From a560101bb2f2c9635aaa8a77256fef0c49a113eb Mon Sep 17 00:00:00 2001
From: Kris Nuttycombe <kris@electriccoin.co>
Date: Thu, 8 Apr 2021 10:08:00 -0600
Subject: [PATCH] Remove spurious mut references.

---
 components/zcash_note_encryption/src/lib.rs     | 2 +-
 zcash_primitives/benches/note_decryption.rs     | 4 ++--
 zcash_primitives/src/sapling/note_encryption.rs | 6 +++---
 zcash_primitives/src/transaction/builder.rs     | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/components/zcash_note_encryption/src/lib.rs b/components/zcash_note_encryption/src/lib.rs
index 520168098..c4e2d87a7 100644
--- a/components/zcash_note_encryption/src/lib.rs
+++ b/components/zcash_note_encryption/src/lib.rs
@@ -268,7 +268,7 @@ impl<D: Domain> NoteEncryption<D> {
 
     /// Generates `outCiphertext` for this note.
     pub fn encrypt_outgoing_plaintext<R: RngCore>(
-        &mut self,
+        &self,
         cv: &D::ValueCommitment,
         cm: &D::NoteCommitment,
         rng: &mut R,
diff --git a/zcash_primitives/benches/note_decryption.rs b/zcash_primitives/benches/note_decryption.rs
index f08ef58d9..f9e142ed7 100644
--- a/zcash_primitives/benches/note_decryption.rs
+++ b/zcash_primitives/benches/note_decryption.rs
@@ -5,7 +5,7 @@ use zcash_primitives::{
     consensus::{NetworkUpgrade::Canopy, Parameters, TestNetwork, TEST_NETWORK},
     memo::MemoBytes,
     sapling::{
-        note_encryption::{sapling_note_encryption, try_sapling_note_decryption, Memo},
+        note_encryption::{sapling_note_encryption, try_sapling_note_decryption},
         util::generate_random_rseed,
         Diversifier, PaymentAddress, SaplingIvk, ValueCommitment,
     },
@@ -38,7 +38,7 @@ fn bench_note_decryption(c: &mut Criterion) {
         let note = pa.create_note(value, rseed).unwrap();
         let cmu = note.cmu();
 
-        let mut ne =
+        let ne =
             sapling_note_encryption::<_, TestNetwork>(None, note, pa, MemoBytes::empty(), &mut rng);
         let ephemeral_key = *ne.epk();
         let enc_ciphertext = ne.encrypt_note_plaintext();
diff --git a/zcash_primitives/src/sapling/note_encryption.rs b/zcash_primitives/src/sapling/note_encryption.rs
index daad0e2cd..dd1e2e4dc 100644
--- a/zcash_primitives/src/sapling/note_encryption.rs
+++ b/zcash_primitives/src/sapling/note_encryption.rs
@@ -554,7 +554,7 @@ mod tests {
         let cmu = note.cmu();
 
         let ovk = OutgoingViewingKey([0; 32]);
-        let mut ne = sapling_note_encryption::<_, TestNetwork>(
+        let ne = sapling_note_encryption::<_, TestNetwork>(
             Some(ovk),
             note,
             pa,
@@ -1591,7 +1591,7 @@ mod tests {
             // Test encryption
             //
 
-            let mut ne = NoteEncryption::<SaplingDomain<TestNetwork>>::new_with_esk(
+            let ne = NoteEncryption::<SaplingDomain<TestNetwork>>::new_with_esk(
                 esk,
                 Some(ovk),
                 note,
@@ -1599,7 +1599,7 @@ mod tests {
                 MemoBytes::from_bytes(&tv.memo).unwrap(),
             );
 
-            assert_eq!(&ne.encrypt_note_plaintext().as_ref()[..], &tv.c_enc[..]);
+            assert_eq!(ne.encrypt_note_plaintext().as_ref(), &tv.c_enc[..]);
             assert_eq!(
                 &ne.encrypt_outgoing_plaintext(&cv, &cmu, &mut OsRng)[..],
                 &tv.c_out[..]
diff --git a/zcash_primitives/src/transaction/builder.rs b/zcash_primitives/src/transaction/builder.rs
index ca3cc2a64..8cdc954d0 100644
--- a/zcash_primitives/src/transaction/builder.rs
+++ b/zcash_primitives/src/transaction/builder.rs
@@ -162,7 +162,7 @@ impl<P: consensus::Parameters> SaplingOutput<P> {
         ctx: &mut Pr::SaplingProvingContext,
         rng: &mut R,
     ) -> OutputDescription {
-        let mut encryptor = sapling_note_encryption::<R, P>(
+        let encryptor = sapling_note_encryption::<R, P>(
             self.ovk,
             self.note.clone(),
             self.to.clone(),