diff -u b/core/includes/install.inc b/core/includes/install.inc
--- b/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -307,6 +307,10 @@
 }
 
 /**
+ * Helper for drupal_rewrite_settings().
+ *
+ * Checks whether this token represents a scalar.
+ *
  * @param int $type
  *   The token type
  *   @see token_name().
diff -u b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
--- b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Definition of Drupal\system\Tests\System\SettingsRewriteTest.
+ * Contains Drupal\system\Tests\System\SettingsRewriteTest.
  */
 
 namespace Drupal\system\Tests\System;
@@ -81,8 +81,8 @@
         'settings' => array(
           'has_index_value_scalar' => array(
             'foo' => array(
-              'baz' => array(
-                '.value' => FALSE,
+              'value' => array(
+                '.value' => array('value' => 2),
                 '.required' => TRUE,
                 '.comment' => 'comment',
               ),
@@ -91,7 +91,9 @@
         ),
         'expected' => <<<'EXPECTED'
 $has_index_value_scalar["foo"]["bar"] = "foo";
-$has_index_value_scalar['foo']['baz'] = false; // comment
+$has_index_value_scalar['foo']['value'] = array (
+  'value' => 2,
+); // comment
 EXPECTED
       ),
     );