diff --git a/core/includes/common.inc b/core/includes/common.inc
index c3d5c9d..e52181d7 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -4469,6 +4469,10 @@ function drupal_sort_title($a, $b) {
 
 /**
  * Checks if the key is a property.
+ *
+ * @see \Drupal\Core\Render\Element::property()
+ *
+ * @deprecated as of Drupal 8.0. Use Element::property() instead.
  */
 function element_property($key) {
   return Element::property($key);
@@ -4476,6 +4480,10 @@ function element_property($key) {
 
 /**
  * Gets properties of a structured array element (keys beginning with '#').
+ *
+ * @see \Drupal\Core\Render\Element::properties()
+ *
+ * @deprecated as of Drupal 8.0. Use Element::properties() instead.
  */
 function element_properties($element) {
   return Element::properties($element);
@@ -4483,6 +4491,10 @@ function element_properties($element) {
 
 /**
  * Checks if the key is a child.
+ *
+ * @see \Drupal\Core\Render\Element::child()
+ *
+ * @deprecated as of Drupal 8.0. Use Element::child() instead.
  */
 function element_child($key) {
   return Element::child($key);
@@ -4501,6 +4513,10 @@ function element_child($key) {
  *
  * @return
  *   The array keys of the element's children.
+ *
+ * @see \Drupal\Core\Render\Element::children()
+ *
+ * @deprecated as of Drupal 8.0. Use Element::children() instead.
  */
 function element_children(&$elements, $sort = FALSE) {
   return Element::children($elements, $sort);
@@ -4514,6 +4530,10 @@ function element_children(&$elements, $sort = FALSE) {
  *
  * @return
  *   The array keys of the element's visible children.
+ *
+ * @see \Drupal\Core\Render\Element::getVisibleChildren()
+ *
+ * @deprecated as of Drupal 8.0. Use Element::getVisibleChildren() instead.
  */
 function element_get_visible_children(array $elements) {
   return Element::getVisibleChildren($elements);
@@ -4530,6 +4550,10 @@ function element_get_visible_children(array $elements) {
  *   array('#propertyname' => 'attributename'). If both names are identical
  *   except for the leading '#', then an attribute name value is sufficient and
  *   no property name needs to be specified.
+ *
+ * @see \Drupal\Core\Render\Element::setAttributes()
+ *
+ * @deprecated as of Drupal 8.0. Use Element::setAttributes() instead.
  */
 function element_set_attributes(array &$element, array $map) {
   Element::setAttributes($element, $map);
diff --git a/core/lib/Drupal/Core/Render/Element.php b/core/lib/Drupal/Core/Render/Element.php
index c3d2952..83a8f97 100644
--- a/core/lib/Drupal/Core/Render/Element.php
+++ b/core/lib/Drupal/Core/Render/Element.php
@@ -57,12 +57,13 @@ public static function child($key) {
    * The children of a element array are those key/value pairs whose key does
    * not start with a '#'. See drupal_render() for details.
    *
-   * @param $elements
-   *   The element array whose children are to be identified.
-   * @param $sort
+   * @param array $elements
+   *   The element array whose children are to be identified. Passed by
+   *   reference.
+   * @param bool $sort
    *   Boolean to indicate whether the children should be sorted by weight.
    *
-   * @return
+   * @return array
    *   The array keys of the element's children.
    */
   public static function children(array &$elements, $sort = FALSE) {
@@ -106,10 +107,10 @@ public static function children(array &$elements, $sort = FALSE) {
   /**
    * Returns the visible children of an element.
    *
-   * @param $elements
+   * @param array $elements
    *   The parent element.
    *
-   * @return
+   * @return array
    *   The array keys of the element's visible children.
    */
   public static function getVisibleChildren(array $elements) {
@@ -137,9 +138,9 @@ public static function getVisibleChildren(array $elements) {
   /**
    * Sets HTML attributes based on element properties.
    *
-   * @param $element
-   *   The renderable element to process.
-   * @param $map
+   * @param array $element
+   *   The renderable element to process. Passed by reference.
+   * @param array $map
    *   An associative array whose keys are element property names and whose values
    *   are the HTML attribute names to set for corresponding the property; e.g.,
    *   array('#propertyname' => 'attributename'). If both names are identical