diff --git a/core/includes/common.inc b/core/includes/common.inc
index a4da21b..f5d1ff9 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -3633,7 +3633,7 @@ function drupal_render_cache_get(array $elements) {
  *
  * @see drupal_render_cache_get()
  */
-function drupal_render_cache_set(&$markup, array $elements) {
+function drupal_render_cache_set(&$markup, $elements) {
   // Create the cache ID for the element.
   if (!\Drupal::request()->isMethodSafe() || !$cid = drupal_render_cid_create($elements)) {
     return FALSE;
@@ -3729,7 +3729,7 @@ function drupal_render_cache_generate_placeholder($callback, array &$context) {
  * @see drupal_render()
  * @see drupal_render_collect_post_render_cache
  */
-function _drupal_render_process_post_render_cache(array &$elements) {
+function _drupal_render_process_post_render_cache(&$elements) {
   if (isset($elements['#post_render_cache'])) {
     /** @var \Drupal\Core\Controller\ControllerResolverInterface $controller_resolver */
     $controller_resolver = \Drupal::service('controller_resolver');
diff --git a/core/modules/system/src/Tests/Common/RenderTest.php b/core/modules/system/src/Tests/Common/RenderTest.php
index 7587af6..bf43051 100644
--- a/core/modules/system/src/Tests/Common/RenderTest.php
+++ b/core/modules/system/src/Tests/Common/RenderTest.php
@@ -11,6 +11,7 @@
 use Drupal\Component\Utility\Html;
 use Drupal\Core\Render\Element;
 use Drupal\simpletest\DrupalUnitTestBase;
+use Drupal\common_test\RenderableArray;
 
 /**
  * Tests drupal_render().
@@ -282,6 +283,40 @@ function testDrupalRenderBasics() {
   }
 
   /**
+   * Tests the output drupal_render() using objects instead of arrays.
+   */
+  function testDrupalRenderArrayObjects() {
+    // Simplest case, a single object.
+    $types[] = array(
+      'name' => 'Simple renderable object',
+      'value' => new RenderableArray(array('#markup' => 'Hello World')),
+      'expected' => 'Hello World',
+    );
+    // Two renderable objects
+    $types[] = array(
+      'name' => 'Array with two renderable objects',
+      'value' => array(
+          'hello' => new RenderableArray(array('#markup' => 'Hello', '#suffix' => ' ')),
+          'world' => new RenderableArray(array('#markup' => 'World')),
+       ),
+      'expected' => 'Hello World',
+    );
+    // More complex, mixed nested objects and arrays
+    $render = new RenderableArray();
+    $render['hello'] = new RenderableArray(array('#markup' => 'Hello', '#suffix' => ' '));
+    $render['world'] = array('#markup' => 'World');
+    $types[] = array(
+      'name' => 'Nested renderable objects',
+      'value' => $render,
+      'expected' => 'Hello World',
+    );
+    foreach($types as $type) {
+      $this->assertIdentical(drupal_render($type['value']), $type['expected'], '"' . $type['name'] . '" input rendered correctly by drupal_render().');
+    }
+  }
+
+
+  /**
    * Tests sorting by weight.
    */
   function testDrupalRenderSorting() {