diff -u b/core/includes/theme.inc b/core/includes/theme.inc
--- b/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -650,6 +650,7 @@
         'url' => NULL,
       );
 
+      $li_attributes = array();
       $keys = ['title', 'url'];
       $link_element = array(
         '#type' => 'link',
@@ -675,7 +676,6 @@
         'url' => NULL,
       );
 
-      $li_attributes = array();
       $keys = ['title', 'url'];
       $link_element = array(
         '#type' => 'link',
only in patch2:
unchanged:
--- a/core/modules/system/src/Tests/Theme/FunctionsTest.php
+++ b/core/modules/system/src/Tests/Theme/FunctionsTest.php
@@ -274,11 +274,11 @@ function testLinks() {
     $expected_links .= '<li class="a-link"><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li class="plain-text"><span class="a/class">' . Html::escape('Plain "text"') . '</span></li>';
     $expected_links .= '<li class="html-text"><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';
-    $expected_links .= '<li data-drupal-link-system-path="&lt;front&gt;" class="front-page"><a href="' . Url::fromRoute('<front>')->toString() . '" data-drupal-link-system-path="&lt;front&gt;">' . Html::escape('Front page') . '</a></li>';
-    $expected_links .= '<li data-drupal-link-system-path="router_test/test1" class="router-test"><a href="' . \Drupal::urlGenerator()->generate('router_test.1') . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Test route') . '</a></li>';
+    $expected_links .= '<li class="front-page"><a href="' . Url::fromRoute('<front>')->toString() . '" data-drupal-link-system-path="&lt;front&gt;">' . Html::escape('Front page') . '</a></li>';
+    $expected_links .= '<li class="router-test"><a href="' . \Drupal::urlGenerator()->generate('router_test.1') . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Test route') . '</a></li>';
     $query = array('key' => 'value');
     $encoded_query = Html::escape(Json::encode($query));
-    $expected_links .= '<li data-drupal-link-query="' . $encoded_query . '" data-drupal-link-system-path="router_test/test1" class="query-test"><a href="' . \Drupal::urlGenerator()->generate('router_test.1', $query) . '" data-drupal-link-query="' . $encoded_query . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Query test route') . '</a></li>';
+    $expected_links .= '<li class="query-test"><a href="' . \Drupal::urlGenerator()->generate('router_test.1', $query) . '" data-drupal-link-query="' . $encoded_query . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Query test route') . '</a></li>';
     $expected_links .= '</ul>';
     $expected = $expected_heading . $expected_links;
     $this->assertThemeOutput('links', $variables, $expected);
@@ -395,11 +395,11 @@ function testIndexedKeyedLinks() {
     $expected_links .= '<li><a href="' . Url::fromUri('base:a/link')->toString() . '">' . Html::escape('A <link>') . '</a></li>';
     $expected_links .= '<li><span class="a/class">' . Html::escape('Plain "text"') . '</span></li>';
     $expected_links .= '<li><span class="unescaped">' . Html::escape('potentially unsafe text that <should> be escaped') . '</span></li>';
-    $expected_links .= '<li data-drupal-link-system-path="&lt;front&gt;"><a href="' . Url::fromRoute('<front>')->toString() . '" data-drupal-link-system-path="&lt;front&gt;">' . Html::escape('Front page') . '</a></li>';
-    $expected_links .= '<li data-drupal-link-system-path="router_test/test1"><a href="' . \Drupal::urlGenerator()->generate('router_test.1') . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Test route') . '</a></li>';
+    $expected_links .= '<li><a href="' . Url::fromRoute('<front>')->toString() . '" data-drupal-link-system-path="&lt;front&gt;">' . Html::escape('Front page') . '</a></li>';
+    $expected_links .= '<li><a href="' . \Drupal::urlGenerator()->generate('router_test.1') . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Test route') . '</a></li>';
     $query = ['key' => 'value'];
     $encoded_query = Html::escape(Json::encode($query));
-    $expected_links .= '<li data-drupal-link-query="' . $encoded_query . '" data-drupal-link-system-path="router_test/test1"><a href="' . \Drupal::urlGenerator()->generate('router_test.1', $query) . '" data-drupal-link-query="' . $encoded_query . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Query test route') . '</a></li>';
+    $expected_links .= '<li><a href="' . \Drupal::urlGenerator()->generate('router_test.1', $query) . '" data-drupal-link-query="' . $encoded_query . '" data-drupal-link-system-path="router_test/test1">' . Html::escape('Query test route') . '</a></li>';
     $expected_links .= '</ul>';
     $expected = $expected_heading . $expected_links;
     $this->assertThemeOutput('links', $variables, $expected);