Fix clippy warnings (#1385)

## Issue Addressed

NA

## Proposed Changes

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

consensus/state_processing/src/per_block_processing.rs

@@ -301,7 +301,7 @@ pub fn process_proposer_slashings<T: EthSpec>(
     // We have to verify in series because an invalid block may contain multiple slashings
     // for the same validator, and we need to correctly detect and reject that.
     proposer_slashings
-        .into_iter()
+        .iter()
         .enumerate()
         .try_for_each(|(i, proposer_slashing)| {
             verify_proposer_slashing(proposer_slashing, &state, verify_signatures, spec)
@@ -508,7 +508,7 @@ pub fn process_exits<T: EthSpec>(
 ) -> Result<(), BlockProcessingError> {
     // Verify and apply each exit in series. We iterate in series because higher-index exits may
     // become invalid due to the application of lower-index ones.
-    for (i, exit) in voluntary_exits.into_iter().enumerate() {
+    for (i, exit) in voluntary_exits.iter().enumerate() {
         verify_exit(&state, exit, verify_signatures, spec).map_err(|e| e.into_with_index(i))?;
 
         initiate_validator_exit(state, exit.message.validator_index as usize, spec)?;

consensus/state_processing/src/per_block_processing/block_processing_builder.rs

@@ -129,7 +129,7 @@ impl<'a, T: EthSpec> BlockProcessingBuilder<'a, T> {
             signature: AggregateSignature::new(),
         };
 
-        for (i, &validator_index) in committee.committee.into_iter().enumerate() {
+        for (i, &validator_index) in committee.committee.iter().enumerate() {
             if should_sign(i, validator_index) {
                 attestation
                     .sign(

consensus/state_processing/src/per_block_processing/block_signature_verifier.rs

@@ -83,7 +83,7 @@ where
     /// add signatures, and the `verify`
     pub fn new(state: &'a BeaconState<T>, get_pubkey: F, spec: &'a ChainSpec) -> Self {
         Self {
-            get_pubkey: get_pubkey,
+            get_pubkey,
             state,
             spec,
             sets: vec![],
@@ -129,7 +129,7 @@ where
             .sets
             .into_par_iter()
             .chunks(num_chunks)
-            .map(|chunk| verify_signature_sets(chunk))
+            .map(verify_signature_sets)
             .reduce(|| true, |current, this| current && this);
 
         if result {

consensus/state_processing/src/per_block_processing/signature_sets.rs

@@ -314,8 +314,8 @@ pub fn deposit_pubkey_signature_message(
 
 /// Returns the signature set for some set of deposit signatures, made with
 /// `deposit_pubkey_signature_message`.
-pub fn deposit_signature_set<'a>(
-    pubkey_signature_message: &'a (PublicKey, Signature, Vec<u8>),
+pub fn deposit_signature_set(
+    pubkey_signature_message: &(PublicKey, Signature, Vec<u8>),
 ) -> SignatureSet {
     let (pubkey, signature, message) = pubkey_signature_message;
 

consensus/state_processing/src/per_block_processing/verify_attestation.rs

@@ -93,8 +93,8 @@ fn verify_casper_ffg_vote<T: EthSpec>(
         verify!(
             data.source == state.current_justified_checkpoint,
             Invalid::WrongJustifiedCheckpoint {
-                state: state.current_justified_checkpoint.clone(),
-                attestation: data.source.clone(),
+                state: state.current_justified_checkpoint,
+                attestation: data.source,
                 is_current: true,
             }
         );
@@ -103,8 +103,8 @@ fn verify_casper_ffg_vote<T: EthSpec>(
         verify!(
             data.source == state.previous_justified_checkpoint,
             Invalid::WrongJustifiedCheckpoint {
-                state: state.previous_justified_checkpoint.clone(),
-                attestation: data.source.clone(),
+                state: state.previous_justified_checkpoint,
+                attestation: data.source,
                 is_current: false,
             }
         );

consensus/state_processing/src/per_epoch_processing.rs

@@ -91,11 +91,11 @@ pub fn process_justification_and_finalization<T: EthSpec>(
     let previous_epoch = state.previous_epoch();
     let current_epoch = state.current_epoch();
 
-    let old_previous_justified_checkpoint = state.previous_justified_checkpoint.clone();
-    let old_current_justified_checkpoint = state.current_justified_checkpoint.clone();
+    let old_previous_justified_checkpoint = state.previous_justified_checkpoint;
+    let old_current_justified_checkpoint = state.current_justified_checkpoint;
 
     // Process justifications
-    state.previous_justified_checkpoint = state.current_justified_checkpoint.clone();
+    state.previous_justified_checkpoint = state.current_justified_checkpoint;
     state.justification_bits.shift_up(1)?;
 
     if total_balances

consensus/state_processing/src/per_slot_processing.rs

@@ -21,11 +21,12 @@ pub fn per_slot_processing<T: EthSpec>(
 ) -> Result<Option<EpochProcessingSummary>, Error> {
     cache_state(state, state_root)?;
 
-    let mut summary = None;
-
-    if state.slot > spec.genesis_slot && (state.slot + 1) % T::slots_per_epoch() == 0 {
-        summary = Some(per_epoch_processing(state, spec)?);
-    }
+    let summary = if state.slot > spec.genesis_slot && (state.slot + 1) % T::slots_per_epoch() == 0
+    {
+        Some(per_epoch_processing(state, spec)?)
+    } else {
+        None
+    };
 
     state.slot += 1;