Issue #2258355: Move hide and show to render/element class

Closes #2258355

core/includes/common.inc

@@ -348,14 +348,8 @@ function drupal_attach_tabledrag(&$element, array $options) {
 /**
  * Hides an element from later rendering.
  *
- * The first time render() or RenderInterface::render() is called on an element
- * tree, as each element in the tree is rendered, it is marked with a #printed
- * flag and the rendered children of the element are cached. Subsequent calls to
- * render() or RenderInterface::render() will not traverse the child tree of
- * this element again: they will just use the cached children. So if you want to
- * hide an element, be sure to call hide() on the element before its parent tree
- * is rendered for the first time, as it will have no effect on subsequent
- * renderings of the parent tree.
+ * Refer to Drupal\core\lib\Drupal\Core\Render\RendererInterface::render()
+ * for additional documentation.
  *
  * @param $element
  *   The element to be hidden.
@@ -363,11 +357,14 @@ function drupal_attach_tabledrag(&$element, array $options) {
  * @return array
  *   The element.
  *
- * @see \Drupal\Core\Render\RendererInterface
- * @see render()
- * @see show()
+ * @deprecated in drupal:10.1.0 and is removed from drupal:11.0.0. Use
+ *   to inline #printed=TRUE instead.
+ *
+ * @see https://www.drupal.org/node/3261271
+ * @see \Drupal\Core\Render\RendererInterface::render()
  */
 function hide(&$element) {
+  @trigger_error('The global hide() function is deprecated in drupal:10.1.0 and is removed from drupal:11.0.0. Use to inline #printed=TRUE instead. See https://www.drupal.org/node/3261271', E_USER_DEPRECATED);
   $element['#printed'] = TRUE;
   return $element;
 }
@@ -375,17 +372,8 @@ function hide(&$element) {
 /**
  * Shows a hidden element for later rendering.
  *
- * You can also use render($element), which shows the element while rendering
- * it.
- *
- * The first time render() or RenderInterface::render() is called on an element
- * tree, as each element in the tree is rendered, it is marked with a #printed
- * flag and the rendered children of the element are cached. Subsequent calls to
- * render() or RenderInterface::render() will not traverse the child tree of
- * this element again: they will just use the cached children. So if you want to
- * show an element, be sure to call show() on the element before its parent tree
- * is rendered for the first time, as it will have no effect on subsequent
- * renderings of the parent tree.
+ * Refer to Drupal\core\lib\Drupal\Core\Render\RendererInterface::render()
+ * for additional documentation.
  *
  * @param $element
  *   The element to be shown.
@@ -393,11 +381,14 @@ function hide(&$element) {
  * @return array
  *   The element.
  *
- * @see \Drupal\Core\Render\RendererInterface
- * @see render()
- * @see hide()
+ * @deprecated in drupal:10.1.0 and is removed from drupal:11.0.0. Use
+ *   to inline #printed=FALSE instead.
+ *
+ * @see https://www.drupal.org/node/3261271
+ * @see \Drupal\Core\Render\RendererInterface::render()
  */
 function show(&$element) {
+  @trigger_error('The global show() function is deprecated in drupal:10.1.0 and is removed from drupal:11.0.0. Use to inline #printed=FALSE instead. See https://www.drupal.org/node/3261271', E_USER_DEPRECATED);
   $element['#printed'] = FALSE;
   return $element;
 }