diff --git a/harness/tests/integration_cases/test_raft.rs b/harness/tests/integration_cases/test_raft.rs
index 5356cd43c..180cc5e8c 100644
--- a/harness/tests/integration_cases/test_raft.rs
+++ b/harness/tests/integration_cases/test_raft.rs
@@ -917,7 +917,7 @@ fn test_dueling_candidates() {
     // enough log.
     nt.send(vec![new_message(3, 3, MessageType::MsgHup, 0)]);
 
-    let tests = vec![
+    let tests = [
         // role, term, committed, applied, last index.
         (StateRole::Follower, 2, (1, 0, 1)),
         (StateRole::Follower, 2, (1, 0, 1)),
@@ -968,7 +968,7 @@ fn test_dueling_pre_candidates() {
     // With pre-vote, it does not disrupt the leader.
     nt.send(vec![new_message(3, 3, MessageType::MsgHup, 0)]);
 
-    let tests = vec![
+    let tests = [
         // role, term, committed, applied, last index.
         (1, StateRole::Leader, 1, (1, 0, 1)),
         (2, StateRole::Follower, 1, (1, 0, 1)),
@@ -1242,7 +1242,7 @@ fn test_commit() {
 #[test]
 fn test_pass_election_timeout() {
     let l = default_logger();
-    let tests = vec![
+    let tests = [
         (5, 0f64, false),
         (10, 0.1, true),
         (13, 0.4, true),
@@ -1728,7 +1728,7 @@ fn test_all_server_stepdown() {
         (StateRole::Leader, StateRole::Follower, 3, 1, 1),
     ];
 
-    let tmsg_types = vec![MessageType::MsgRequestVote, MessageType::MsgAppend];
+    let tmsg_types = [MessageType::MsgRequestVote, MessageType::MsgAppend];
     let tterm = 3u64;
 
     for (i, (state, wstate, wterm, windex, entries)) in tests.drain(..).enumerate() {
@@ -3162,7 +3162,7 @@ fn test_add_node() -> Result<()> {
     let mut r = new_test_raft(1, vec![1], 10, 1, new_storage(), &l);
     r.apply_conf_change(&add_node(2))?;
     assert_iter_eq!(o r.prs().conf().voters().ids(),
-        vec![1, 2]
+        [1, 2]
     );
 
     Ok(())
@@ -3208,11 +3208,11 @@ fn test_remove_node() -> Result<()> {
     let l = default_logger();
     let mut r = new_test_raft(1, vec![1, 2], 10, 1, new_storage(), &l);
     r.apply_conf_change(&remove_node(2))?;
-    assert_iter_eq!(o r.prs().conf().voters().ids(), vec![1]);
+    assert_iter_eq!(o r.prs().conf().voters().ids(), [1]);
 
     // Removing all voters is not allowed.
     assert!(r.apply_conf_change(&remove_node(1)).is_err());
-    assert_iter_eq!(o r.prs().conf().voters().ids(), vec![1]);
+    assert_iter_eq!(o r.prs().conf().voters().ids(), [1]);
 
     Ok(())
 }
@@ -3223,8 +3223,8 @@ fn test_remove_node_itself() {
     let mut n1 = new_test_learner_raft(1, vec![1], vec![2], 10, 1, new_storage(), &l);
 
     assert!(n1.apply_conf_change(&remove_node(1)).is_err());
-    assert_iter_eq!(n1.prs().conf().learners(), vec![2]);
-    assert_iter_eq!(o n1.prs().conf().voters().ids(), vec![1]);
+    assert_iter_eq!(n1.prs().conf().learners(), [2]);
+    assert_iter_eq!(o n1.prs().conf().voters().ids(), [1]);
 }
 
