From eb731a6e2fee31ab2c32db02390bda35f3bcb08f Mon Sep 17 00:00:00 2001
From: Deirdre Connolly <deirdre@zfnd.org>
Date: Tue, 28 Jul 2020 02:27:02 -0400
Subject: [PATCH] Add note commitment tree Position type

---
 zebra-chain/src/treestate/note_commitment_tree.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/zebra-chain/src/treestate/note_commitment_tree.rs b/zebra-chain/src/treestate/note_commitment_tree.rs
index 5a43d7946..b2698df07 100644
--- a/zebra-chain/src/treestate/note_commitment_tree.rs
+++ b/zebra-chain/src/treestate/note_commitment_tree.rs
@@ -18,6 +18,12 @@ use proptest_derive::Arbitrary;
 
 use crate::serialization::{SerializationError, ZcashDeserialize, ZcashSerialize};
 
+/// The index of a note’s commitment at the leafmost layer of its Note
+/// Commitment Tree.
+///
+/// https://zips.z.cash/protocol/protocol.pdf#merkletree
+pub struct Position(pub(crate) u64);
+
 // XXX: Depending on if we implement SproutNoteCommitmentTree or
 // similar, it may be worth it to define a NoteCommitmentTree trait.