Fix warnings and compile errors on nightly (#6886)

Nightly has added a bunch of compiler and linter warnings. There is also
two dependencies that fail compilation on latest nightly due to using
the old `stdsimd` feature name. This PR fixes them.

libs/utils/src/auth.rs

@@ -1,7 +1,6 @@
 // For details about authentication see docs/authentication.md
 
 use arc_swap::ArcSwap;
-use serde;
 use std::{borrow::Cow, fmt::Display, fs, sync::Arc};
 
 use anyhow::Result;

libs/utils/src/completion.rs

@@ -4,7 +4,9 @@ use tokio_util::task::{task_tracker::TaskTrackerToken, TaskTracker};
 ///
 /// Can be cloned, moved and kept around in futures as "guard objects".
 #[derive(Clone)]
-pub struct Completion(TaskTrackerToken);
+pub struct Completion {
+    _token: TaskTrackerToken,
+}
 
 /// Barrier will wait until all clones of [`Completion`] have been dropped.
 #[derive(Clone)]
@@ -49,5 +51,5 @@ pub fn channel() -> (Completion, Barrier) {
     tracker.close();
 
     let token = tracker.token();
-    (Completion(token), Barrier(tracker))
+    (Completion { _token: token }, Barrier(tracker))
 }

libs/utils/src/http/endpoint.rs

@@ -9,7 +9,7 @@ use metrics::{register_int_counter, Encoder, IntCounter, TextEncoder};
 use once_cell::sync::Lazy;
 use routerify::ext::RequestExt;
 use routerify::{Middleware, RequestInfo, Router, RouterBuilder};
-use tracing::{self, debug, info, info_span, warn, Instrument};
+use tracing::{debug, info, info_span, warn, Instrument};
 
 use std::future::Future;
 use std::str::FromStr;

libs/utils/src/lsn.rs

@@ -415,7 +415,6 @@ mod tests {
 
     use super::*;
 
-    use serde::ser::Serialize;
     use serde_assert::{Deserializer, Serializer, Token, Tokens};
 
     #[test]

libs/utils/src/seqwait.rs

@@ -1,6 +1,6 @@
 #![warn(missing_docs)]
 
-use std::cmp::{Eq, Ordering, PartialOrd};
+use std::cmp::{Eq, Ordering};
 use std::collections::BinaryHeap;
 use std::fmt::Debug;
 use std::mem;
@@ -249,7 +249,6 @@ where
 mod tests {
     use super::*;
     use std::sync::Arc;
-    use std::time::Duration;
 
     impl MonotonicCounter<i32> for i32 {
         fn cnt_advance(&mut self, val: i32) {

libs/utils/src/simple_rcu.rs

@@ -221,7 +221,7 @@ impl RcuWaitList {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::sync::{Arc, Mutex};
+    use std::sync::Mutex;
     use std::time::Duration;
 
     #[tokio::test]

libs/utils/src/sync/heavier_once_cell.rs

@@ -239,7 +239,6 @@ mod tests {
     use std::{
         convert::Infallible,
         pin::{pin, Pin},
-        sync::atomic::{AtomicUsize, Ordering},
         time::Duration,
     };