ci: enable clippy lints

azure-pipelines.yml

@@ -11,6 +11,12 @@ jobs:
     rust: $(nightly)
     name: rustfmt
 
+# Apply clippy lints to all crates
+- template: ci/azure-clippy.yml
+  parameters:
+    rust: $(nightly)
+    name: clippy
+
 # Test top level crate
 - template: ci/azure-test-stable.yml
   parameters:

ci/azure-clippy.yml

@@ -0,0 +1,16 @@
+jobs:
+- job: ${{ parameters.name }}
+  displayName: Clippy
+  pool:
+    vmImage: ubuntu-16.04
+  steps:
+    - template: azure-install-rust.yml
+      parameters:
+        rust_version: ${{ parameters.rust }}
+    - script: |
+        rustup component add clippy
+        cargo clippy --version
+      displayName: Install clippy
+    - script: |
+        cargo clippy --all --all-features -- -D clippy::all
+      displayName: cargo clippy --all

tokio-codec/src/bytes_codec.rs

@@ -4,7 +4,7 @@ use bytes::{BufMut, Bytes, BytesMut};
 use std::io;
 
 /// A simple `Codec` implementation that just ships bytes around.
-#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash, Default)]
 pub struct BytesCodec(());
 
 impl BytesCodec {
@@ -19,7 +19,7 @@ impl Decoder for BytesCodec {
     type Error = io::Error;
 
     fn decode(&mut self, buf: &mut BytesMut) -> Result<Option<BytesMut>, io::Error> {
-        if buf.len() > 0 {
+        if !buf.is_empty() {
             let len = buf.len();
             Ok(Some(buf.split_to(len)))
         } else {

tokio-codec/src/framed_read.rs

@@ -153,7 +153,7 @@ pub fn framed_read2_with_buffer<T>(inner: T, mut buf: BytesMut) -> FramedRead2<T
     FramedRead2 {
         inner,
         eof: false,
-        is_readable: buf.len() > 0,
+        is_readable: !buf.is_empty(),
         buffer: buf,
     }
 }

tokio-codec/src/lines_codec.rs

@@ -190,6 +190,12 @@ impl Encoder for LinesCodec {
     }
 }
 
+impl Default for LinesCodec {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 #[derive(Debug)]
 pub enum LinesCodecError {
     MaxLineLengthExceeded,

tokio-current-thread/src/lib.rs

@@ -348,7 +348,7 @@ impl<P: Park> CurrentThread<P> {
     }
 
     /// Bind `CurrentThread` instance with an execution context.
-    fn enter<'a>(&'a mut self) -> Entered<'a, P> {
+    fn enter(&mut self) -> Entered<'_, P> {
         Entered { executor: self }
     }
 
@@ -429,6 +429,12 @@ impl<P: Park> fmt::Debug for CurrentThread<P> {
     }
 }
 
+impl<P: Park + Default> Default for CurrentThread<P> {
+    fn default() -> Self {
+        CurrentThread::new_with_park(P::default())
+    }
+}
+
 // ===== impl Entered =====
 
 impl<'a, P: Park> Entered<'a, P> {
@@ -483,7 +489,7 @@ impl<'a, P: Park> Entered<'a, P> {
 
             self.tick();
 
-            if let Err(_) = self.executor.park.park() {
+            if self.executor.park.park().is_err() {
                 panic!("block_on park failed");
             }
         }
@@ -550,7 +556,7 @@ impl<'a, P: Park> Entered<'a, P> {
 
             match time {
                 Some((until, rem)) => {
-                    if let Err(_) = self.executor.park.park_timeout(rem) {
+                    if self.executor.park.park_timeout(rem).is_err() {
                         return Err(RunTimeoutError::new(false));
                     }
 
@@ -563,7 +569,7 @@ impl<'a, P: Park> Entered<'a, P> {
                     time = Some((until, until - now));
                 }
                 None => {
-                    if let Err(_) = self.executor.park.park() {
+                    if self.executor.park.park().is_err() {
                         return Err(RunTimeoutError::new(false));
                     }
                 }
@@ -790,6 +796,8 @@ impl CurrentRunner {
 
 unsafe fn hide_lt<'a>(p: *mut (dyn SpawnLocal + 'a)) -> *mut (dyn SpawnLocal + 'static) {
     use std::mem;
+    // false positive: https://github.com/rust-lang/rust-clippy/issues/2906
+    #[allow(clippy::transmute_ptr_to_ptr)]
     mem::transmute(p)
 }
 

tokio-current-thread/src/scheduler.rs

@@ -443,10 +443,8 @@ impl<U> Inner<U> {
         let tail = *self.tail_readiness.get();
         let next = (*tail).next_readiness.load(Acquire);
 
-        if tail == self.stub() {
-            if next.is_null() {
-                return false;
-            }
+        if tail == self.stub() && next.is_null() {
+            return false;
         }
 
         true
@@ -566,7 +564,7 @@ impl<U> List<U> {
 
         self.len += 1;
 
