resolved merge conflicts due to Treehash macro implementation (lighthouse-246)

eth2/types/src/attestation.rs

@@ -2,11 +2,11 @@ use super::{AggregatePublicKey, AggregateSignature, AttestationData, Bitfield, H
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz::TreeHash;
-use ssz_derive::{Decode, Encode};
+use ssz_derive::{Decode, Encode, TreeHash};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct Attestation {
     pub aggregation_bitfield: Bitfield,
     pub data: AttestationData,
@@ -37,22 +37,11 @@ impl Attestation {
     }
 }
 
-impl TreeHash for Attestation {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.aggregation_bitfield.hash_tree_root_internal());
-        result.append(&mut self.data.hash_tree_root_internal());
-        result.append(&mut self.custody_bitfield.hash_tree_root_internal());
-        result.append(&mut self.aggregate_signature.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/attestation_data.rs

@@ -2,8 +2,8 @@ use crate::test_utils::TestRandom;
 use crate::{AttestationDataAndCustodyBit, Crosslink, Epoch, Hash256, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz::TreeHash;
-use ssz_derive::{Decode, Encode};
+use ssz_derive::{Decode, Encode, TreeHash};
 use test_random_derive::TestRandom;
 
 pub const SSZ_ATTESTION_DATA_LENGTH: usize = {
@@ -17,7 +17,9 @@ pub const SSZ_ATTESTION_DATA_LENGTH: usize = {
     32 // justified_block_root
 };
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize, Hash, Encode, Decode, TestRandom)]
+#[derive(
+    Debug, Clone, PartialEq, Default, Serialize, Hash, Encode, Decode, TreeHash, TestRandom,
+)]
 pub struct AttestationData {
     pub slot: Slot,
     pub shard: u64,
@@ -45,26 +47,11 @@ impl AttestationData {
     }
 }
 
-impl TreeHash for AttestationData {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slot.hash_tree_root_internal());
-        result.append(&mut self.shard.hash_tree_root_internal());
-        result.append(&mut self.beacon_block_root.hash_tree_root_internal());
-        result.append(&mut self.epoch_boundary_root.hash_tree_root_internal());
-        result.append(&mut self.shard_block_root.hash_tree_root_internal());
-        result.append(&mut self.latest_crosslink.hash_tree_root_internal());
-        result.append(&mut self.justified_epoch.hash_tree_root_internal());
-        result.append(&mut self.justified_block_root.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/attestation_data_and_custody_bit.rs

@@ -2,25 +2,14 @@ use super::AttestationData;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::TreeHash;
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize, Encode, Decode)]
+#[derive(Debug, Clone, PartialEq, Default, Serialize, Encode, Decode, TreeHash)]
 pub struct AttestationDataAndCustodyBit {
     pub data: AttestationData,
     pub custody_bit: bool,
 }
 
-impl TreeHash for AttestationDataAndCustodyBit {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.data.hash_tree_root_internal());
-        // TODO: add bool ssz
-        // result.append(custody_bit.hash_tree_root_internal());
-        ssz::hash(&result)
-    }
-}
-
 impl<T: RngCore> TestRandom<T> for AttestationDataAndCustodyBit {
     fn random_for_test(rng: &mut T) -> Self {
         Self {
@@ -35,7 +24,7 @@ impl<T: RngCore> TestRandom<T> for AttestationDataAndCustodyBit {
 mod test {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/attester_slashing.rs

@@ -1,30 +1,20 @@
 use crate::{test_utils::TestRandom, SlashableAttestation};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct AttesterSlashing {
     pub slashable_attestation_1: SlashableAttestation,
     pub slashable_attestation_2: SlashableAttestation,
 }
 
-impl TreeHash for AttesterSlashing {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slashable_attestation_1.hash_tree_root_internal());
-        result.append(&mut self.slashable_attestation_2.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/beacon_block.rs

@@ -3,11 +3,11 @@ use crate::{BeaconBlockBody, ChainSpec, Eth1Data, Hash256, ProposalSignedData, S
 use bls::Signature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz::TreeHash;
-use ssz_derive::{Decode, Encode};
+use ssz_derive::{Decode, Encode, TreeHash};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct BeaconBlock {
     pub slot: Slot,
     pub parent_root: Hash256,
@@ -61,25 +61,11 @@ impl BeaconBlock {
     }
 }
 
