sinsemilla::merkle: Remove MERKLE_DEPTH constant.

src/circuit.rs

@@ -392,7 +392,7 @@ impl plonk::Circuit<pallas::Base> for Circuit {
 
         // Merkle path validity check.
         let anchor = {
-            let path = self.path.map(|typed_path| {
+            let path: Option<[pallas::Base; MERKLE_DEPTH_ORCHARD]> = self.path.map(|typed_path| {
                 // TODO: Replace with array::map once MSRV is 1.55.0.
                 gen_const_array(|i| typed_path[i].inner())
             });

src/circuit/gadget/sinsemilla/merkle.rs

@@ -16,9 +16,6 @@ pub(in crate::circuit) mod chip;
 /// SWU hash-to-curve personalization for the Merkle CRH generator
 pub const MERKLE_CRH_PERSONALIZATION: &str = "z.cash:Orchard-MerkleCRH";
 
-/// Depth of Merkle tree
-pub(crate) const MERKLE_DEPTH: usize = 32;
-
 /// Instructions to check the validity of a Merkle path of a given `PATH_LENGTH`.
 /// The hash function used is a Sinsemilla instance with `K`-bit words.
 /// The hash function can process `MAX_WORDS` words.
@@ -136,7 +133,7 @@ where
 pub mod tests {
     use super::{
         chip::{MerkleChip, MerkleConfig},
-        MerklePath, MERKLE_DEPTH,
+        MerklePath,
     };
 
     use crate::{
@@ -160,6 +157,8 @@ pub mod tests {
     use rand::{rngs::OsRng, RngCore};
     use std::convert::TryInto;
 
+    const MERKLE_DEPTH: usize = 32;
+
     #[derive(Default)]
     struct MyCircuit {
         leaf: Option<pallas::Base>,

src/circuit/gadget/sinsemilla/merkle/chip.rs

@@ -5,7 +5,7 @@ use halo2::{
 };
 use pasta_curves::{arithmetic::FieldExt, pallas};
 
-use super::{MerkleInstructions, MERKLE_DEPTH};
+use super::MerkleInstructions;
 
 use crate::{
     circuit::gadget::{
@@ -180,7 +180,7 @@ where
     }
 }
 
-impl<Hash, Commit, F>
+impl<Hash, Commit, F, const MERKLE_DEPTH: usize>
     MerkleInstructions<pallas::Affine, MERKLE_DEPTH, { sinsemilla::K }, { sinsemilla::C }>
     for MerkleChip<Hash, Commit, F>
 where