core/includes/common.inc                           |   20 +++++++++++-
 .../tests/modules/common_test/common_test.module   |   34 ++++++++------------
 2 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/core/includes/common.inc b/core/includes/common.inc
index 2e28710..b553d6c 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -4275,11 +4275,29 @@ function _drupal_render_process_post_render_cache(array &$elements) {
     $modified_elements = $elements;
     foreach ($elements['#post_render_cache'] as $callback => $options) {
       foreach ($elements['#post_render_cache'][$callback] as $token => $context) {
+        // The advanced option, when setting #post_render_cache directly.
         if (is_numeric($token)) {
           $modified_elements = call_user_func_array($callback, array($modified_elements, $context));
         }
+        // The simple option, when using the standard placeholders, and hence
+        // also when using #type => render_cache_placeholder.
         else {
-          $modified_elements = call_user_func_array($callback, array($modified_elements, $context, $token));
+          // Call #post_render_cache callback to generate the element that will
+          // fill in the placeholder.
+          $generated_element = call_user_func_array($callback, array($context));
+
+          // Update #attached based on the generated element.
+          if (isset($generated_element['#attached'])) {
+            if (!isset($modified_elements['#attached'])) {
+              $modified_elements['#attached'] = array();
+            }
+            $modified_elements['#attached'] = drupal_merge_attached($modified_elements['#attached'], drupal_render_collect_attached($generated_element, TRUE));
+          }
+
+          // Replace the placeholder with the rendered markup of the generated
+          // element.
+          $placeholder = drupal_render_cache_generate_placeholder($callback, $context, $token);
+          $modified_elements['#markup'] = str_replace($placeholder, drupal_render($generated_element), $modified_elements['#markup']);
         }
       }
     }
diff --git a/core/modules/system/tests/modules/common_test/common_test.module b/core/modules/system/tests/modules/common_test/common_test.module
index cae051c..b3b8ad8 100644
--- a/core/modules/system/tests/modules/common_test/common_test.module
+++ b/core/modules/system/tests/modules/common_test/common_test.module
@@ -233,31 +233,25 @@ function common_test_post_render_cache(array $element, array $context) {
 /**
  * #post_render_cache callback; replaces placeholder, extends #attached.
  *
- * @param array $element
- *  A render array with the following keys:
- *    - #markup
- *    - #attached
  * @param array $context
  *  An array with the following keys:
  *    - bar: contains a random string.
- * @param string $token
- *   A unique token to uniquely identify the placeholder.
  *
- * @return array $element
- *   The updated $element.
+ * @return array
+ *   A render array.
  */
-function common_test_post_render_cache_placeholder(array $element, array $context, $token) {
-  // Generate exact placeholder string.
-  $placeholder = drupal_render_cache_generate_placeholder(__FUNCTION__, $context, $token);
-
-  // Replace placeholder in markup.
-  $element['#markup'] = str_replace($placeholder, '<bar>' . $context['bar'] . '</bar>', $element['#markup']);
-
-  // Extend #attached.
-  $element['#attached']['js'][] = array(
-    'type' => 'setting',
-    'data' => array(
-      'common_test' => $context
+function common_test_post_render_cache_placeholder(array $context) {
+  $element = array(
+    '#markup' => '<bar>' . $context['bar'] . '</bar>',
+    '#attached' => array(
+      'js' => array(
+        array(
+          'type' => 'setting',
+          'data' => array(
+            'common_test' => $context,
+          ),
+        ),
+      ),
     ),
   );