Clippy 1.49.0 updates and dht persistence test fix (#2156)

## Issue Addressed

`test_dht_persistence` failing

## Proposed Changes

Bind `NetworkService::start` to an underscore prefixed variable rather than `_`.  `_` was causing it to be dropped immediately

This was failing 5/100 times before this update, but I haven't been able to get it to fail after updating it

Co-authored-by: realbigsean <seananderson33@gmail.com>

consensus/cached_tree_hash/src/impls.rs

@@ -24,15 +24,15 @@ pub fn u64_leaf_count(len: usize) -> usize {
     (len + vals_per_chunk - 1) / vals_per_chunk
 }
 
-pub fn hash256_iter<'a>(
-    values: &'a [Hash256],
-) -> impl Iterator<Item = [u8; BYTES_PER_CHUNK]> + ExactSizeIterator + 'a {
+pub fn hash256_iter(
+    values: &[Hash256],
+) -> impl Iterator<Item = [u8; BYTES_PER_CHUNK]> + ExactSizeIterator + '_ {
     values.iter().copied().map(Hash256::to_fixed_bytes)
 }
 
-pub fn u64_iter<'a>(
-    values: &'a [u64],
-) -> impl Iterator<Item = [u8; BYTES_PER_CHUNK]> + ExactSizeIterator + 'a {
+pub fn u64_iter(
+    values: &[u64],
+) -> impl Iterator<Item = [u8; BYTES_PER_CHUNK]> + ExactSizeIterator + '_ {
     let type_size = size_of::<u64>();
     let vals_per_chunk = BYTES_PER_CHUNK / type_size;
     values.chunks(vals_per_chunk).map(move |xs| {

consensus/proto_array/src/ssz_container.rs

@@ -4,7 +4,6 @@ use crate::{
 };
 use ssz_derive::{Decode, Encode};
 use std::collections::HashMap;
-use std::iter::FromIterator;
 use types::{Epoch, Hash256};
 
 #[derive(Encode, Decode)]
@@ -41,7 +40,7 @@ impl From<SszContainer> for ProtoArrayForkChoice {
             justified_epoch: from.justified_epoch,
             finalized_epoch: from.finalized_epoch,
             nodes: from.nodes,
-            indices: HashMap::from_iter(from.indices.into_iter()),
+            indices: from.indices.into_iter().collect::<HashMap<_, _>>(),
         };
 
         Self {

consensus/ssz_derive/src/lib.rs

@@ -14,9 +14,7 @@ use syn::{parse_macro_input, DeriveInput};
 ///
 /// # Panics
 /// Any unnamed struct field (like in a tuple struct) will raise a panic at compile time.
-fn get_serializable_named_field_idents<'a>(
-    struct_data: &'a syn::DataStruct,
-) -> Vec<&'a syn::Ident> {
+fn get_serializable_named_field_idents(struct_data: &syn::DataStruct) -> Vec<&syn::Ident> {
     struct_data
         .fields
         .iter()
@@ -35,7 +33,7 @@ fn get_serializable_named_field_idents<'a>(
 
 /// Returns a Vec of `syn::Type` for each named field in the struct, whilst filtering out fields
 /// that should not be serialized.
-fn get_serializable_field_types<'a>(struct_data: &'a syn::DataStruct) -> Vec<&'a syn::Type> {
+fn get_serializable_field_types(struct_data: &syn::DataStruct) -> Vec<&syn::Type> {
     struct_data
         .fields
         .iter()

consensus/state_processing/src/per_block_processing/signature_sets.rs

@@ -44,10 +44,10 @@ impl From<BeaconStateError> for Error {
 }
 
 /// Helper function to get a public key from a `state`.
-pub fn get_pubkey_from_state<'a, T>(
-    state: &'a BeaconState<T>,
+pub fn get_pubkey_from_state<T>(
+    state: &BeaconState<T>,
     validator_index: usize,
-) -> Option<Cow<'a, PublicKey>>
+) -> Option<Cow<PublicKey>>
 where
     T: EthSpec,
 {

consensus/state_processing/src/per_block_processing/tests.rs

@@ -391,7 +391,7 @@ fn invalid_attestation_wrong_justified_checkpoint() {
                     root: Hash256::zero(),
                 },
                 attestation: Checkpoint {
-                    epoch: Epoch::from(0 as u64),
+                    epoch: Epoch::from(0_u64),
                     root: Hash256::zero(),
                 },
                 is_current: true,
@@ -877,7 +877,7 @@ fn invalid_proposer_slashing_proposal_epoch_mismatch() {
         Err(BlockProcessingError::ProposerSlashingInvalid {
             index: 0,
             reason: ProposerSlashingInvalid::ProposalSlotMismatch(
-                Slot::from(0 as u64),
+                Slot::from(0_u64),
                 Slot::from(128 as u64)
             )
         })

consensus/tree_hash_derive/src/lib.rs

@@ -10,7 +10,7 @@ use syn::{parse_macro_input, Attribute, DeriveInput, Meta};
 ///
 /// # Panics
 /// Any unnamed struct field (like in a tuple struct) will raise a panic at compile time.
-fn get_hashable_fields<'a>(struct_data: &'a syn::DataStruct) -> Vec<&'a syn::Ident> {
+fn get_hashable_fields(struct_data: &syn::DataStruct) -> Vec<&syn::Ident> {
     get_hashable_fields_and_their_caches(struct_data)
         .into_iter()
         .map(|(ident, _, _)| ident)
@@ -18,9 +18,9 @@ fn get_hashable_fields<'a>(struct_data: &'a syn::DataStruct) -> Vec<&'a syn::Ide
 }
 
 /// Return a Vec of the hashable fields of a struct, and each field's type and optional cache field.
-fn get_hashable_fields_and_their_caches<'a>(
-    struct_data: &'a syn::DataStruct,
-) -> Vec<(&'a syn::Ident, syn::Type, Option<syn::Ident>)> {
+fn get_hashable_fields_and_their_caches(
+    struct_data: &syn::DataStruct,
+) -> Vec<(&syn::Ident, syn::Type, Option<syn::Ident>)> {
     struct_data
         .fields
         .iter()

consensus/types/src/beacon_block.rs

@@ -68,7 +68,7 @@ impl<T: EthSpec> BeaconBlock<T> {
         };
         let indexed_attestation: IndexedAttestation<T> = IndexedAttestation {
             attesting_indices: VariableList::new(vec![
-                0 as u64;
+                0_u64;
                 T::MaxValidatorsPerCommittee::to_usize()
             ])
             .unwrap(),

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

@@ -69,7 +69,7 @@ impl TestingAttestationDataBuilder {
             }
             AttestationTestTask::WrongJustifiedCheckpoint => {
                 source = Checkpoint {
-                    epoch: Epoch::from(0 as u64),
+                    epoch: Epoch::from(0_u64),
                     root: Hash256::zero(),
                 }
             }