diff --git a/serde_derive/src/ser.rs b/serde_derive/src/ser.rs
index 28dbbbc7..b9a9dce2 100644
--- a/serde_derive/src/ser.rs
+++ b/serde_derive/src/ser.rs
@@ -483,7 +483,9 @@ fn serialize_variant(
             (attr::TagType::Adjacent { tag, content }, false) => {
                 serialize_adjacently_tagged_variant(params, variant, cattrs, tag, content)
             }
-            (attr::TagType::None, _) | (_, true) => serialize_untagged_variant(params, variant, cattrs),
+            (attr::TagType::None, _) | (_, true) => {
+                serialize_untagged_variant(params, variant, cattrs)
+            }
         });
 
         quote! {
diff --git a/test_suite/tests/test_annotations.rs b/test_suite/tests/test_annotations.rs
index 9dd89456..d59f4031 100644
--- a/test_suite/tests/test_annotations.rs
+++ b/test_suite/tests/test_annotations.rs
@@ -2481,7 +2481,10 @@ fn test_partially_untagged_enum_generic() {
     }
 
     #[derive(Serialize, Deserialize, PartialEq, Debug)]
-    enum E<A, B, C> where A: Trait<C, Assoc2=B> {
+    enum E<A, B, C>
+    where
+        A: Trait<C, Assoc2 = B>,
+    {
         A(A::Assoc),
         #[serde(untagged)]
         B(A::Assoc2),