zcash_client_backend: Remove unnecessary `ReceivedNote::traverse_opt`

zcash_client_backend/CHANGELOG.md

@@ -95,6 +95,8 @@ and this library adheres to Rust's notion of
 ### Removed
 - `zcash_client_backend::PoolType::is_receiver`: use
   `zcash_keys::Address::has_receiver` instead.
+- `zcash_client_backend::wallet::ReceivedNote::traverse_opt` removed as
+  unnecessary.
 
 ### Fixed
 - This release fixes an error in amount parsing in `zip321` that previously

zcash_client_backend/src/data_api/wallet/input_selection.rs

@@ -404,12 +404,10 @@ where
                     &shielded_inputs
                         .iter()
                         .cloned()
-                        .filter_map(|i| {
-                            i.traverse_opt(|wn| match wn {
-                                Note::Sapling(n) => Some(n),
+                        .filter_map(|i| match i.note() {
+                            Note::Sapling(n) => Some((*i.internal_note_id(), n.value())),
                             #[cfg(feature = "orchard")]
-                                _ => None,
-                            })
+                            Note::Orchard(_) => None,
                         })
                         .collect::<Vec<_>>()[..],
                     &sapling_outputs[..],
@@ -419,11 +417,9 @@ where
                     ::orchard::builder::BundleType::DEFAULT,
                     &shielded_inputs
                         .iter()
-                        .filter_map(|i| {
-                            i.clone().traverse_opt(|wn| match wn {
-                                Note::Orchard(n) => Some(n),
-                                _ => None,
-                            })
+                        .filter_map(|i| match i.note() {
+                            Note::Sapling(_) => None,
+                            Note::Orchard(n) => Some((*i.internal_note_id(), n.value())),
                         })
                         .collect::<Vec<_>>()[..],
                     &orchard_outputs[..],

zcash_client_backend/src/wallet.rs

@@ -430,26 +430,18 @@ impl<NoteRef, NoteT> ReceivedNote<NoteRef, NoteT> {
     pub fn note_commitment_tree_position(&self) -> Position {
         self.note_commitment_tree_position
     }
+}
 
-    /// Applies the given function to the `note` field of this ReceivedNote and returns
-    /// `None` if that function returns `None`, or otherwise a `Some` containing
-    /// a `ReceivedNote` with its `note` field swapped out for the result of the function.
-    ///
-    /// The name `traverse` refers to the general operation that has the Haskell type
-    /// `Applicative f => (a -> f b) -> t a -> f (t b)`, that this method specializes
-    /// with `ReceivedNote<NoteRef, _>` for `t` and `Option<_>` for `f`.
-    pub fn traverse_opt<B>(
-        self,
-        f: impl FnOnce(NoteT) -> Option<B>,
-    ) -> Option<ReceivedNote<NoteRef, B>> {
-        f(self.note).map(|n0| ReceivedNote {
-            note_id: self.note_id,
-            txid: self.txid,
-            output_index: self.output_index,
-            note: n0,
-            spending_key_scope: self.spending_key_scope,
-            note_commitment_tree_position: self.note_commitment_tree_position,
-        })
+impl<'a, NoteRef> sapling_fees::InputView<NoteRef> for (NoteRef, sapling::value::NoteValue) {
+    fn note_id(&self) -> &NoteRef {
+        &self.0
+    }
+
+    fn value(&self) -> NonNegativeAmount {
+        self.1
+            .inner()
+            .try_into()
+            .expect("Sapling note values are indirectly checked by consensus.")
     }
 }
 
@@ -467,6 +459,20 @@ impl<NoteRef> sapling_fees::InputView<NoteRef> for ReceivedNote<NoteRef, sapling
     }
 }
 
+#[cfg(feature = "orchard")]
+impl<'a, NoteRef> orchard_fees::InputView<NoteRef> for (NoteRef, orchard::value::NoteValue) {
+    fn note_id(&self) -> &NoteRef {
+        &self.0
+    }
+
+    fn value(&self) -> NonNegativeAmount {
+        self.1
+            .inner()
+            .try_into()
+            .expect("Orchard note values are indirectly checked by consensus.")
+    }
+}
+
 #[cfg(feature = "orchard")]
 impl<NoteRef> orchard_fees::InputView<NoteRef> for ReceivedNote<NoteRef, orchard::Note> {
     fn note_id(&self) -> &NoteRef {