Remove zcash_primitives as a zcash_note_encryption dev dependency.

This was only used to provide example code for Sapling usage of
the `NoteEncryption` struct; this example code has been moved
to `sapling::note_encryption`.

components/zcash_note_encryption/Cargo.toml

@@ -28,7 +28,6 @@ subtle = { version = "2.3", default-features = false }
 
 [dev-dependencies]
 ff = { version = "0.12", default-features = false }
-zcash_primitives = { version = "0.7", path = "../../zcash_primitives" }
 jubjub = "0.9"
 
 [features]

components/zcash_note_encryption/src/lib.rs

@@ -345,50 +345,6 @@ pub trait ShieldedOutput<D: Domain, const CIPHERTEXT_SIZE: usize> {
 ///
 /// Implements section 4.19 of the
 /// [Zcash Protocol Specification](https://zips.z.cash/protocol/nu5.pdf#saplingandorchardinband)
-/// NB: the example code is only covering the post-Canopy case.
-///
-/// # Examples
-///
-/// ```
-/// extern crate ff;
-/// extern crate rand_core;
-/// extern crate zcash_primitives;
-///
-/// use ff::Field;
-/// use rand_core::OsRng;
-/// use zcash_primitives::{
-///     keys::{OutgoingViewingKey, prf_expand},
-///     consensus::{TEST_NETWORK, TestNetwork, NetworkUpgrade, Parameters},
-///     memo::MemoBytes,
-///     sapling::{
-///         note_encryption::sapling_note_encryption,
-///         util::generate_random_rseed,
-///         Diversifier, PaymentAddress, Rseed, ValueCommitment
-///     },
-/// };
-///
-/// let mut rng = OsRng;
-///
-/// let diversifier = Diversifier([0; 11]);
-/// let pk_d = diversifier.g_d().unwrap();
-/// let to = PaymentAddress::from_parts(diversifier, pk_d).unwrap();
-/// let ovk = Some(OutgoingViewingKey([0; 32]));
-///
-/// let value = 1000;
-/// let rcv = jubjub::Fr::random(&mut rng);
-/// let cv = ValueCommitment {
-///     value,
-///     randomness: rcv.clone(),
-/// };
-/// let height = TEST_NETWORK.activation_height(NetworkUpgrade::Canopy).unwrap();
-/// let rseed = generate_random_rseed(&TEST_NETWORK, height, &mut rng);
-/// let note = to.create_note(value, rseed).unwrap();
-/// let cmu = note.cmu();
-///
-/// let mut enc = sapling_note_encryption::<_, TestNetwork>(ovk, note, to, MemoBytes::empty(), &mut rng);
-/// let encCiphertext = enc.encrypt_note_plaintext();
-/// let outCiphertext = enc.encrypt_outgoing_plaintext(&cv.commitment().into(), &cmu, &mut rng);
-/// ```
 pub struct NoteEncryption<D: Domain> {
     epk: D::EphemeralPublicKey,
     esk: D::EphemeralSecretKey,

zcash_primitives/src/sapling/note_encryption.rs

@@ -1,4 +1,7 @@
 //! Implementation of in-band secret distribution for Zcash transactions.
+//!
+//! NB: the example code is only covering the post-Canopy case.
+
 use blake2b_simd::{Hash as Blake2bHash, Params as Blake2bParams};
 use byteorder::{LittleEndian, WriteBytesExt};
 use ff::PrimeField;
@@ -381,6 +384,47 @@ impl<P: consensus::Parameters> BatchDomain for SaplingDomain<P> {
 ///
 /// Setting `ovk` to `None` represents the `ovk = ⊥` case, where the note cannot be
 /// recovered by the sender.
+///
+/// NB: the example code here only covers the post-Canopy case.
+///
+/// # Examples
+///
+/// ```
+/// use ff::Field;
+/// use rand_core::OsRng;
+/// use zcash_primitives::{
+///     keys::{OutgoingViewingKey, prf_expand},
+///     consensus::{TEST_NETWORK, TestNetwork, NetworkUpgrade, Parameters},
+///     memo::MemoBytes,
+///     sapling::{
+///         note_encryption::sapling_note_encryption,
+///         util::generate_random_rseed,
+///         Diversifier, PaymentAddress, Rseed, ValueCommitment
+///     },
+/// };
+///
+/// let mut rng = OsRng;
+///
+/// let diversifier = Diversifier([0; 11]);
+/// let pk_d = diversifier.g_d().unwrap();
+/// let to = PaymentAddress::from_parts(diversifier, pk_d).unwrap();
+/// let ovk = Some(OutgoingViewingKey([0; 32]));
+///
+/// let value = 1000;
+/// let rcv = jubjub::Fr::random(&mut rng);
+/// let cv = ValueCommitment {
+///     value,
+///     randomness: rcv.clone(),
+/// };
+/// let height = TEST_NETWORK.activation_height(NetworkUpgrade::Canopy).unwrap();
+/// let rseed = generate_random_rseed(&TEST_NETWORK, height, &mut rng);
+/// let note = to.create_note(value, rseed).unwrap();
+/// let cmu = note.cmu();
+///
+/// let mut enc = sapling_note_encryption::<_, TestNetwork>(ovk, note, to, MemoBytes::empty(), &mut rng);
+/// let encCiphertext = enc.encrypt_note_plaintext();
+/// let outCiphertext = enc.encrypt_outgoing_plaintext(&cv.commitment().into(), &cmu, &mut rng);
+/// ```
 pub fn sapling_note_encryption<R: RngCore, P: consensus::Parameters>(
     ovk: Option<OutgoingViewingKey>,
     note: Note,