diff --git a/core/lib/Drupal/Core/Extension/Discovery/RecursiveExtensionFilterIterator.php b/core/lib/Drupal/Core/Extension/Discovery/RecursiveExtensionFilterIterator.php
index 73cf386..79a2726 100644
--- a/core/lib/Drupal/Core/Extension/Discovery/RecursiveExtensionFilterIterator.php
+++ b/core/lib/Drupal/Core/Extension/Discovery/RecursiveExtensionFilterIterator.php
@@ -97,7 +97,7 @@ class RecursiveExtensionFilterIterator extends \RecursiveFilterIterator {
    */
   public function __construct(\RecursiveIterator $iterator, array $blacklist = []) {
     parent::__construct($iterator);
-    $this->blacklist += $blacklist;
+    $this->blacklist = array_merge($this->blacklist, $blacklist);
   }
 
   /**
@@ -121,6 +121,8 @@ public function acceptTests($flag = FALSE) {
    */
   public function getChildren() {
     $filter = parent::getChildren();
+    // Pass on the blacklist.
+    $filter->blacklist = $this->blacklist;
     // Pass the $acceptTests flag forward to child iterators.
     $filter->acceptTests($this->acceptTests);
     return $filter;
diff --git a/core/modules/system/src/Tests/Common/SystemListingTest.php b/core/modules/system/src/Tests/Common/SystemListingTest.php
index a9d1549..ec3fcda 100644
--- a/core/modules/system/src/Tests/Common/SystemListingTest.php
+++ b/core/modules/system/src/Tests/Common/SystemListingTest.php
@@ -55,4 +55,27 @@ function testDirectoryPrecedence() {
       )));
     }
   }
+
+  /**
+   * Tests that directories matching file_scan_ignore_directories are ignored
+   */
+  function testFileScanIgnoreDirectory() {
+    $listing = new ExtensionDiscovery(\Drupal::root(), FALSE);
+    $listing->setProfileDirectories(array('core/profiles/testing'));
+    $files = $listing->scan('module');
+    $this->assertTrue(isset($files['drupal_system_listing_compatible_test']));
+
+    // Reset the static to force a rescan of the directories.
+    $reflected_class = new \ReflectionClass(ExtensionDiscovery::class);
+    $reflected_property = $reflected_class->getProperty('files');
+    $reflected_property->setAccessible(true);
+    $reflected_property->setValue($reflected_class, []);
+
+    $this->settingsSet('file_scan_ignore_directories', ['drupal_system_listing_compatible_test']);
+    $listing = new ExtensionDiscovery(\Drupal::root(), FALSE);
+    $listing->setProfileDirectories(array('core/profiles/testing'));
+    $files = $listing->scan('module');
+    $this->assertFalse(isset($files['drupal_system_listing_compatible_test']));
+  }
+
 }