Move merkle_tree hash types

Currently we are defining the two merkle tree hash types in the `block`
module, a better home for them is the `merkle_tree` module.

This is an API breaking change because the types were public in the
`block` module, however the change should/could be unnoticeable to users
if they use the crate level re-export - which is maintained.

bitcoin/src/bip152.rs

@@ -374,10 +374,10 @@ mod test {
     use hex::FromHex;
 
     use super::*;
-    use crate::blockdata::block::TxMerkleNode;
     use crate::blockdata::locktime::absolute;
     use crate::blockdata::transaction;
     use crate::consensus::encode::{deserialize, serialize};
+    use crate::merkle_tree::TxMerkleNode;
     use crate::{Amount, CompactTarget, OutPoint, ScriptBuf, Sequence, TxIn, TxOut, Txid, Witness};
 
     fn dummy_tx(nonce: &[u8]) -> Transaction {

bitcoin/src/blockdata/block.rs

@@ -14,34 +14,21 @@ use io::{BufRead, Write};
 
 use super::Weight;
 use crate::blockdata::script;
-use crate::blockdata::transaction::{Transaction, Txid, Wtxid};
+use crate::blockdata::transaction::{Transaction, Wtxid};
 use crate::consensus::{encode, Decodable, Encodable, Params};
 use crate::internal_macros::{impl_consensus_encoding, impl_hashencode};
+use crate::merkle_tree::{self, TxMerkleNode, WitnessMerkleNode};
 use crate::pow::{CompactTarget, Target, Work};
 use crate::prelude::*;
-use crate::{merkle_tree, VarInt};
+use crate::VarInt;
 
 hashes::hash_newtype! {
     /// A bitcoin block hash.
     pub struct BlockHash(sha256d::Hash);
-    /// A hash of the Merkle tree branch or root for transactions.
-    pub struct TxMerkleNode(sha256d::Hash);
-    /// A hash corresponding to the Merkle tree root for witness data.
-    pub struct WitnessMerkleNode(sha256d::Hash);
     /// A hash corresponding to the witness structure commitment in the coinbase transaction.
     pub struct WitnessCommitment(sha256d::Hash);
 }
 impl_hashencode!(BlockHash);
-impl_hashencode!(TxMerkleNode);
-impl_hashencode!(WitnessMerkleNode);
-
-impl From<Txid> for TxMerkleNode {
-    fn from(txid: Txid) -> Self { Self::from_byte_array(txid.to_byte_array()) }
-}
-
-impl From<Wtxid> for WitnessMerkleNode {
-    fn from(wtxid: Wtxid) -> Self { Self::from_byte_array(wtxid.to_byte_array()) }
-}
 
 /// Bitcoin block header.
 ///

bitcoin/src/consensus/encode.rs

@@ -23,9 +23,10 @@ use io::{BufRead, Cursor, Read, Write};
 
 use crate::bip152::{PrefilledTransaction, ShortId};
 use crate::bip158::{FilterHash, FilterHeader};
-use crate::blockdata::block::{self, BlockHash, TxMerkleNode};
+use crate::blockdata::block::{self, BlockHash};
 use crate::blockdata::transaction::{Transaction, TxIn, TxOut};
 use crate::consensus::{DecodeError, IterReader};
+use crate::merkle_tree::TxMerkleNode;
 #[cfg(feature = "std")]
 use crate::p2p::{
     address::{AddrV2Message, Address},

bitcoin/src/lib.rs

@@ -116,7 +116,7 @@ pub use crate::{
     amount::{Amount, Denomination, SignedAmount},
     bip158::{FilterHash, FilterHeader},
     bip32::XKeyIdentifier,
-    blockdata::block::{self, Block, BlockHash, TxMerkleNode, WitnessMerkleNode, WitnessCommitment},
+    blockdata::block::{self, Block, BlockHash, WitnessCommitment},
     blockdata::constants,
     blockdata::fee_rate::FeeRate,
     blockdata::locktime::{self, absolute, relative},
@@ -132,7 +132,7 @@ pub use crate::{
     crypto::ecdsa,
     crypto::key::{self, PrivateKey, PubkeyHash, PublicKey, CompressedPublicKey, WPubkeyHash, XOnlyPublicKey},
     crypto::sighash::{self, LegacySighash, SegwitV0Sighash, TapSighash, TapSighashTag},
-    merkle_tree::MerkleBlock,
+    merkle_tree::{MerkleBlock, TxMerkleNode, WitnessMerkleNode},
     network::{Network, NetworkKind},
     pow::{CompactTarget, Target, Work},
     psbt::Psbt,

bitcoin/src/merkle_tree/block.rs

@@ -14,10 +14,11 @@ use core::fmt;
 use io::{BufRead, Write};
 
 use self::MerkleBlockError::*;
-use crate::blockdata::block::{self, Block, TxMerkleNode};
+use crate::blockdata::block::{self, Block};
 use crate::blockdata::transaction::{Transaction, Txid};
 use crate::blockdata::weight::Weight;
 use crate::consensus::encode::{self, Decodable, Encodable, MAX_VEC_SIZE};
+use crate::merkle_tree::TxMerkleNode;
 use crate::prelude::*;
 
 /// Data structure that represents a block header paired to a partial merkle tree.

bitcoin/src/merkle_tree/mod.rs

@@ -18,16 +18,35 @@ mod block;
 use core::cmp::min;
 use core::iter;
 
-use hashes::Hash;
+use hashes::{sha256d, Hash};
 use io::Write;
 
 use crate::consensus::encode::Encodable;
+use crate::internal_macros::impl_hashencode;
 use crate::prelude::*;
+use crate::{Txid, Wtxid};
 
 #[rustfmt::skip]
 #[doc(inline)]
 pub use self::block::{MerkleBlock, MerkleBlockError, PartialMerkleTree};
 
+hashes::hash_newtype! {
+    /// A hash of the Merkle tree branch or root for transactions.
+    pub struct TxMerkleNode(sha256d::Hash);
+    /// A hash corresponding to the Merkle tree root for witness data.
+    pub struct WitnessMerkleNode(sha256d::Hash);
+}
+impl_hashencode!(TxMerkleNode);
+impl_hashencode!(WitnessMerkleNode);
+
+impl From<Txid> for TxMerkleNode {
+    fn from(txid: Txid) -> Self { Self::from_byte_array(txid.to_byte_array()) }
+}
+
+impl From<Wtxid> for WitnessMerkleNode {
+    fn from(wtxid: Wtxid) -> Self { Self::from_byte_array(wtxid.to_byte_array()) }
+}
+
 /// Calculates the merkle root of a list of *hashes*, inline (in place) in `hashes`.
 ///
 /// In most cases, you'll want to use [`calculate_root`] instead. Please note, calling this function