Fix clippy warnings (#1385)

## Issue Addressed

NA

## Proposed Changes

Fixes most clippy warnings and ignores the rest of them, see issue #1388.

consensus/types/src/beacon_state.rs

@@ -1073,7 +1073,7 @@ impl<T: EthSpec> BeaconState<T> {
             genesis_time: self.genesis_time,
             genesis_validators_root: self.genesis_validators_root,
             slot: self.slot,
-            fork: self.fork.clone(),
+            fork: self.fork,
             latest_block_header: self.latest_block_header.clone(),
             block_roots: self.block_roots.clone(),
             state_roots: self.state_roots.clone(),
@@ -1088,9 +1088,9 @@ impl<T: EthSpec> BeaconState<T> {
             previous_epoch_attestations: self.previous_epoch_attestations.clone(),
             current_epoch_attestations: self.current_epoch_attestations.clone(),
             justification_bits: self.justification_bits.clone(),
-            previous_justified_checkpoint: self.previous_justified_checkpoint.clone(),
-            current_justified_checkpoint: self.current_justified_checkpoint.clone(),
-            finalized_checkpoint: self.finalized_checkpoint.clone(),
+            previous_justified_checkpoint: self.previous_justified_checkpoint,
+            current_justified_checkpoint: self.current_justified_checkpoint,
+            finalized_checkpoint: self.finalized_checkpoint,
             committee_caches: if config.committee_caches {
                 self.committee_caches.clone()
             } else {

consensus/types/src/beacon_state/tree_hash_cache.rs

@@ -5,6 +5,7 @@ use crate::{BeaconState, EthSpec, Hash256, Unsigned, Validator};
 use cached_tree_hash::{int_log, CacheArena, CachedTreeHash, TreeHashCache};
 use rayon::prelude::*;
 use ssz_derive::{Decode, Encode};
+use std::cmp::Ordering;
 use tree_hash::{mix_in_length, MerkleHasher, TreeHash};
 
 /// The number of fields on a beacon state.
@@ -270,8 +271,8 @@ impl ParallelValidatorTreeHash {
     /// This function makes assumptions that the `validators` list will only change in accordance
     /// with valid per-block/per-slot state transitions.
     fn leaves(&mut self, validators: &[Validator]) -> Result<Vec<Vec<Hash256>>, Error> {
-        if self.len() < validators.len() {
-            validators.iter().skip(self.len()).for_each(|v| {
+        match self.len().cmp(&validators.len()) {
+            Ordering::Less => validators.iter().skip(self.len()).for_each(|v| {
                 if self
                     .arenas
                     .last()
@@ -287,9 +288,11 @@ impl ParallelValidatorTreeHash {
                         .expect("Cannot reach this block if arenas is empty.");
                     caches.push(v.new_tree_hash_cache(arena))
                 }
-            })
-        } else if validators.len() < self.len() {
-            return Err(Error::ValidatorRegistryShrunk);
+            }),
+            Ordering::Greater => {
+                return Err(Error::ValidatorRegistryShrunk);
+            }
+            Ordering::Equal => (),
         }
 
         self.arenas

consensus/types/src/test_utils/builders/testing_attestation_data_builder.rs

@@ -24,9 +24,9 @@ impl TestingAttestationDataBuilder {
         let is_previous_epoch = slot.epoch(T::slots_per_epoch()) != current_epoch;
 
         let mut source = if is_previous_epoch {
-            state.previous_justified_checkpoint.clone()
+            state.previous_justified_checkpoint
         } else {
-            state.current_justified_checkpoint.clone()
+            state.current_justified_checkpoint
         };
 
         let mut target = if is_previous_epoch {

consensus/types/src/test_utils/builders/testing_attester_slashing_builder.rs

@@ -42,7 +42,7 @@ impl TestingAttesterSlashingBuilder {
             slot,
             index,
             beacon_block_root: hash_1,
-            source: checkpoint_1.clone(),
+            source: checkpoint_1,
             target: checkpoint_1,
         };