diff --git a/src/options.rs b/src/options.rs
index cf615a2..ff57b5f 100644
--- a/src/options.rs
+++ b/src/options.rs
@@ -716,7 +716,7 @@ mod tests {
         // SerializableBranch appears as a field value in real config files.
         #[derive(Debug, serde::Deserialize)]
         struct Helper {
-            #[serde(flatten)]
+            #[expect(dead_code)]
             branch: SerializableBranch,
         }