3 files changed, 7 insertions, 9 deletions
diff --git a/src/data/graph.rs b/src/data/graph.rs
index ea27e03..de958c3 100644
--- a/src/data/graph.rs
+++ b/src/data/graph.rs
@@ -749,20 +749,12 @@ impl<N, E> IndexMut<EdgeIndex> for Graph<N, E> {
 /// The walker does not borrow from the graph, so it lets you step through
 /// neighbors or incident edges while also mutating graph weights, as
 /// in the following example:
+#[derive(Clone)]
 pub struct WalkNeighbors {
     skip_start: NodeIndex,
     next: [EdgeIndex; 2],
 }
 
-impl Clone for WalkNeighbors {
-    fn clone(&self) -> Self {
-        WalkNeighbors {
-            skip_start: self.skip_start,
-            next: self.next,
-        }
-    }
-}
-
 /// Reference to a `Graph` edge.
 #[derive(Debug)]
 pub struct EdgeReference<'a, E: 'a> {
diff --git a/src/data/maybe_serializable_data.rs b/src/data/maybe_serializable_data.rs
index db38963..8b14e1a 100644
--- a/src/data/maybe_serializable_data.rs
+++ b/src/data/maybe_serializable_data.rs
@@ -9,6 +9,9 @@ pub trait MaybeSerializableData: DowncastSync {
     fn as_serialize(&self) -> Option<(u32, &dyn Serialize)> {
         None
     }
+
+    /// Clones `self`.
+    fn clone_dyn(&self) -> Box<dyn MaybeSerializableData>;
 }
 
 impl_downcast!(sync MaybeSerializableData);
diff --git a/src/data/pubsub.rs b/src/data/pubsub.rs
index b2c9e27..80fb3a2 100644
--- a/src/data/pubsub.rs
+++ b/src/data/pubsub.rs
@@ -5,6 +5,7 @@ use std::marker::PhantomData;
 
 /// A permanent subscription to a pub-sub queue.
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
+#[derive(Clone)]
 pub struct Subscription<T> {
     // Position on the cursor array.
     id: u32,
@@ -12,6 +13,7 @@ pub struct Subscription<T> {
 }
 
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
+#[derive(Clone)]
 struct PubSubCursor {
     // Position on the offset array.
     id: u32,
@@ -36,6 +38,7 @@ impl PubSubCursor {
 
 /// A pub-sub queue.
 #[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
+#[derive(Clone)]
 pub struct PubSub<T> {
     deleted_messages: u32,
     deleted_offsets: u32,