diff --git a/core/lib/Drupal.php b/core/lib/Drupal.php
index da3e02a..eac2c40 100644
--- a/core/lib/Drupal.php
+++ b/core/lib/Drupal.php
@@ -546,10 +546,10 @@ public static function linkGenerator() {
    *   (optional) Defaults to FALSE. When TRUE, both the generated URL and its
    *   associated bubbleable metadata are returned.
    *
-   * @return string|\Drupal\Core\GeneratedLink
+   * @return \Drupal\Core\GeneratedLink
    *   An HTML string containing a link to the given route and parameters.
-   *   When $collect_bubbleable_metadata is TRUE, a GeneratedLink object is
-   *   returned, containing the generated link plus bubbleable metadata.
+   *   When $collect_bubbleable_metadata is TRUE, the GeneratedLink object has
+   *   bubbleable metadata.
    *
    * @see \Drupal\Core\Utility\LinkGeneratorInterface::generate()
    * @see \Drupal\Core\Url
diff --git a/core/lib/Drupal/Core/Menu/menu.api.php b/core/lib/Drupal/Core/Menu/menu.api.php
index 0ae528f..b6ad987 100644
--- a/core/lib/Drupal/Core/Menu/menu.api.php
+++ b/core/lib/Drupal/Core/Menu/menu.api.php
@@ -440,7 +440,11 @@ function hook_system_breadcrumb_alter(\Drupal\Core\Breadcrumb\Breadcrumb &$bread
  *   exposed as the 'link_generator' service or a link generated by _l(). If the
  *   link is a "route link", 'route_name' will be set, otherwise 'path' will be
  *   set. The following keys can be altered:
- *   - text: The link text for the anchor tag as a translated string.
+ *   - text: The link text for the anchor tag. If the hook implementation
+ *     changes this text is needs to preserve the safeness of the original text.
+ *     Using t() or \Drupal\Component\Utility\SafeMarkup::format() with
+ *     @placeholder is recommended as this will escape the original text if
+ *     necessary. If the resulting text is not marked safe it will be escaped.
  *   - url_is_active: Whether or not the link points to the currently active
  *     URL.
  *   - url: The \Drupal\Core\Url object.
@@ -468,7 +472,7 @@ function hook_system_breadcrumb_alter(\Drupal\Core\Breadcrumb\Breadcrumb &$bread
 function hook_link_alter(&$variables) {
   // Add a warning to the end of route links to the admin section.
   if (isset($variables['route_name']) && strpos($variables['route_name'], 'admin') !== FALSE) {
-    $variables['text'] .= ' (Warning!)';
+    $variables['text'] = t('@text (Warning!)', ['@text' => $variables['text']]);
   }
 }
 
diff --git a/core/lib/Drupal/Core/Utility/LinkGenerator.php b/core/lib/Drupal/Core/Utility/LinkGenerator.php
index 21f7617..c920e28 100644
--- a/core/lib/Drupal/Core/Utility/LinkGenerator.php
+++ b/core/lib/Drupal/Core/Utility/LinkGenerator.php
@@ -90,9 +90,7 @@ public function generate($text, Url $url, $collect_bubbleable_metadata = FALSE)
     if (is_array($text)) {
       $text = $this->renderer->render($text);
     }
-    elseif (!SafeMarkup::isSafe($text)) {
-      $text = Html::escape($text);
-    }
+
     // Start building a structured representation of our link to be altered later.
     $variables = array(
       'text' => $text,
@@ -170,12 +168,13 @@ public function generate($text, Url $url, $collect_bubbleable_metadata = FALSE)
     // attribute, and it is escaped by \Drupal\Core\Template\Attribute.
     $attributes['href'] = $url_string;
 
+    if (!SafeMarkup::isSafe($variables['text'])) {
+      $variables['text'] = Html::escape($variables['text']);
+    }
     $attributes = new Attribute($attributes);
     // This is safe because Attribute does escaping and $variables['text'] is
     // either rendered or escaped.
-    $result = SafeString::create('<a' . $attributes . '>' . $variables['text'] . '</a>');
-
-    return $generated_link->setGeneratedLink($result);
+    return $generated_link->setGeneratedLink('<a' . $attributes . '>' . $variables['text'] . '</a>');
   }
 
 }
diff --git a/core/lib/Drupal/Core/Utility/LinkGeneratorInterface.php b/core/lib/Drupal/Core/Utility/LinkGeneratorInterface.php
index 28b80f2..00d2566 100644
--- a/core/lib/Drupal/Core/Utility/LinkGeneratorInterface.php
+++ b/core/lib/Drupal/Core/Utility/LinkGeneratorInterface.php
@@ -66,8 +66,8 @@
    *
    * @return \Drupal\Core\GeneratedLink
    *   An HTML string containing a link to the given route and parameters.
-   *   When $collect_bubbleable_metadata is TRUE, a GeneratedLink object is
-   *   returned, containing the generated link plus bubbleable metadata.
+   *   When $collect_bubbleable_metadata is TRUE, the GeneratedLink object has
+   *   bubbleable metadata.
    *
    * @throws \Symfony\Component\Routing\Exception\RouteNotFoundException
    *   Thrown when the named route doesn't exist.
@@ -88,10 +88,10 @@ public function generate($text, Url $url, $collect_bubbleable_metadata = FALSE);
    *   (optional) Defaults to FALSE. When TRUE, both the generated link and its
    *   associated bubbleable metadata are returned.
    *
-   * @return string|\Drupal\Core\GeneratedLink
+   * @return \Drupal\Core\GeneratedLink
    *   An HTML string containing a link to the given route and parameters.
-   *   When $collect_bubbleable_metadata is TRUE, a GeneratedLink object is
-   *   returned, containing the generated link plus bubbleable metadata.
+   *   When $collect_bubbleable_metadata is TRUE, the GeneratedLink object has
+   *   bubbleable metadata.
    */
   public function generateFromLink(Link $link, $collect_bubbleable_metadata = FALSE);
 
