diff --git a/crates/ruff_python_ast/src/comparable.rs b/crates/ruff_python_ast/src/comparable.rs
index 4e08e98d1b..208b97d055 100644
--- a/crates/ruff_python_ast/src/comparable.rs
+++ b/crates/ruff_python_ast/src/comparable.rs
@@ -363,7 +363,7 @@ impl<'a> From<&'a ast::Number> for ComparableNumber<'a> {
     }
 }
 
-#[derive(Debug, PartialEq, Eq, Hash)]
+#[derive(Debug, Default, PartialEq, Eq, Hash)]
 pub struct ComparableArguments<'a> {
     args: Vec<ComparableExpr<'a>>,
     keywords: Vec<ComparableKeyword<'a>>,
@@ -1051,7 +1051,7 @@ pub struct StmtClassDef<'a> {
     decorator_list: Vec<ComparableDecorator<'a>>,
     name: &'a str,
     type_params: Option<ComparableTypeParams<'a>>,
-    arguments: Option<ComparableArguments<'a>>,
+    arguments: ComparableArguments<'a>,
     body: Vec<ComparableStmt<'a>>,
 }
 
@@ -1309,7 +1309,7 @@ impl<'a> From<&'a ast::Stmt> for ComparableStmt<'a> {
                 range: _,
             }) => Self::ClassDef(StmtClassDef {
                 name: name.as_str(),
-                arguments: arguments.as_ref().map(Into::into),
+                arguments: arguments.as_ref().map(Into::into).unwrap_or_default(),
                 body: body.iter().map(Into::into).collect(),
                 decorator_list: decorator_list.iter().map(Into::into).collect(),
                 type_params: type_params.as_ref().map(Into::into),
diff --git a/crates/ruff_python_formatter/tests/normalizer.rs b/crates/ruff_python_formatter/tests/normalizer.rs
index 5aab798d69..68c15349dd 100644
--- a/crates/ruff_python_formatter/tests/normalizer.rs
+++ b/crates/ruff_python_formatter/tests/normalizer.rs
@@ -32,33 +32,20 @@ impl Normalizer {
 
 impl Transformer for Normalizer {
     fn visit_stmt(&self, stmt: &mut Stmt) {
-        match stmt {
-            Stmt::ClassDef(class_def) => {
-                // Treat `class C: ...` and `class C(): ...` equivalently.
-                if class_def
-                    .arguments
-                    .as_ref()
-                    .is_some_and(|arguments| arguments.is_empty())
-                {
-                    class_def.arguments = None;
-                }
-            }
-            Stmt::Delete(delete) => {
-                // Treat `del a, b` and `del (a, b)` equivalently.
-                delete.targets = delete
-                    .targets
-                    .clone()
-                    .into_iter()
-                    .flat_map(|target| {
-                        if let Expr::Tuple(tuple) = target {
-                            Left(tuple.elts.into_iter())
-                        } else {
-                            Right(std::iter::once(target))
-                        }
-                    })
-                    .collect();
-            }
-            _ => {}
+        if let Stmt::Delete(delete) = stmt {
+            // Treat `del a, b` and `del (a, b)` equivalently.
+            delete.targets = delete
+                .targets
+                .clone()
+                .into_iter()
+                .flat_map(|target| {
+                    if let Expr::Tuple(tuple) = target {
+                        Left(tuple.elts.into_iter())
+                    } else {
+                        Right(std::iter::once(target))
+                    }
+                })
+                .collect();
         }
 
         transformer::walk_stmt(self, stmt);