Update Rust toolchain to 1.78.0

Cargo.lock was updated to version 4 manually.
All Git refs in our Cargo.lock appear to be encoded correctly.
See:
- rust-lang/cargo#12280
- rust-lang/cargo#12852

The clippy::incompatible_msrv lint may be useful in the future.
We currently do not specify rust-version in Cargo.toml.
Our libraries are not designed to be used outside Grandine.
rust-toolchain.toml makes rust-version redundant for builds inside this repository.
See:
- https://doc.rust-lang.org/1.78.0/cargo/reference/manifest.html#the-rust-version-field
- https://rust-lang.github.io/rust-clippy/rust-1.78.0/#/incompatible_msrv

The clippy::lint_groups_priority lint produces false positives:
- rust-lang/cargo#12918 (comment)
- rust-lang/rust-clippy#12270
Luckily, lints inherited from a workspace do not trigger it.
The issue appears to be fixed in rust-lang/rust-clippy#12827.

The reason public functions trigger clippy::single_call_fn is actually our setting of avoid-breaking-exported-api.
We assumed it was a bug.

Cargo.toml

@@ -88,6 +88,7 @@ let_underscore_drop                    = 'warn'
 macro_use_extern_crate                 = 'warn'
 meta_variable_misuse                   = 'warn'
 non_ascii_idents                       = 'warn'
+non_local_definitions                  = 'warn'
 trivial_casts                          = 'warn'
 trivial_numeric_casts                  = 'warn'
 unit_bindings                          = 'warn'
@@ -140,7 +141,7 @@ wildcard_dependencies   = 'warn'
 #
 # - `clippy::single_call_fn`.
 #   It's unidiomatic and conflicts with lints like `clippy::too_many_lines`.
-#   Public functions are not exempt from it as of Rust 1.77.2.
+#   Public functions are not exempt from it if `avoid-breaking-exported-api` is `false`.
 #
 # - `clippy::std_instead_of_alloc`
 #   It would require adding `extern crate alloc;` everywhere.

benches/benches/hashing.rs

@@ -89,7 +89,7 @@ fn main() {
     criterion.final_summary();
 }
 
-// Arrays of arbitrary length do not implement `Default` as of Rust 1.77.2.
+// Arrays of arbitrary length do not implement `Default` as of Rust 1.78.0.
 // See <https://github.com/rust-lang/rust/issues/61415>.
 // We work around that by using `PublicKeyBytes` and `SignatureBytes` instead.
 

clippy.toml

@@ -1,9 +1,12 @@
 avoid-breaking-exported-api = false
 doc-valid-idents = [
+    '..',
     'Eth1Data',
     'PoS',
     'PoW',
     'RocksDB',
+    'UPnP',
+    'Web3Signer',
 ]
 # There appears to be no way to disallow an entire module.
 # There is an issue for it at <https://github.com/rust-lang/rust-clippy/issues/9489>.

fork_choice_control/src/mutator.rs

@@ -342,7 +342,7 @@ where
                             .blob_kzg_commitments()
                             .iter()
                             .copied()
-                            .map(helper_functions::misc::kzg_commitment_to_versioned_hash)
+                            .map(misc::kzg_commitment_to_versioned_hash)
                             .collect();
 
                         params = Some(ExecutionPayloadParams::Deneb {
@@ -2007,7 +2007,7 @@ where
 
         let mut gossip_ids = vec![];
 
-        // Use `drain_filter_polyfill` because `Vec::extract_if` is not stable as of Rust 1.77.2.
+        // Use `drain_filter_polyfill` because `Vec::extract_if` is not stable as of Rust 1.78.0.
         self.delayed_until_block.retain(|_, delayed| {
             let Delayed {
                 blocks,
@@ -2081,7 +2081,7 @@ where
 
         let mut gossip_ids = vec![];
 
-        // Use `HashMap::retain` because `HashMap::extract_if` is not stable as of Rust 1.77.2.
+        // Use `HashMap::retain` because `HashMap::extract_if` is not stable as of Rust 1.78.0.
         self.waiting_for_checkpoint_states
             .retain(|target, waiting| {
                 let prune = target.epoch < finalized_epoch;

grandine/src/grandine_args.rs

@@ -1,3 +1,7 @@
+// Adding backquotes to doc comments affects `--help` output.
+// `clap` derive macros preserve backquotes even if `verbatim_doc_comment` is disabled.
+#![allow(clippy::doc_markdown)]
+
 use core::{
     fmt::Display,
     net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr},

