David Galeano
--- a/core/lib/Drupal/Core/Render/Element.php
+++ b/core/lib/Drupal/Core/Render/Element.php
        // Only trigger an error if the value is not null.
        // @see https://www.drupal.org/node/1283892
        elseif (isset($value)) {
-          trigger_error(new FormattableMarkup('"@key" is an invalid render array key', ['@key' => $key]), E_USER_ERROR);
+          trigger_error(new FormattableMarkup(
+            'Expected an array but got a @type',