New clippy nightly lints

[brooksprumo]

Problem

There are new clippy lints in nightly (as of version nightly-aarch64-apple-darwin - rustc 1.77.0-nightly (e51e98dde 2023-12-31)) that prevent us from upgrading our nightly version of Rust to the latest. Usually we upgrade both stable and nightly at the same time, but in #34607 we only upgraded stable.

All the new lints

solana-zk-token-sdk

warning: writing `&Vec` instead of `&[_]` involves a new object where a slice will do
  --> zk-token-sdk/src/instruction/batched_range_proof/mod.rs:62:22
   |
62 |         commitments: &Vec<&PedersenCommitment>,
   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `&[&PedersenCommitment]`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
   = note: `#[warn(clippy::ptr_arg)]` on by default

warning: writing `&Vec` instead of `&[_]` involves a new object where a slice will do
  --> zk-token-sdk/src/instruction/batched_range_proof/mod.rs:63:18
   |
63 |         amounts: &Vec<u64>,
   |                  ^^^^^^^^^ help: change this to: `&[u64]`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

warning: writing `&Vec` instead of `&[_]` involves a new object where a slice will do
  --> zk-token-sdk/src/instruction/batched_range_proof/mod.rs:64:22
   |
64 |         bit_lengths: &Vec<usize>,
   |                      ^^^^^^^^^^^ help: change this to: `&[usize]`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

warning: writing `&Vec` instead of `&[_]` involves a new object where a slice will do
  --> zk-token-sdk/src/instruction/batched_range_proof/mod.rs:65:19
   |
65 |         openings: &Vec<&PedersenOpening>,
   |                   ^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `&[&PedersenOpening]`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg

    Checking solana-clap-utils v1.18.0 (/Users/brooks/src/solana/clap-utils)
warning: `solana-zk-token-sdk` (lib) generated 4 warnings

solana-bpf-loader-program

warning: in a `match` scrutinee, avoid complex blocks or closures with blocks; instead, move the block or closure higher and bind it with a `let`
   --> programs/bpf_loader/src/syscalls/mem_ops.rs:227:39
    |
227 |           |s1_addr, s2_addr, chunk_len| {
    |  _______________________________________^
228 | |             let res = unsafe {
229 | |                 let s1 = slice::from_raw_parts(s1_addr, chunk_len);
230 | |                 let s2 = slice::from_raw_parts(s2_addr, chunk_len);
...   |
240 | |             Ok(0)
241 | |         },
    | |_________^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_conditions
    = note: `#[warn(clippy::blocks_in_conditions)]` on by default

warning: `solana-bpf-loader-program` (lib) generated 1 warning

solana-accounts-db

warning: this `let...else` may be rewritten with the `?` operator
  --> accounts-db/src/rolling_bit_field/iterators.rs:36:13
   |
36 | /             let Some(bit) = self.bit_range.next() else {
37 | |                 return None;
38 | |             };
   | |______________^ help: replace it with: `let bit = self.bit_range.next()?;`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#question_mark
   = note: `#[warn(clippy::question_mark)]` on by default

    Checking solana-rpc-client-api v1.18.0 (/Users/brooks/src/solana/rpc-client-api)
warning: `solana-accounts-db` (lib) generated 1 warning

solana-runtime

warning: in a `match` scrutinee, avoid complex blocks or closures with blocks; instead, move the block or closure higher and bind it with a `let`
   --> runtime/src/accounts/mod.rs:483:82
    |
483 |       let min_balance = match get_system_account_kind(payer_account).ok_or_else(|| {
    |  __________________________________________________________________________________^
484 | |         error_counters.invalid_account_for_fee += 1;
485 | |         TransactionError::InvalidAccountForFee
486 | |     })? {
    | |_____^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_conditions
    = note: `#[warn(clippy::blocks_in_conditions)]` on by default

warning: this `let...else` may be rewritten with the `?` operator
    --> runtime/src/bank.rs:3093:21
     |
3093 | /                     let Some(vote_account) = get_vote_account(&vote_pubkey) else {
3094 | |                         return None;
3095 | |                     };
     | |______________________^ help: replace it with: `let vote_account = get_vote_account(&vote_pubkey)?;`
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#question_mark
     = note: `#[warn(clippy::question_mark)]` on by default

warning: this `let...else` may be rewritten with the `?` operator
    --> runtime/src/bank.rs:4778:17
     |
4778 | /                 let Some((_, account)) = accounts.get(i) else {
4779 | |                     return None;
4780 | |                 };
     | |__________________^ help: replace it with: `let (_, account) = accounts.get(i)?;`
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#question_mark