 #[test]
@@ -3956,8 +3956,8 @@ fn test_restore_with_learner() {
     assert!(sm.restore(s.clone()));
     assert_eq!(sm.raft_log.last_index(), 11);
     assert_eq!(sm.raft_log.term(11).unwrap(), 11);
-    assert_iter_eq!(o sm.prs().conf().voters().ids(), vec![1, 2]);
-    assert_iter_eq!(sm.prs().conf().learners(), vec![3]);
+    assert_iter_eq!(o sm.prs().conf().voters().ids(), [1, 2]);
+    assert_iter_eq!(sm.prs().conf().learners(), [3]);
 
     let conf_state = s.get_metadata().get_conf_state();
     for node in &conf_state.voters {
@@ -3990,7 +3990,7 @@ fn test_restore_with_voters_outgoing() {
     );
     assert_iter_eq!(
         o sm.prs().conf().voters().ids(),
-        vec![1, 2, 3, 4]
+        [1, 2, 3, 4]
     );
     assert!(!sm.restore(s));
 }
@@ -4078,7 +4078,7 @@ fn test_add_learner() -> Result<()> {
     let mut n1 = new_test_raft(1, vec![1], 10, 1, new_storage(), &l);
     n1.apply_conf_change(&add_learner(2))?;
 
-    assert_iter_eq!(n1.prs().conf().learners(), vec![2]);
+    assert_iter_eq!(n1.prs().conf().learners(), [2]);
     assert!(n1.prs().conf().learners().contains(&2));
 
     Ok(())
@@ -4091,12 +4091,12 @@ fn test_remove_learner() -> Result<()> {
     let l = default_logger();
     let mut n1 = new_test_learner_raft(1, vec![1], vec![2], 10, 1, new_storage(), &l);
     n1.apply_conf_change(&remove_node(2))?;
-    assert_iter_eq!(o n1.prs().conf().voters().ids(), vec![1]);
+    assert_iter_eq!(o n1.prs().conf().voters().ids(), [1]);
     assert!(n1.prs().conf().learners().is_empty());
 
     // Remove all voters are not allowed.
     assert!(n1.apply_conf_change(&remove_node(1)).is_err());
-    assert_iter_eq!(o n1.prs().conf().voters().ids(), vec![1]);
+    assert_iter_eq!(o n1.prs().conf().voters().ids(), [1]);
     assert!(n1.prs().conf().learners().is_empty());
 
     Ok(())
@@ -5349,7 +5349,7 @@ fn test_election_after_change_priority() {
     // check state
     assert_eq!(network.peers[&1].state, StateRole::Follower, "peer 1 state");
 
-    let tests = vec![
+    let tests = [
         (1, 1, StateRole::Follower), //id, priority, state
         (1, 2, StateRole::Leader),
         (1, 3, StateRole::Leader),
@@ -5427,16 +5427,16 @@ fn test_uncommitted_entries_size_limit() {
     nt.send(vec![new_message(1, 1, MessageType::MsgHup, 0)]);
 
     // should return ok
-    nt.dispatch(vec![msg.clone()].to_vec()).unwrap();
+    nt.dispatch([msg.clone()]).unwrap();
 
     // then next proposal should be dropped
-    let result = nt.dispatch(vec![msg].to_vec());
+    let result = nt.dispatch([msg]);
     assert_eq!(result.unwrap_err(), raft::Error::ProposalDropped);
 
     // but entry with empty size should be accepted
     let entry = Entry::default();
     let empty_msg = new_message_with_entries(1, 1, MessageType::MsgPropose, vec![entry]);
-    nt.dispatch(vec![empty_msg].to_vec()).unwrap();
+    nt.dispatch([empty_msg]).unwrap();
 
     // after reduce, new proposal should be accepted
     let mut entry = Entry::default();
@@ -5453,18 +5453,18 @@ fn test_uncommitted_entries_size_limit() {
     let mut entry = Entry::default();
     entry.data = (b"hello world and raft" as &'static [u8]).into();
     let long_msg = new_message_with_entries(1, 1, MessageType::MsgPropose, vec![entry]);
-    nt.dispatch(vec![long_msg].to_vec()).unwrap();
+    nt.dispatch([long_msg]).unwrap();
 
