Fix various clippy lints

eth2/types/src/attestation.rs

@@ -1,6 +1,5 @@
 use super::{AggregatePublicKey, AggregateSignature, AttestationData, Bitfield, Hash256};
 use crate::test_utils::TestRandom;
-use bls::bls_verify_aggregate;
 use rand::RngCore;
 use serde_derive::Serialize;
 use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};

eth2/types/src/beacon_state.rs

@@ -283,7 +283,7 @@ impl BeaconState {
 
         shuffled_active_validator_indices
             .honey_badger_split(committees_per_epoch as usize)
-            .filter_map(|slice: &[usize]| Some(slice.to_vec()))
+            .map(|slice: &[usize]| slice.to_vec())
             .collect()
     }
 
@@ -522,11 +522,9 @@ impl BeaconState {
             .filter(|i| eligible(*i))
             .collect();
         eligable_indices.sort_by_key(|i| self.validator_registry[*i].exit_epoch);
-        let mut withdrawn_so_far = 0;
-        for index in eligable_indices {
-            self.prepare_validator_for_withdrawal(index);
-            withdrawn_so_far += 1;
-            if withdrawn_so_far >= spec.max_withdrawals_per_epoch {
+        for (withdrawn_so_far, index) in eligable_indices.iter().enumerate() {
+            self.prepare_validator_for_withdrawal(*index);
+            if withdrawn_so_far as u64 >= spec.max_withdrawals_per_epoch {
                 break;
             }
         }
@@ -796,11 +794,7 @@ impl BeaconState {
         for (i, a) in attestations.iter().enumerate() {
             let participants =
                 self.get_attestation_participants(&a.data, &a.aggregation_bitfield, spec)?;
-            if participants
-                .iter()
-                .find(|i| **i == validator_index)
-                .is_some()
-            {
+            if participants.iter().any(|i| *i == validator_index) {
                 included_attestations.push(i);
             }
         }

eth2/types/src/slot_epoch.rs

@@ -13,9 +13,10 @@ use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
 use slog;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, ssz_encode, Decodable, DecodeError, Encodable, SszStream, TreeHash};
 use std::cmp::{Ord, Ordering};
 use std::fmt;
+use std::hash::{Hash, Hasher};
 use std::iter::Iterator;
 use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Rem, Sub, SubAssign};
 
@@ -243,6 +244,18 @@ macro_rules! impl_ssz {
     };
 }
 
+macro_rules! impl_hash {
+    ($type: ident) => {
+        // Implemented to stop clippy lint:
+        // https://rust-lang.github.io/rust-clippy/master/index.html#derive_hash_xor_eq
+        impl Hash for $type {
+            fn hash<H: Hasher>(&self, state: &mut H) {
+                ssz_encode(self).hash(state)
+            }
+        }
+    };
+}
+
 macro_rules! impl_common {
     ($type: ident) => {
         impl_from_into_u64!($type);
@@ -252,13 +265,14 @@ macro_rules! impl_common {
         impl_math!($type);
         impl_display!($type);
         impl_ssz!($type);
+        impl_hash!($type);
     };
 }
 
-#[derive(Eq, Debug, Clone, Copy, Default, Serialize, Hash)]
+#[derive(Eq, Debug, Clone, Copy, Default, Serialize)]
 pub struct Slot(u64);
 
-#[derive(Eq, Debug, Clone, Copy, Default, Serialize, Hash)]
+#[derive(Eq, Debug, Clone, Copy, Default, Serialize)]
 pub struct Epoch(u64);
 
 impl_common!(Slot);
@@ -269,7 +283,7 @@ impl Slot {
         Slot(slot)
     }
 
-    pub fn epoch(&self, epoch_length: u64) -> Epoch {
+    pub fn epoch(self, epoch_length: u64) -> Epoch {
         Epoch::from(self.0 / epoch_length)
     }
 
@@ -287,11 +301,11 @@ impl Epoch {
         Epoch(u64::max_value())
     }
 
-    pub fn start_slot(&self, epoch_length: u64) -> Slot {
+    pub fn start_slot(self, epoch_length: u64) -> Slot {
         Slot::from(self.0.saturating_mul(epoch_length))
     }
 
-    pub fn end_slot(&self, epoch_length: u64) -> Slot {
+    pub fn end_slot(self, epoch_length: u64) -> Slot {
         Slot::from(
             self.0
                 .saturating_add(1)

eth2/types/src/validator.rs

@@ -78,7 +78,7 @@ impl Default for Validator {
 impl<T: RngCore> TestRandom<T> for StatusFlags {
     fn random_for_test(rng: &mut T) -> Self {
         let options = vec![StatusFlags::InitiatedExit, StatusFlags::Withdrawable];
-        options[(rng.next_u32() as usize) % options.len()].clone()
+        options[(rng.next_u32() as usize) % options.len()]
     }
 }
 
@@ -130,7 +130,7 @@ impl TreeHash for Validator {
         result.append(&mut self.exit_epoch.hash_tree_root());
         result.append(&mut self.withdrawal_epoch.hash_tree_root());
         result.append(&mut self.penalized_epoch.hash_tree_root());
-        result.append(&mut (status_flag_to_byte(self.status_flags) as u64).hash_tree_root());
+        result.append(&mut u64::from(status_flag_to_byte(self.status_flags)).hash_tree_root());
         hash(&result)
     }
 }