Update Rust nightly

Supersedes #368.

Adds exceptions for unwrap_or_default due to preference against Default's
ambiguity.

.github/nightly-version

@@ -1 +1 @@
-nightly-2023-08-01
+nightly-2023-09-01

coordinator/tributary/src/mempool.rs

@@ -35,6 +35,7 @@ impl<D: Db, T: TransactionTrait> Mempool<D, T> {
     let tx_hash = tx.hash();
     let transaction_key = self.transaction_key(&tx_hash);
     let current_mempool_key = self.current_mempool_key();
+    #[allow(clippy::unwrap_or_default)]
     let mut current_mempool = self.db.get(&current_mempool_key).unwrap_or(vec![]);
 
     let mut txn = self.db.txn();
@@ -225,6 +226,7 @@ impl<D: Db, T: TransactionTrait> Mempool<D, T> {
   pub(crate) fn remove(&mut self, tx: &[u8; 32]) {
     let transaction_key = self.transaction_key(tx);
     let current_mempool_key = self.current_mempool_key();
+    #[allow(clippy::unwrap_or_default)]
     let current_mempool = self.db.get(&current_mempool_key).unwrap_or(vec![]);
 
     let mut i = 0;

coordinator/tributary/src/provided.rs

@@ -77,6 +77,7 @@ impl<D: Db, T: Transaction> ProvidedTransactions<D, T> {
     }
 
     let current_provided_key = self.current_provided_key();
+    #[allow(clippy::unwrap_or_default)]
     let mut currently_provided = self.db.get(&current_provided_key).unwrap_or(vec![]);
 
     let mut txn = self.db.txn();

coordinator/tributary/tendermint/src/message_log.rs

@@ -19,7 +19,10 @@ impl<N: Network> MessageLog<N> {
   // Returns true if it's a new message
   pub(crate) fn log(&mut self, signed: SignedMessageFor<N>) -> Result<bool, TendermintError<N>> {
     let msg = &signed.msg;
+    // Clarity, and safety around default != new edge cases
+    #[allow(clippy::unwrap_or_default)]
     let round = self.log.entry(msg.round).or_insert_with(HashMap::new);
+    #[allow(clippy::unwrap_or_default)]
     let msgs = round.entry(msg.sender).or_insert_with(HashMap::new);
 
     // Handle message replays without issue. It's only multiple messages which is malicious

processor/src/scheduler.rs

@@ -179,6 +179,7 @@ impl<N: Network> Scheduler<N> {
 
     let mut add_plan = |payments| {
       let amount = payment_amounts(&payments);
+      #[allow(clippy::unwrap_or_default)]
       self.queued_plans.entry(amount).or_insert(VecDeque::new()).push_back(payments);
       amount
     };
@@ -394,6 +395,7 @@ impl<N: Network> Scheduler<N> {
       return;
     }
 
+    #[allow(clippy::unwrap_or_default)]
     self.plans.entry(actual).or_insert(VecDeque::new()).push_back(payments);
 
     // TODO: This shows how ridiculous the serialize function is

substrate/client/src/serai/mod.rs

@@ -149,6 +149,7 @@ impl Serai {
     block: [u8; 32],
   ) -> Result<Option<R>, SeraiError> {
     let storage = self.0.storage();
+    #[allow(clippy::unwrap_or_default)]
     let address = subxt::dynamic::storage(pallet, name, keys.unwrap_or(vec![]));
     debug_assert!(storage.validate(&address).is_ok(), "invalid storage address");