diff --git a/core/modules/system/src/Tests/Utility/LinkGenerationTest.php b/core/modules/system/src/Tests/Utility/LinkGenerationTest.php
new file mode 100644
index 0000000..62c4d23
--- /dev/null
+++ b/core/modules/system/src/Tests/Utility/LinkGenerationTest.php
@@ -0,0 +1,70 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Utility\LinkGenerationTest.
+ */
+
+namespace Drupal\system\Tests\Utility;
+
+use Drupal\Component\Utility\SafeMarkup;
+use Drupal\Core\Render\RenderContext;
+use Drupal\Core\Url;
+use Drupal\simpletest\KernelTestBase;
+
+/**
+ * Tests link generation with hooks.
+ *
+ * @group Utility
+ */
+class LinkGenerationTest extends KernelTestBase {
+
+  public static $modules = ['link_generation_test'];
+
+  /**
+   * Tests how hook_link_alter() can affect escaping of the link text.
+   */
+  function testHookLinkAlter() {
+    $url = Url::fromUri('http://example.com');
+    $renderer = \Drupal::service('renderer');
+
+    $link = $renderer->executeInRenderContext(new RenderContext(), function () use ($url) {
+      return \Drupal::l(['#markup' => '<em>link with markup</em>'], $url);
+    });
+    $this->setRawContent($link);
+    $this->assertTrue(SafeMarkup::isSafe($link), 'The output of link generation is marked safe as it is a link.');
+    // Ensure the content of the link is not escaped.
+    $this->assertRaw('<em>link with markup</em>');
+
+    // Test just adding text to an already safe string.
+    \Drupal::state()->set('link_generation_test_link_alter', TRUE);
+    $link = $renderer->executeInRenderContext(new RenderContext(), function () use ($url) {
+      return \Drupal::l(['#markup' => '<em>link with markup</em>'], $url);
+    });
+    $this->setRawContent($link);
+    $this->assertTrue(SafeMarkup::isSafe($link), 'The output of link generation is marked safe as it is a link.');
+    // Ensure the content of the link is escaped.
+    $this->assertEscaped('<em>link with markup</em> <strong>Test!</strong>');
+
+    // Test passing a safe string to t().
+    \Drupal::state()->set('link_generation_test_link_alter_safe', TRUE);
+    $link = $renderer->executeInRenderContext(new RenderContext(), function () use ($url) {
+      return \Drupal::l(['#markup' => '<em>link with markup</em>'], $url);
+    });
+    $this->setRawContent($link);
+    $this->assertTrue(SafeMarkup::isSafe($link), 'The output of link generation is marked safe as it is a link.');
+    // Ensure the content of the link is escaped.
+    $this->assertRaw('<em>link with markup</em> <strong>Test!</strong>');
+
+    // Test passing an unsafe string to t().
+    $link = $renderer->executeInRenderContext(new RenderContext(), function () use ($url) {
+      return \Drupal::l('<em>link with markup</em>', $url);
+    });
+    $this->setRawContent($link);
+    $this->assertTrue(SafeMarkup::isSafe($link), 'The output of link generation is marked safe as it is a link.');
+    // Ensure the content of the link is escaped.
+    $this->assertEscaped('<em>link with markup</em>');
+    $this->assertRaw('<strong>Test!</strong>');
+  }
+
+}
diff --git a/core/modules/system/tests/modules/link_generation_test/link_generation_test.info.yml b/core/modules/system/tests/modules/link_generation_test/link_generation_test.info.yml
new file mode 100644
index 0000000..2f200a4
--- /dev/null
+++ b/core/modules/system/tests/modules/link_generation_test/link_generation_test.info.yml
@@ -0,0 +1,6 @@
+name: 'Link generation test support'
+type: module
+description: 'Test hooks fired in link generation.'
+package: Testing
+version: VERSION
+core: 8.x
diff --git a/core/modules/system/tests/modules/link_generation_test/link_generation_test.module b/core/modules/system/tests/modules/link_generation_test/link_generation_test.module
new file mode 100644
index 0000000..622a403
--- /dev/null
+++ b/core/modules/system/tests/modules/link_generation_test/link_generation_test.module
@@ -0,0 +1,21 @@
+<?php
+
+/**
+ * @file
+ * Helper module for the link generation tests.
+ */
+
+/**
+ * Implements hook_link_alter().
+ */
+function link_generation_test_link_alter(&$variables) {
+  if (\Drupal::state()->get('link_generation_test_link_alter', FALSE)) {
+    // Add a text to the end of links.
+    if (\Drupal::state()->get('link_generation_test_link_alter_safe', FALSE)) {
+      $variables['text'] = t('@text <strong>Test!</strong>', ['@text' => $variables['text']]);
+    }
+    else {
+      $variables['text'] .= ' <strong>Test!</strong>';
+    }
+  }
+}