diff --git a/core/lib/Drupal/Core/Render/RenderVariable.php b/core/lib/Drupal/Core/Render/RenderVariable.php
index f6c874a..0253166 100644
--- a/core/lib/Drupal/Core/Render/RenderVariable.php
+++ b/core/lib/Drupal/Core/Render/RenderVariable.php
@@ -1,27 +1,101 @@
 <?php
+
 /**
- * Created by PhpStorm.
- * User: alex
- * Date: 24/09/15
- * Time: 11:59
+ * @file
+ * Contains \Drupal\Core\Render\RenderVariable.
  */
 
 namespace Drupal\Core\Render;
 
-
 use Drupal\Component\Utility\SafeMarkup;
 
 class RenderVariable {
 
-  public static function prefix() {
+  /**
+   * Prefixes a render variable.
+   *
+   * @param string|\Drupal\Component\Utility\SafeStringInterface|array $thing
+   *   A render variable. Either a string, an object that is safe or a render
+   *   array.
+   * @param string|\Drupal\Component\Utility\SafeStringInterface...
+   *   Prefixes to add to the render variable. By default these will XSS admin
+   *   filtered.
+   *
+   * @return array
+   */
+  public static function prefix($thing) {
+    $args = func_get_args();
+    unset($args[0]);
+    if (empty($args)) {
+      throw new \InvalidArgumentException();
+    }
+    $output = $thing;
+    foreach (array_reverse($args) as $arg) {
+      $output = static::makeRenderArray($output);
+      $output['#prefix'] = $arg;
+    }
+    return $output;
+  }
 
+  /**
+   * Suffixes a render variable.
+   *
+   * @param string|\Drupal\Component\Utility\SafeStringInterface|array $thing
+   *   A render variable. Either a string, an object that is safe or a render
+   *   array.
+   * @param string|\Drupal\Component\Utility\SafeStringInterface...
+   *   Suffixes to add to the render variable. By default these will XSS admin
+   *   filtered.
+   *
+   * @return array
+   */
+  public static function suffix($thing) {
+    $args = func_get_args();
+    unset($args[0]);
+    if (empty($args)) {
+      throw new \InvalidArgumentException();
+    }
+    $output = $thing;
+    foreach ($args as $arg) {
+      $output = static::makeRenderArray($output);
+      $output['#suffix'] = $arg;
+    }
+    return $output;
   }
 
-  public static function suffix() {
+  /**
+   * Wraps a render variable.
+   *
+   * @param string|\Drupal\Component\Utility\SafeStringInterface|array $thing
+   *   A render variable. Either a string, an object that is safe or a render
+   *   array.
+   * @param string|\Drupal\Component\Utility\SafeStringInterface $prefix
+   *   Prefix to add to the render variable. By default this will XSS admin
+   *   filtered.
+   * @param string|\Drupal\Component\Utility\SafeStringInterface $suffix
+   *   Prefix to add to the render variable. By default this will XSS admin
+   *   filtered.
+   *
+   * @return array
+   */
 
+  public static function wrap($thing, $prefix, $suffix) {
+    $output = static::makeRenderArray($thing);
+    $output['#prefix'] = $prefix;
+    $output['#suffix'] = $suffix;
   }
 
-  public static function wrap($thing, $prefix, $suffix) {
+  /**
+   * Converts a render variable into a render array.
+   *
+   * @param string|\Drupal\Component\Utility\SafeStringInterface|array $thing
+   *   A render variable. Either a string, an object that is safe or a render
+   *   array.
+   *
+   * @return array
+   *   A render array.
+   */
+  protected static function makeRenderArray($thing) {
     if (!is_array($thing)) {
       if (SafeMarkup::isSafe($thing)) {
         $output = [
@@ -35,8 +109,11 @@ public static function wrap($thing, $prefix, $suffix) {
       }
     }
     else {
-
+      $output = [
+        $thing
+      ];
     }
-
+    return $output;
   }
+
 }
\ No newline at end of file
diff --git a/core/modules/entity_reference/src/Plugin/views/row/EntityReference.php b/core/modules/entity_reference/src/Plugin/views/row/EntityReference.php
index b4fb085..ff396a0 100644
--- a/core/modules/entity_reference/src/Plugin/views/row/EntityReference.php
+++ b/core/modules/entity_reference/src/Plugin/views/row/EntityReference.php
@@ -8,6 +8,7 @@
 namespace Drupal\entity_reference\Plugin\views\row;
 
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Render\RenderVariable;
 use Drupal\views\Plugin\views\row\Fields;
 
 /**
@@ -43,8 +44,7 @@ public function buildOptionsForm(&$form, FormStateInterface $form_state) {
     parent::buildOptionsForm($form, $form_state);
 
     // Expand the description of the 'Inline field' checkboxes.
-    // @todo hmmm...
-    $form['inline']['#description'] .= '<br />' . $this->t("<strong>Note:</strong> In 'Entity Reference' displays, all fields will be displayed inline unless an explicit selection of inline fields is made here." );
+    $form['inline']['#description'] = RenderVariable::suffix($form['inline']['#description'], '<br />', $this->t("<strong>Note:</strong> In 'Entity Reference' displays, all fields will be displayed inline unless an explicit selection of inline fields is made here."));
   }
 
   /**
diff --git a/core/modules/views/src/Plugin/views/argument_default/ArgumentDefaultPluginBase.php b/core/modules/views/src/Plugin/views/argument_default/ArgumentDefaultPluginBase.php
index 72a7a67..8a9c0d8 100644
--- a/core/modules/views/src/Plugin/views/argument_default/ArgumentDefaultPluginBase.php
+++ b/core/modules/views/src/Plugin/views/argument_default/ArgumentDefaultPluginBase.php
@@ -8,6 +8,7 @@
 namespace Drupal\views\Plugin\views\argument_default;
 
