have view set methods return references

node/network/statement-distribution/src/lib.rs

@@ -720,12 +720,12 @@ async fn update_peer_view_and_send_unlocked(
 
 	// Remove entries for all relay-parents in the old view but not the new.
 	for removed in old_view.difference(&peer_data.view) {
-		let _ = peer_data.view_knowledge.remove(&removed);
+		let _ = peer_data.view_knowledge.remove(removed);
 	}
 
 	// Add entries for all relay-parents in the new view but not the old.
 	// Furthermore, send all statements we have for those relay parents.
-	let new_view = peer_data.view.difference(&old_view).collect::<Vec<_>>();
+	let new_view = peer_data.view.difference(&old_view).copied().collect::<Vec<_>>();
 	for new in new_view.iter().copied() {
 		peer_data.view_knowledge.insert(new, Default::default());
 

node/primitives/src/lib.rs

@@ -95,13 +95,13 @@ pub struct View(pub Vec<Hash>);
 
 impl View {
 	/// Returns an iterator of the hashes present in `Self` but not in `other`.
-	pub fn difference<'a>(&'a self, other: &'a View) -> impl Iterator<Item = Hash> + 'a {
-		self.0.iter().cloned().filter(move |h| !other.contains(h))
+	pub fn difference<'a>(&'a self, other: &'a View) -> impl Iterator<Item = &'a Hash> + 'a {
+		self.0.iter().filter(move |h| !other.contains(h))
 	}
 
 	/// An iterator containing hashes present in both `Self` and in `other`.
-	pub fn intersection<'a>(&'a self, other: &'a View) -> impl Iterator<Item = Hash> + 'a {
-		self.0.iter().cloned().filter(move |h| other.contains(h))
+	pub fn intersection<'a>(&'a self, other: &'a View) -> impl Iterator<Item = &'a Hash> + 'a {
+		self.0.iter().filter(move |h| other.contains(h))
 	}
 
 	/// Whether the view contains a given hash.