-impl TreeHash for BeaconBlock {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slot.hash_tree_root_internal());
-        result.append(&mut self.parent_root.hash_tree_root_internal());
-        result.append(&mut self.state_root.hash_tree_root_internal());
-        result.append(&mut self.randao_reveal.hash_tree_root_internal());
-        result.append(&mut self.eth1_data.hash_tree_root_internal());
-        result.append(&mut self.signature.hash_tree_root_internal());
-        result.append(&mut self.body.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/beacon_block_body.rs

@@ -2,11 +2,10 @@ use super::{Attestation, AttesterSlashing, Deposit, Exit, ProposerSlashing};
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct BeaconBlockBody {
     pub proposer_slashings: Vec<ProposerSlashing>,
     pub attester_slashings: Vec<AttesterSlashing>,
@@ -15,23 +14,11 @@ pub struct BeaconBlockBody {
     pub exits: Vec<Exit>,
 }
 
-impl TreeHash for BeaconBlockBody {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.proposer_slashings.hash_tree_root_internal());
-        result.append(&mut self.attester_slashings.hash_tree_root_internal());
-        result.append(&mut self.attestations.hash_tree_root_internal());
-        result.append(&mut self.deposits.hash_tree_root_internal());
-        result.append(&mut self.exits.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/casper_slashing.rs

@@ -2,30 +2,20 @@ use super::SlashableVoteData;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct CasperSlashing {
     pub slashable_vote_data_1: SlashableVoteData,
     pub slashable_vote_data_2: SlashableVoteData,
 }
 
-impl TreeHash for CasperSlashing {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slashable_vote_data_1.hash_tree_root_internal());
-        result.append(&mut self.slashable_vote_data_2.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/crosslink.rs

@@ -2,11 +2,12 @@ use crate::test_utils::TestRandom;
 use crate::{Epoch, Hash256};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize, Hash, Encode, Decode, TestRandom)]
+#[derive(
+    Debug, Clone, PartialEq, Default, Serialize, Hash, Encode, Decode, TreeHash, TestRandom,
+)]
 pub struct Crosslink {
     pub epoch: Epoch,
     pub shard_block_root: Hash256,
@@ -22,20 +23,11 @@ impl Crosslink {
     }
 }
 
-impl TreeHash for Crosslink {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.epoch.hash_tree_root_internal());
-        result.append(&mut self.shard_block_root.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/deposit.rs

@@ -2,32 +2,21 @@ use super::{DepositData, Hash256};
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct Deposit {
     pub branch: Vec<Hash256>,
     pub index: u64,
     pub deposit_data: DepositData,
 }
 
-impl TreeHash for Deposit {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.branch.hash_tree_root_internal());
-        result.append(&mut self.index.hash_tree_root_internal());
-        result.append(&mut self.deposit_data.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/deposit_data.rs

@@ -2,32 +2,21 @@ use super::DepositInput;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct DepositData {
     pub amount: u64,
     pub timestamp: u64,
     pub deposit_input: DepositInput,
 }
 
-impl TreeHash for DepositData {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.amount.hash_tree_root_internal());
-        result.append(&mut self.timestamp.hash_tree_root_internal());
-        result.append(&mut self.deposit_input.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/deposit_input.rs

@@ -3,32 +3,21 @@ use crate::test_utils::TestRandom;
 use bls::{PublicKey, Signature};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct DepositInput {
     pub pubkey: PublicKey,
     pub withdrawal_credentials: Hash256,
     pub proof_of_possession: Signature,
 }
 
-impl TreeHash for DepositInput {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.pubkey.hash_tree_root_internal());
-        result.append(&mut self.withdrawal_credentials.hash_tree_root_internal());
-        result.append(&mut self.proof_of_possession.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/eth1_data.rs

@@ -2,31 +2,21 @@ use super::Hash256;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
 // Note: this is refer to as DepositRootVote in specs
-#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct Eth1Data {
     pub deposit_root: Hash256,
     pub block_hash: Hash256,
 }
 
-impl TreeHash for Eth1Data {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.deposit_root.hash_tree_root_internal());
-        result.append(&mut self.block_hash.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/eth1_data_vote.rs

@@ -2,31 +2,21 @@ use super::Eth1Data;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
 // Note: this is refer to as DepositRootVote in specs
-#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct Eth1DataVote {
     pub eth1_data: Eth1Data,
     pub vote_count: u64,
 }
 