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Render\RenderVariable;
 use Drupal\views\ViewExecutable;
 use Drupal\views\Plugin\views\argument\ArgumentPluginBase;
 use Drupal\views\Plugin\views\PluginBase;
@@ -98,8 +99,7 @@ protected function checkAccess(&$form, $option_name) {
     if (!$this->access()) {
       $form[$option_name]['#disabled'] = TRUE;
       $form[$option_name]['#value'] = $form[$this->option_name]['#default_value'];
-      // @todo - hmmm what.
-      $form[$option_name]['#description'] .= ' <strong>' . $this->t('Note: you do not have permission to modify this. If you change the default filter type, this setting will be lost and you will NOT be able to get it back.') . '</strong>';
+      $form[$option_name]['#description'] = RenderVariable::suffix($form[$option_name]['#description'], ' <strong>', $this->t('Note: you do not have permission to modify this. If you change the default filter type, this setting will be lost and you will NOT be able to get it back.'), '</strong>');
     }
   }
 
diff --git a/core/modules/views/src/Plugin/views/argument_validator/ArgumentValidatorPluginBase.php b/core/modules/views/src/Plugin/views/argument_validator/ArgumentValidatorPluginBase.php
index f83da27..017f992 100644
--- a/core/modules/views/src/Plugin/views/argument_validator/ArgumentValidatorPluginBase.php
+++ b/core/modules/views/src/Plugin/views/argument_validator/ArgumentValidatorPluginBase.php
@@ -8,6 +8,7 @@
 namespace Drupal\views\Plugin\views\argument_validator;
 
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Render\RenderVariable;
 use Drupal\views\ViewExecutable;
 use Drupal\views\Plugin\views\argument\ArgumentPluginBase;
 use Drupal\views\Plugin\views\PluginBase;
@@ -94,7 +95,7 @@ protected function checkAccess(&$form, $option_name) {
       $form[$option_name]['#disabled'] = TRUE;
       $form[$option_name]['#value'] = $form[$this->option_name]['#default_value'];
       // @todo - hmmm what.
-      $form[$option_name]['#description'] .= ' <strong>' . $this->t('Note: you do not have permission to modify this. If you change the default filter type, this setting will be lost and you will NOT be able to get it back.') . '</strong>';
+      $form[$option_name]['#description'] = RenderVariable::suffix($form[$option_name]['#description'], '<strong>', $this->t('Note: you do not have permission to modify this. If you change the default filter type, this setting will be lost and you will NOT be able to get it back.'), '</strong>');
     }
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Render/RenderVariableTest.php b/core/tests/Drupal/Tests/Core/Render/RenderVariableTest.php
new file mode 100644
index 0000000..f58ffa6
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Render/RenderVariableTest.php
@@ -0,0 +1,68 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\Render\RenderVariableTest.
+ */
+
+namespace Drupal\Tests\Core\Render;
+
+use Drupal\Core\Render\RenderVariable;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Render\RenderVariable
+ * @group Render
+ */
+class RenderVariableTest extends RendererTestBase {
+
+  /**
+   * @covers ::prefix
+   *
+   * @dataProvider providerRenderVariablePrefix
+   */
+  public function testRenderVariablePrefix($expected, $variable, array $prefixes) {
+    $args = $prefixes;
+    array_unshift($args, $variable);
+    $build = call_user_func_array([RenderVariable::class, 'prefix'], $args);
+    $render_output = $this->renderer->renderRoot($build);
+    $this->assertEquals($expected, (string) $render_output);
+  }
+
+  /**
+   * @return array
+   */
+  public function providerRenderVariablePrefix() {
+    $data = [];
+    $data[] = ['test&lt;em&gt;blah&lt;/em&gt;', '<em>blah</em>', ['test']];
+    $data[] = ['1 2 &lt;em&gt;blah&lt;/em&gt;', '<em>blah</em>', ['1', ' ', '2', ' ']];
+    $data[] = ['test<em>blah</em>', ['#markup' => '<em>blah</em>'], ['test']];
+    $data[] = ['test <em>blah</em>', ['#markup' => '<em>blah</em>'], ['test', ' ']];
+    return $data;
+  }
+
+  /**
+   * @covers ::prefix
+   *
+   * @dataProvider providerRenderVariableSuffix
+   */
+  public function testRenderVariableSuffix($expected, $variable, array $prefixes) {
+    $args = $prefixes;
+    array_unshift($args, $variable);
+    $build = call_user_func_array([RenderVariable::class, 'suffix'], $args);
+    $render_output = $this->renderer->renderRoot($build);
+    $this->assertEquals($expected, (string) $render_output);
+  }
+
+  /**
+   * @return array
+   */
+  public function providerRenderVariableSuffix() {
+    $data = [];
+    $data[] = ['&lt;em&gt;blah&lt;/em&gt;test', '<em>blah</em>', ['test']];
+    $data[] = ['&lt;em&gt;blah&lt;/em&gt;1 2', '<em>blah</em>', ['1', ' ', '2']];
+    $data[] = ['<em>blah</em>test', ['#markup' => '<em>blah</em>'], ['test']];
+    $data[] = ['<em>blah</em> test', ['#markup' => '<em>blah</em>'], [' ', 'test']];
+    return $data;
+  }
+
+}