chore(clippy): make clippy happy (#933)

Author: mattsse

crates/stages/src/stages/hashing_account.rs

@@ -235,8 +235,7 @@ mod tests {
                 &self,
                 blocks: Vec<SealedBlock>,
             ) -> Result<(), TestRunnerError> {
-                let mut blocks_iter = blocks.iter();
-                while let Some(block) = blocks_iter.next() {
+                for block in blocks.iter() {
                     self.tx.commit(|tx| {
                         insert_canonical_block(tx, block, true).unwrap();
                         Ok(())
@@ -248,10 +247,9 @@ mod tests {
 
             pub(crate) fn insert_accounts(
                 &self,
-                accounts: &Vec<(Address, Account)>,
+                accounts: &[(Address, Account)],
             ) -> Result<(), TestRunnerError> {
-                let mut accs_iter = accounts.iter();
-                while let Some((addr, acc)) = accs_iter.next() {
+                for (addr, acc) in accounts.iter() {
                     self.tx.commit(|tx| {
                         tx.put::<tables::PlainAccountState>(*addr, *acc)?;
                         Ok(())

crates/stages/src/stages/hashing_storage.rs

@@ -294,10 +294,10 @@ mod tests {
 
             self.tx.insert_headers(blocks.iter().map(|block| &block.header))?;
 
-            let mut iter = blocks.iter();
+            let iter = blocks.iter();
             let (mut transition_id, mut tx_id) = (0, 0);
 
-            while let Some(progress) = iter.next() {
+            for progress in iter {
                 // Insert last progress data
                 self.tx.commit(|tx| {
                     let key: BlockNumHash = (progress.number, progress.hash()).into();
@@ -423,9 +423,9 @@ mod tests {
             let mut storage_cursor = tx.cursor_dup_write::<tables::PlainStorageState>()?;
             let prev_entry = storage_cursor
                 .seek_by_key_subkey(tid_address.address(), entry.key)?
-                .and_then(|e| {
+                .map(|e| {
                     storage_cursor.delete_current().expect("failed to delete entry");
-                    Some(e)
+                    e
                 })
                 .unwrap_or(StorageEntry { key: entry.key, value: U256::from(0) });
             if hash {