diff --git a/src/TwigExtension/DefaultTwigExtension.php b/src/TwigExtension/DefaultTwigExtension.php
index b2fa111..f6e0436 100644
--- a/src/TwigExtension/DefaultTwigExtension.php
+++ b/src/TwigExtension/DefaultTwigExtension.php
@@ -167,7 +167,8 @@ class DefaultTwigExtension extends AbstractExtension {
    * {@inheritdoc}
    */
   public function getOperators() {
-    return [];
+    // Twig expects [unary_operators, binary_operators].
+    return [[], []];
   }

   /**