-impl TreeHash for Eth1DataVote {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.eth1_data.hash_tree_root_internal());
-        result.append(&mut self.vote_count.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/exit.rs

@@ -2,32 +2,21 @@ use crate::{test_utils::TestRandom, Epoch};
 use bls::Signature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct Exit {
     pub epoch: Epoch,
     pub validator_index: u64,
     pub signature: Signature,
 }
 
-impl TreeHash for Exit {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.epoch.hash_tree_root_internal());
-        result.append(&mut self.validator_index.hash_tree_root_internal());
-        result.append(&mut self.signature.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/fork.rs

@@ -1,11 +1,10 @@
 use crate::{test_utils::TestRandom, Epoch};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, Clone, PartialEq, Default, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct Fork {
     pub previous_version: u64,
     pub current_version: u64,
@@ -28,21 +27,11 @@ impl Fork {
     }
 }
 
-impl TreeHash for Fork {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.previous_version.hash_tree_root_internal());
-        result.append(&mut self.current_version.hash_tree_root_internal());
-        result.append(&mut self.epoch.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/pending_attestation.rs

@@ -2,11 +2,10 @@ use crate::test_utils::TestRandom;
 use crate::{AttestationData, Bitfield, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct PendingAttestation {
     pub aggregation_bitfield: Bitfield,
     pub data: AttestationData,
@@ -14,22 +13,11 @@ pub struct PendingAttestation {
     pub inclusion_slot: Slot,
 }
 
-impl TreeHash for PendingAttestation {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.aggregation_bitfield.hash_tree_root_internal());
-        result.append(&mut self.data.hash_tree_root_internal());
-        result.append(&mut self.custody_bitfield.hash_tree_root_internal());
-        result.append(&mut self.inclusion_slot.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/proposal_signed_data.rs

@@ -2,32 +2,21 @@ use crate::test_utils::TestRandom;
 use crate::{Hash256, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct ProposalSignedData {
     pub slot: Slot,
     pub shard: u64,
     pub block_root: Hash256,
 }
 
-impl TreeHash for ProposalSignedData {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slot.hash_tree_root_internal());
-        result.append(&mut self.shard.hash_tree_root_internal());
-        result.append(&mut self.block_root.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/proposer_slashing.rs

@@ -3,11 +3,10 @@ use crate::test_utils::TestRandom;
 use bls::Signature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct ProposerSlashing {
     pub proposer_index: u64,
     pub proposal_data_1: ProposalSignedData,
@@ -16,23 +15,11 @@ pub struct ProposerSlashing {
     pub proposal_signature_2: Signature,
 }
 
-impl TreeHash for ProposerSlashing {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.proposer_index.hash_tree_root_internal());
-        result.append(&mut self.proposal_data_1.hash_tree_root_internal());
-        result.append(&mut self.proposal_signature_1.hash_tree_root_internal());
-        result.append(&mut self.proposal_data_2.hash_tree_root_internal());
-        result.append(&mut self.proposal_signature_2.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/shard_reassignment_record.rs

@@ -1,32 +1,21 @@
 use crate::{test_utils::TestRandom, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct ShardReassignmentRecord {
     pub validator_index: u64,
     pub shard: u64,
     pub slot: Slot,
 }
 
-impl TreeHash for ShardReassignmentRecord {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.validator_index.hash_tree_root_internal());
-        result.append(&mut self.shard.hash_tree_root_internal());
-        result.append(&mut self.slot.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/slashable_attestation.rs

@@ -1,11 +1,10 @@
 use crate::{test_utils::TestRandom, AggregateSignature, AttestationData, Bitfield};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct SlashableAttestation {
     pub validator_indices: Vec<u64>,
     pub data: AttestationData,
@@ -13,22 +12,11 @@ pub struct SlashableAttestation {
     pub aggregate_signature: AggregateSignature,
 }
 
-impl TreeHash for SlashableAttestation {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.validator_indices.hash_tree_root_internal());
-        result.append(&mut self.data.hash_tree_root_internal());
-        result.append(&mut self.custody_bitfield.hash_tree_root_internal());
-        result.append(&mut self.aggregate_signature.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/types/src/slashable_vote_data.rs

