diff --git a/src/subclass.rs b/src/subclass.rs
index 6c6ee31..bf905d9 100644
--- a/src/subclass.rs
+++ b/src/subclass.rs
@@ -31,7 +31,7 @@
 ///   #[subclass(superclass("MyCppSuperclass"))]
 ///   struct Bar {};
 ///   ```
-/// * as a directive within the [include_cpp] macro, in which case you
+/// * as a directive within the [crate::include_cpp] macro, in which case you
 ///   must provide two arguments of the superclass and then the
 ///   subclass:
 ///   ```
@@ -102,18 +102,14 @@
 /// A type showing how the Rust side of a Rust/C++ subclass pair refers to
 /// the C++ side.
 #[doc(hidden)]
+#[derive(Default)]
 pub enum CppSubclassCppPeerHolder<CppPeer: CppSubclassCppPeer> {
+    #[default]
     Empty,
     Owned(Box<UniquePtr<CppPeer>>),
     Unowned(*mut CppPeer),
 }
 
-impl<CppPeer: CppSubclassCppPeer> Default for CppSubclassCppPeerHolder<CppPeer> {
-    fn default() -> Self {
-        CppSubclassCppPeerHolder::Empty
-    }
-}
-
 impl<CppPeer: CppSubclassCppPeer> CppSubclassCppPeerHolder<CppPeer> {
     fn pin_mut(&mut self) -> Pin<&mut CppPeer> {
         match self {