    Checking solana-bench-streamer v1.18.0 (/Users/brooks/src/solana/bench-streamer)
warning: `solana-runtime` (lib) generated 3 warnings

solana-rpc

warning: writing `&mut Vec` instead of `&mut [_]` involves a new object where a slice will do
   --> rpc/src/optimistically_confirmed_bank_tracker.rs:238:16
    |
238 |         roots: &mut Vec<Slot>,
    |                ^^^^^^^^^^^^^^ help: change this to: `&mut [Slot]`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
    = note: `#[warn(clippy::ptr_arg)]` on by default

warning: `solana-rpc` (lib) generated 1 warning

solana-core

warning: writing `&Vec` instead of `&[_]` involves a new object where a slice will do
   --> core/src/banking_stage/consumer.rs:153:29
    |
153 |         packets_to_process: &Vec<Arc<ImmutableDeserializedPacket>>,
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `&[Arc<ImmutableDeserializedPacket>]`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
    = note: `#[warn(clippy::ptr_arg)]` on by default

warning: `solana-core` (lib) generated 1 warning

warning: unit tests in doctest are not executed
  --> core/tests/fork-selection.rs:15:5
   |
15 |   //! #[test]
   |  _____^
16 | | //! #[ignore]
17 | | //! fn test_all_partitions() {
   | |__________________________^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#test_attr_in_doctest
   = note: `#[warn(clippy::test_attr_in_doctest)]` on by default

warning: `solana-core` (test "fork-selection") generated 1 warning

solana-ledger-tool

warning: `flatten()` will run forever if the iterator repeatedly produces an `Err`
    --> ledger-tool/src/main.rs:2649:39
     |
2649 |                 for line in f.lines().flatten() {
     |                                       ^^^^^^^^^ help: replace with: `map_while(Result::ok)`
     |
note: this expression returning a `std::io::Lines` may produce an infinite number of `Err` in case of a read error
    --> ledger-tool/src/main.rs:2649:29
     |
2649 |                 for line in f.lines().flatten() {
     |                             ^^^^^^^^^
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#lines_filter_map_ok
     = note: `#[warn(clippy::lines_filter_map_ok)]` on by default

warning: `solana-ledger-tool` (bin "solana-ledger-tool" test) generated 1 warning

solana-validator

warning: in a `match` scrutinee, avoid complex blocks or closures with blocks; instead, move the block or closure higher and bind it with a `let`
   --> validator/src/dashboard.rs:223:38
    |
223 |                       match async move {
    |  ______________________________________^
224 | |                         let rpc_addr = admin_client.rpc_addr().await?;
225 | |                         let start_time = admin_client.start_time().await?;
226 | |                         Ok::<_, jsonrpc_core_client::RpcError>((rpc_addr, start_time))
227 | |                     }
    | |_____________________^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_conditions
    = note: `#[warn(clippy::blocks_in_conditions)]` on by default

warning: `solana-validator` (lib) generated 1 warning

Proposed Solution

Fix the new warnings.

[brooksprumo]

There are a few remaining lints left to fix.
@steviez would you be willing to fix the ones in ledger-tool?
@alessandrod would you be willing to fix the ones in bpf_loader?
The specific lints for both are in the PR's description, under the "All the new lints" section.

As you likely know, this is not high priority.

[steviez]

@steviez would you be willing to fix the ones in ledger-tool?

Can do, looks like it should be pretty quick so I can knock it at some point today

[brooksprumo]

Closing. All the lints have now been resolved.