diff -u b/core/lib/Drupal/Core/Config/ExtensionInstallStorage.php b/core/lib/Drupal/Core/Config/ExtensionInstallStorage.php --- b/core/lib/Drupal/Core/Config/ExtensionInstallStorage.php +++ b/core/lib/Drupal/Core/Config/ExtensionInstallStorage.php @@ -26,7 +26,7 @@ protected function getAllFolders() { if (!isset($this->folders)) { $this->folders = $this->getComponentNames('module', array_keys(\Drupal::moduleHandler()->getModuleList())); - $this->folders += $this->getComponentNames('theme', array_keys(array_filter(list_themes(TRUE), function ($theme) {return $theme->status;}))); + $this->folders += $this->getComponentNames('theme', array_keys(array_filter(list_themes(), function ($theme) {return $theme->status;}))); } return $this->folders; }