Issue #3428696: TypeError: Unsupported operand types: array + null in LinkGenerator->generate()

src/Plugin/Field/FieldFormatter/LinkitFormatter.php

@@ -130,7 +130,7 @@ class LinkitFormatter extends LinkFormatter {
         if (!empty($parsed_url['fragment'])) {
           $url->setOption('fragment', $parsed_url['fragment']);
         }
-        $attributes = $url->getOption('attributes');
+        $attributes = (array) $url->getOption('attributes');
         // Restore rel and target options.
         if (!empty($settings['rel'])) {
           $attributes['rel'] = $settings['rel'];