     // but another huge one will be dropped
     let mut entry = Entry::default();
     entry.data = (b"hello world and raft" as &'static [u8]).into();
     let long_msg = new_message_with_entries(1, 1, MessageType::MsgPropose, vec![entry]);
-    nt.dispatch(vec![long_msg].to_vec()).unwrap_err();
+    nt.dispatch([long_msg]).unwrap_err();
 
     // entry with empty size should still be accepted
     let entry = Entry::default();
     let empty_msg = new_message_with_entries(1, 1, MessageType::MsgPropose, vec![entry]);
-    nt.dispatch(vec![empty_msg].to_vec()).unwrap();
+    nt.dispatch([empty_msg]).unwrap();
 }
 
 #[test]
diff --git a/proto/src/lib.rs b/proto/src/lib.rs
index 56ed74a73..3e29dbdeb 100644
--- a/proto/src/lib.rs
+++ b/proto/src/lib.rs
@@ -48,8 +48,8 @@ pub mod util {
     {
         fn from((voters, learners): (Iter1, Iter2)) -> Self {
             let mut conf_state = ConfState::default();
-            conf_state.mut_voters().extend(voters.into_iter());
-            conf_state.mut_learners().extend(learners.into_iter());
+            conf_state.mut_voters().extend(voters);
+            conf_state.mut_learners().extend(learners);
             conf_state
         }
     }
diff --git a/src/raft_log.rs b/src/raft_log.rs
index fcfcf32e7..0d4cf5aeb 100644
--- a/src/raft_log.rs
+++ b/src/raft_log.rs
@@ -883,7 +883,7 @@ mod test {
         assert_eq!(raft_log.committed, unstablesnapi);
         assert_eq!(raft_log.persisted, storagesnapi);
 
-        let tests = vec![
+        let tests = [
             // cannot get term from storage
             (storagesnapi, 0),
             // cannot get term from the gap between storage ents and unstable snapshot
@@ -916,7 +916,7 @@ mod test {
             raft_log.append(&[new_entry(offset + i, i)]);
         }
 
-        let tests = vec![
+        let tests = [
             (offset - 1, 0),
             (offset, 1),
             (offset + num / 2, num / 2),
@@ -1517,7 +1517,7 @@ mod test {
         let l = default_logger();
         let previous_ents = vec![new_entry(1, 1), new_entry(2, 2), new_entry(3, 3)];
         let previous_commit = 2u64;
-        let tests = vec![
+        let tests = [
             (3, 3, false),
             (1, 2, false), // never decrease
             (4, 0, true),  // commit out of range -> panic
@@ -1596,7 +1596,7 @@ mod test {
             raft_log.append(&[new_entry(i + offset, 0)]);
         }
         let first = offset + 1;
-        let tests = vec![
+        let tests = [
             (first - 2, first + 1, false, true),
             (first - 1, first + 1, false, true),
             (first, first, false, false),
diff --git a/src/tracker/progress.rs b/src/tracker/progress.rs
index b154c5773..20fe92251 100644
--- a/src/tracker/progress.rs
+++ b/src/tracker/progress.rs
@@ -261,7 +261,7 @@ mod tests {
 
     #[test]
     fn test_progress_is_paused() {
-        let tests = vec![
+        let tests = [
             (ProgressState::Probe, false, false),
             (ProgressState::Probe, true, true),
             (ProgressState::Replicate, false, false),
@@ -348,7 +348,7 @@ mod tests {
     #[test]
     fn test_progress_update() {
         let (prev_m, prev_n) = (3u64, 5u64);
-        let tests = vec![
+        let tests = [
             (prev_m - 1, prev_m, prev_n, false),
             (prev_m, prev_m, prev_n, false),
             (prev_m + 1, prev_m + 1, prev_n, true),