http_api/src/error.rs

@@ -158,7 +158,7 @@ impl Error {
         self.sources().format(": ")
     }
 
-    // `StdError::sources` is not stable as of Rust 1.77.2.
+    // `StdError::sources` is not stable as of Rust 1.78.0.
     fn sources(&self) -> impl Iterator<Item = &dyn StdError> {
         let mut error: Option<&dyn StdError> = Some(self);
 

http_api_utils/src/error.rs

@@ -37,7 +37,7 @@ impl Error {
         self.sources().format(": ")
     }
 
-    // `StdError::sources` is not stable as of Rust 1.77.2.
+    // `StdError::sources` is not stable as of Rust 1.78.0.
     fn sources(&self) -> impl Iterator<Item = &dyn StdError> {
         let mut error: Option<&dyn StdError> = Some(self);
 

p2p/src/network.rs

@@ -24,7 +24,7 @@ use eth2_libp2p::{
 };
 use fork_choice_control::P2pMessage;
 use futures::{
-    channel::mpsc::{self, Receiver, UnboundedReceiver, UnboundedSender},
+    channel::mpsc::{Receiver, UnboundedReceiver, UnboundedSender},
     future::FutureExt as _,
     select,
     stream::StreamExt as _,
@@ -174,8 +174,8 @@ impl<P: Preset> Network<P> {
             }
         }
 
-        let (network_to_service_tx, network_to_service_rx) = mpsc::unbounded();
-        let (service_to_network_tx, service_to_network_rx) = mpsc::unbounded();
+        let (network_to_service_tx, network_to_service_rx) = futures::channel::mpsc::unbounded();
+        let (service_to_network_tx, service_to_network_rx) = futures::channel::mpsc::unbounded();
 
         run_network_service(service, network_to_service_rx, service_to_network_tx);
 

rust-toolchain.toml

@@ -1,4 +1,4 @@
 [toolchain]
-channel = 'stable-2024-04-09'
+channel = 'stable-2024-05-02'
 profile = 'minimal'
 components = ['clippy', 'rustfmt']

ssz/src/merkle_tree.rs

@@ -237,7 +237,7 @@ impl<D: ArrayLength<H256>> MerkleTree<D> {
         // ```
         // See <https://oeis.org/A003817>.
         //
-        // `usize::saturating_shr` does not exist as of Rust 1.77.2.
+        // `usize::saturating_shr` does not exist as of Rust 1.78.0.
         let filled_left_subtree = usize::MAX
             .checked_shr(chunk_indices.start.leading_ones())
             .unwrap_or_default();

ssz/src/persistent_list.rs

@@ -568,6 +568,13 @@ impl<T, B: BundleSize<T>> Node<T, B> {
 
         loop {
             match node {
+                // False positive. See:
+                // - <https://github.com/rust-lang/rust-clippy/issues/12444>
+                // - <https://github.com/rust-lang/rust-clippy/issues/12460>
+                // - <https://github.com/rust-lang/rust-clippy/issues/12467>
+                // - <https://github.com/rust-lang/rust-clippy/issues/12749>
+                // - <https://github.com/rust-lang/rust-clippy/issues/12757>
+                #[allow(clippy::assigning_clones)]
                 Self::Internal {
                     left, left_height, ..
                 } if B::depth_of_length(length) <= *left_height => {

validator/src/api.rs

@@ -137,7 +137,7 @@ impl Error {
         self.sources().format(": ")
     }
 
-    // `StdError::sources` is not stable as of Rust 1.77.2.
+    // `StdError::sources` is not stable as of Rust 1.78.0.
     fn sources(&self) -> impl Iterator<Item = &dyn StdError> {
         let mut error: Option<&dyn StdError> = Some(self);
 

validator/src/own_sync_committee_subscriptions.rs

@@ -31,7 +31,7 @@ impl<P: Preset> OwnSyncCommitteeSubscriptions<P> {
         let next_period = current_period + 1;
         let next_period_start = misc::start_of_sync_committee_period::<P>(next_period);
 
-        if self.subscriptions.get(&current_period).is_none() {
+        if self.subscriptions.contains_key(&current_period) {
             let subscriptions = core::iter::repeat(current_epoch)
                 .zip(sync_committee_subscriptions(
                     state,
@@ -44,7 +44,7 @@ impl<P: Preset> OwnSyncCommitteeSubscriptions<P> {
             self.subscriptions.insert(current_period, subscriptions);
         }
 
-        if self.subscriptions.get(&next_period).is_none() {
+        if self.subscriptions.contains_key(&next_period) {
             let next_period_expiration = misc::start_of_sync_committee_period::<P>(next_period + 1);
 
             let mut rng = rand::thread_rng();