@@ -4,11 +4,10 @@ use crate::test_utils::TestRandom;
 use bls::AggregateSignature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
-#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct SlashableVoteData {
     pub custody_bit_0_indices: Vec<u32>,
     pub custody_bit_1_indices: Vec<u32>,
@@ -37,24 +36,13 @@ impl SlashableVoteData {
     }
 }
 
-impl TreeHash for SlashableVoteData {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.custody_bit_0_indices.hash_tree_root_internal());
-        result.append(&mut self.custody_bit_1_indices.hash_tree_root_internal());
-        result.append(&mut self.data.hash_tree_root_internal());
-        result.append(&mut self.aggregate_signature.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::chain_spec::ChainSpec;
     use crate::slot_epoch::{Epoch, Slot};
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_is_double_vote_true() {

eth2/types/src/validator_registry_delta_block.rs

@@ -2,12 +2,11 @@ use crate::{test_utils::TestRandom, Hash256, Slot};
 use bls::PublicKey;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode, TreeHash};
-use ssz_derive::{Decode, Encode};
 use test_random_derive::TestRandom;
 
 // The information gathered from the PoW chain validator registration function.
-#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode, TestRandom)]
+#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode, TreeHash, TestRandom)]
 pub struct ValidatorRegistryDeltaBlock {
     pub latest_registry_delta_root: Hash256,
     pub validator_index: u32,
@@ -29,23 +28,11 @@ impl Default for ValidatorRegistryDeltaBlock {
     }
 }
 
-impl TreeHash for ValidatorRegistryDeltaBlock {
-    fn hash_tree_root_internal(&self) -> Vec<u8> {
-        let mut result: Vec<u8> = vec![];
-        result.append(&mut self.latest_registry_delta_root.hash_tree_root_internal());
-        result.append(&mut self.validator_index.hash_tree_root_internal());
-        result.append(&mut self.pubkey.hash_tree_root_internal());
-        result.append(&mut self.slot.hash_tree_root_internal());
-        result.append(&mut self.flag.hash_tree_root_internal());
-        hash(&result)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::{ssz_encode, Decodable};
+    use ssz::{ssz_encode, Decodable, TreeHash};
 
     #[test]
     pub fn test_ssz_round_trip() {

eth2/utils/ssz/src/impl_tree_hash.rs

@@ -32,6 +32,12 @@ impl TreeHash for usize {
     }
 }
 
+impl TreeHash for bool {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
+        ssz_encode(self)
+    }
+}
+
 impl TreeHash for Address {
     fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)

eth2/utils/ssz/src/tree_hash.rs

@@ -7,9 +7,7 @@ pub trait TreeHash {
     fn hash_tree_root_internal(&self) -> Vec<u8>;
     fn hash_tree_root(&self) -> Vec<u8> {
         let mut result = self.hash_tree_root_internal();
-        if result.len() < HASHSIZE {
         zpad(&mut result, HASHSIZE);
-        }
         result
     }
 }

eth2/utils/ssz_derive/src/lib.rs

@@ -2,6 +2,7 @@
 //!
 //! - `#[derive(Encode)]`
 //! - `#[derive(Decode)]`
+//! - `#[derive(TreeHash)]`
 //!
 //! These macros provide SSZ encoding/decoding for a `struct`. Fields are encoded/decoded in the
 //! order they are defined.
@@ -126,3 +127,34 @@ pub fn ssz_decode_derive(input: TokenStream) -> TokenStream {
     };
     output.into()
 }
+
+/// Implements `ssz::TreeHash` for some `struct`.
+///
+/// Fields are processed in the order they are defined.
+#[proc_macro_derive(TreeHash)]
+pub fn ssz_tree_hash_derive(input: TokenStream) -> TokenStream {
+    let item = parse_macro_input!(input as DeriveInput);
+
+    let name = &item.ident;
+
+    let struct_data = match &item.data {
+        syn::Data::Struct(s) => s,
+        _ => panic!("ssz_derive only supports structs."),
+    };
+
+    let field_idents = get_named_field_idents(&struct_data);
+
+    let output = quote! {
+        impl ssz::TreeHash for #name {
+            fn hash_tree_root_internal(&self) -> Vec<u8> {
+                let mut result: Vec<u8> = vec![];
+                #(
+                    result.append(&mut self.#field_idents.hash_tree_root_internal());
+                )*
+
+                ssz::hash(&result)
+            }
+        }
+    };
+    output.into()
+}