Add various fixes to clippy lints

Thou shalt appease clippy

eth2/types/src/beacon_state.rs

@@ -422,7 +422,7 @@ impl<T: EthSpec> BeaconState<T> {
             };
             let effective_balance = self.validator_registry[candidate_index].effective_balance;
             if (effective_balance * MAX_RANDOM_BYTE)
-                >= (spec.max_effective_balance * random_byte as u64)
+                >= (spec.max_effective_balance * u64::from(random_byte))
             {
                 break candidate_index;
             }

eth2/types/src/beacon_state/committee_cache.rs

@@ -162,7 +162,6 @@ impl CommitteeCache {
         let i = self.shuffled_position(validator_index)?;
 
         (0..self.committee_count)
-            .into_iter()
             .map(|nth_committee| (nth_committee, self.compute_committee_range(nth_committee)))
             .find(|(_, range)| {
                 if let Some(range) = range {

eth2/types/src/chain_spec.rs

@@ -174,7 +174,7 @@ impl ChainSpec {
             /*
              * Time parameters
              */
-            genesis_time: u32::max_value() as u64,
+            genesis_time: u64::from(u32::max_value()),
             seconds_per_slot: 6,
             min_attestation_inclusion_delay: 4,
             min_seed_lookahead: Epoch::new(1),

eth2/types/src/slot_epoch.rs

@@ -77,7 +77,7 @@ impl Epoch {
     /// Position of some slot inside an epoch, if any.
     ///
     /// E.g., the first `slot` in `epoch` is at position `0`.
-    pub fn position(&self, slot: Slot, slots_per_epoch: u64) -> Option<usize> {
+    pub fn position(self, slot: Slot, slots_per_epoch: u64) -> Option<usize> {
         let start = self.start_slot(slots_per_epoch);
         let end = self.end_slot(slots_per_epoch);
 

eth2/types/src/test_utils/builders/testing_beacon_block_builder.rs

@@ -271,7 +271,7 @@ fn build_proposer_slashing<T: EthSpec>(
         Signature::new(message, domain, secret_key)
     };
 
-    TestingProposerSlashingBuilder::double_vote::<T, _>(validator_index, signer, spec)
+    TestingProposerSlashingBuilder::double_vote::<T, _>(validator_index, signer)
 }
 
 /// Builds an `AttesterSlashing` for some `validator_indices`.

eth2/types/src/test_utils/builders/testing_proposer_slashing_builder.rs

@@ -17,7 +17,7 @@ impl TestingProposerSlashingBuilder {
     /// - `domain: Domain`
     ///
     /// Where domain is a domain "constant" (e.g., `spec.domain_attestation`).
-    pub fn double_vote<T, F>(proposer_index: u64, signer: F, spec: &ChainSpec) -> ProposerSlashing
+    pub fn double_vote<T, F>(proposer_index: u64, signer: F) -> ProposerSlashing
     where
         T: EthSpec,
         F: Fn(u64, &[u8], Epoch, Domain) -> Signature,

eth2/types/src/test_utils/serde_utils.rs

@@ -13,6 +13,7 @@ where
     u8::from_str_radix(&s.as_str()[2..], 16).map_err(D::Error::custom)
 }
 
+#[allow(clippy::trivially_copy_pass_by_ref)] // Serde requires the `byte` to be a ref.
 pub fn u8_to_hex_str<S>(byte: &u8, serializer: S) -> Result<S::Ok, S::Error>
 where
     S: Serializer,