fix clippy (#1737)

ci/azure-clippy.yml

@@ -12,5 +12,5 @@ jobs:
         cargo clippy --version
       displayName: Install clippy
     - script: |
-        cargo clippy --all --all-features -- -A clippy::mutex-atomic
+        cargo clippy --all --all-features -- -A clippy::mutex-atomic -A clippy::needless-doctest-main
       displayName: cargo clippy --all

tokio/src/io/async_read.rs

@@ -57,6 +57,11 @@ pub trait AsyncRead {
     ///
     /// This function is called from [`poll_read_buf`].
     ///
+    /// # Safety
+    ///
+    /// Implementations that return `false` must never read from data slices
+    /// that they did not write to.
+    ///
     /// [`io::Read`]: std::io::Read
     /// [`poll_read_buf`]: #method.poll_read_buf
     unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [u8]) -> bool {

tokio/src/process/mod.rs

@@ -479,7 +479,7 @@ impl Command {
     /// will be called and the spawn operation will immediately return with a
     /// failure.
     ///
-    /// # Notes and Safety
+    /// # Safety
     ///
     /// This closure will be run in the context of the child process after a
     /// `fork`. This primarily means that any modifications made to memory on

tokio/src/runtime/current_thread/mod.rs

@@ -337,6 +337,8 @@ impl fmt::Debug for Scheduler {
 
 unsafe fn sched_clone_waker(ptr: *const ()) -> RawWaker {
     let s1 = ManuallyDrop::new(Arc::from_raw(ptr as *const Scheduler));
+
+    #[allow(clippy::redundant_clone)]
     let s2 = s1.clone();
 
     RawWaker::new(

tokio/src/runtime/thread_pool/worker.rs

@@ -358,8 +358,6 @@ where
         park: &mut impl Park<Unpark = P>,
         gone: &Cell<bool>,
     ) -> Result<bool, WorkerGone> {
-        debug_assert!(self.is_running());
-
         loop {
             let tick = self.tick_fetch_inc();
 
@@ -412,8 +410,6 @@ where
     }
 
     fn search_for_work(&mut self, gone: &Cell<bool>) -> Result<bool, WorkerGone> {
-        debug_assert!(self.is_searching());
-
         if let Some(task) = self.steal_work() {
             self.run_task(task, gone)?;
             Ok(true)
@@ -435,8 +431,6 @@ where
     }
 
     fn transition_from_searching(&mut self) {
-        debug_assert!(self.is_searching());
-
         self.owned().is_searching.set(false);
 
         if self.set().idle().transition_worker_from_searching() {

tokio/src/sync/watch.rs

@@ -298,7 +298,6 @@ impl<T: Clone> Receiver<T> {
 impl<T: Clone> futures_core::Stream for Receiver<T> {
     type Item = T;
 
-    #[allow(clippy::map_clone)] // false positive: https://github.com/rust-lang/rust-clippy/issues/3274
     fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> {
         use std::future::Future;
 
@@ -306,7 +305,7 @@ impl<T: Clone> futures_core::Stream for Receiver<T> {
         pin_mut!(fut);
 
         let item = ready!(fut.poll(cx));
-        Ready(item.map(|v_ref| v_ref.clone()))
+        Ready(item.map(|v_ref| v_ref))
     }
 }
 

tokio/src/timer/wheel/mod.rs

@@ -173,19 +173,7 @@ where
             if let Some(expiration) = self.levels[level].next_expiration(self.elapsed) {
                 // There cannot be any expirations at a higher level that happen
                 // before this one.
-                debug_assert!({
-                    let mut res = true;
-
-                    for l2 in (level + 1)..NUM_LEVELS {
-                        if let Some(e2) = self.levels[l2].next_expiration(self.elapsed) {
-                            if e2.deadline < expiration.deadline {
-                                res = false;
-                            }
-                        }
-                    }
-
-                    res
-                });
+                debug_assert!(self.no_expirations_before(level + 1, expiration.deadline));
 
                 return Some(expiration);
             }
@@ -194,6 +182,21 @@ where
         None
     }
 
+    /// Used for debug assertions
+    fn no_expirations_before(&self, start_level: usize, before: u64) -> bool {
+        let mut res = true;
+
+        for l2 in start_level..NUM_LEVELS {
+            if let Some(e2) = self.levels[l2].next_expiration(self.elapsed) {
+                if e2.deadline < before {
+                    res = false;
+                }
+            }
+        }
+
+        res
+    }
+
     pub(crate) fn poll_expiration(
         &mut self,
         expiration: &Expiration,