core/modules/edit/lib/Drupal/edit/EditController.php |   17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/core/modules/edit/lib/Drupal/edit/EditController.php b/core/modules/edit/lib/Drupal/edit/EditController.php
index a242238..412c16a 100644
--- a/core/modules/edit/lib/Drupal/edit/EditController.php
+++ b/core/modules/edit/lib/Drupal/edit/EditController.php
@@ -235,8 +235,14 @@ public function fieldForm(EntityInterface $entity, $field_name, $langcode, $view
       $entity = $this->tempStoreFactory->get('edit')->get($entity->uuid());
 
       // Closure to render the field given a view mode.
-      $render_field_in_view_mode = function ($view_mode_id) use ($entity, $field_name, $langcode) {
-        return $this->renderField($entity, $field_name, $langcode, $view_mode_id);
+      // @todo Drupal 8 will — but does not yet — require PHP 5.4:
+      //       https://drupal.org/node/2152073. One of the new features in that
+      //       version is $this support for closures. See
+      //       http://php.net/manual/en/migration54.new-features.php.
+      //       That will allow us to get rid of this ugly $that = $this mess.
+      $that = $this;
+      $render_field_in_view_mode = function ($view_mode_id) use ($entity, $field_name, $langcode, $that) {
+        return $that->renderField($entity, $field_name, $langcode, $view_mode_id);
       };
 
       // Re-render the updated field.
@@ -294,8 +300,13 @@ public function fieldForm(EntityInterface $entity, $field_name, $langcode, $view
    *   Rendered HTML.
    *
    * @see hook_edit_render_field()
+   *
+   * @todo Until Drupal 8 requires PHP 5.4, we cannot call $this inside a
+   *       closure (see higher), which also means anything called from a closure
+   *       must be public. So, until https://drupal.org/node/2152073 lands, use
+   *       "public" instead of "protected".
    */
-  protected function renderField(EntityInterface $entity, $field_name, $langcode, $view_mode_id) {
+  public function renderField(EntityInterface $entity, $field_name, $langcode, $view_mode_id) {
     $entity_view_mode_ids = array_keys(entity_get_view_modes($entity->entityType()));
     if (in_array($view_mode_id, $entity_view_mode_ids)) {
       $output = field_view_field($entity, $field_name, $view_mode_id, $langcode);