diff --git a/core/modules/system/tests/modules/form_test/config/schema/form_test.schema.yml b/core/modules/system/tests/modules/form_test/config/schema/form_test.schema.yml
new file mode 100644
index 0000000..3e38933
--- /dev/null
+++ b/core/modules/system/tests/modules/form_test/config/schema/form_test.schema.yml
@@ -0,0 +1,7 @@
+form_test.object:
+  type: mapping
+  label: 'Test form'
+  mapping:
+    bananas:
+      type: string
+      label: 'Bananas'
diff --git a/core/modules/system/src/Form/ThemeSettingsForm.php b/core/modules/system/src/Form/ThemeSettingsForm.php
index e855403..8e72246 100644
--- a/core/modules/system/src/Form/ThemeSettingsForm.php
+++ b/core/modules/system/src/Form/ThemeSettingsForm.php
@@ -182,7 +182,7 @@ public function buildForm(array $form, FormStateInterface $form_state, $theme =
       );
     }
 
-    if ((!$theme) || in_array('favicon', $features) && $this->moduleHandler->moduleExists('file')) {
+    if (((!$theme) || in_array('favicon', $features)) && $this->moduleHandler->moduleExists('file')) {
       $form['favicon'] = array(
         '#type' => 'details',
         '#title' => t('Shortcut icon settings'),