the item definition now.
     unset($definition['required']);
     $item_definition = new DataDefinition($definition);
-    if (isset($definition['settings'])) {
-      $item_definition->setSettings($definition['settings']);
-    }
-    if (isset($definition['constraints'])) {
-      $item_definition->setConstraints($definition['constraints']);
-    }
     $list_definition->setItemDefinition($item_definition);
     return $list_definition;
   }
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataManager.php b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
index 0cb1e8e..7e30812 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataManager.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataManager.php
@@ -78,7 +78,7 @@ public function createInstance($data_type, array $configuration) {
     }
 
     // Allow per-data definition overrides of the used classes, i.e. take over
-    // classes specified in the data definition.
+    // classes specified in the type definition.
     $class = $data_definition->getClass();
     $class = isset($class) ? $class : $type_definition['class'];
 
@@ -121,6 +121,7 @@ public function createInstance($data_type, array $configuration) {
    * @see \Drupal\Core\TypedData\Plugin\DataType\Binary
    */
   public function create($definition, $value = NULL, $name = NULL, $parent = NULL) {
+    // @todo: Remove array support once https://drupal.org/node/2112239 is in.
     if (is_array($definition)) {
       $definition = DataDefinition::createFromOldStyleDefinition($definition);
     }