-        return ptr;
+        ptr
     }
 
     /// Pop an element from the front of the list
@@ -618,7 +616,7 @@ impl<U> List<U> {
 
         self.len -= 1;
 
-        return node;
+        node
     }
 }
 
@@ -773,7 +771,7 @@ impl<U> Drop for Node<U> {
 fn arc2ptr<T>(ptr: Arc<T>) -> *const T {
     let addr = &*ptr as *const T;
     mem::forget(ptr);
-    return addr;
+    addr
 }
 
 unsafe fn ptr2arc<T>(ptr: *const T) -> Arc<T> {

tokio-executor/src/global.rs

@@ -180,6 +180,8 @@ where
 
 unsafe fn hide_lt<'a>(p: *mut (dyn Executor + 'a)) -> *mut (dyn Executor + 'static) {
     use std::mem;
+    // false positive: https://github.com/rust-lang/rust-clippy/issues/2906
+    #[allow(clippy::transmute_ptr_to_ptr)]
     mem::transmute(p)
 }
 

tokio-executor/src/park.rs

@@ -218,6 +218,12 @@ impl Park for ParkThread {
     }
 }
 
+impl Default for ParkThread {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 // ===== impl UnparkThread =====
 
 impl Unpark for UnparkThread {

tokio-fs/src/file/open_options.rs

@@ -102,3 +102,9 @@ impl From<StdOpenOptions> for OpenOptions {
         OpenOptions(options)
     }
 }
+
+impl Default for OpenOptions {
+    fn default() -> Self {
+        Self::new()
+    }
+}

tokio-io/src/async_read.rs

@@ -62,8 +62,8 @@ pub trait AsyncRead {
     /// [`io::Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
     /// [`poll_read_buf`]: #method.poll_read_buf
     unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [u8]) -> bool {
-        for i in 0..buf.len() {
-            buf[i] = 0;
+        for x in buf {
+            *x = 0;
         }
 
         true

tokio-macros/src/lib.rs

@@ -66,15 +66,12 @@ pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
     let mut runtime = RuntimeType::Multi;
 
     for arg in args {
-        match arg {
-            syn::NestedMeta::Meta(syn::Meta::Word(ident)) => {
-                match ident.to_string().to_lowercase().as_str() {
-                    "multi_thread" => runtime = RuntimeType::Multi,
-                    "single_thread" => runtime = RuntimeType::Single,
-                    name => panic!("Unknown attribute {} is specified", name),
-                }
+        if let syn::NestedMeta::Meta(syn::Meta::Word(ident)) = arg {
+            match ident.to_string().to_lowercase().as_str() {
+                "multi_thread" => runtime = RuntimeType::Multi,
+                "single_thread" => runtime = RuntimeType::Single,
+                name => panic!("Unknown attribute {} is specified", name),
             }
-            _ => (),
         }
     }
 

tokio-reactor/src/lib.rs

@@ -2,6 +2,7 @@
 #![deny(missing_docs, missing_debug_implementations, rust_2018_idioms)]
 #![cfg_attr(test, deny(warnings))]
 #![doc(test(no_crate_inject, attr(deny(rust_2018_idioms))))]
+#![allow(clippy::trivially_copy_pass_by_ref)]
 
 //! Event loop that drives Tokio I/O resources.
 //!
@@ -322,7 +323,7 @@ impl Reactor {
                 "loop process - {} events, {}.{:03}s",
                 events,
                 dur.as_secs(),
-                dur.subsec_nanos() / 1_000_000
+                dur.subsec_millis()
             );
         }
 

tokio-reactor/src/registration.rs

@@ -114,7 +114,7 @@ impl Registration {
     where
         T: Evented,
     {
-        self.register2(io, || HandlePriv::try_current())
+        self.register2(io, HandlePriv::try_current)
     }
 
     /// Deregister the I/O resource from the reactor it is associated with.
@@ -416,6 +416,12 @@ impl Registration {
     }
 }
 
+impl Default for Registration {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 unsafe impl Send for Registration {}
 unsafe impl Sync for Registration {}
 

tokio-signal/src/registry.rs

@@ -76,9 +76,9 @@ impl<S: Storage> Registry<S> {
     /// Mark `event_id` as having been delivered, without broadcasting it to
     /// any listeners.
     fn record_event(&self, event_id: EventId) {
-        self.storage
-            .event_info(event_id)
-            .map(|event_info| event_info.pending.store(true, Ordering::SeqCst));
+        if let Some(event_info) = self.storage.event_info(event_id) {
+            event_info.pending.store(true, Ordering::SeqCst)
+        }
     }
 
     /// Broadcast all previously recorded events to their respective listeners.

tokio-sync/src/lib.rs

@@ -8,6 +8,7 @@
 #![cfg_attr(test, deny(warnings))]
 #![doc(test(no_crate_inject, attr(deny(rust_2018_idioms))))]
 #![feature(async_await)]
+#![allow(clippy::trivially_copy_pass_by_ref)]
 
 //! Asynchronous synchronization primitives.
 //!

tokio-sync/src/mpsc/bounded.rs

@@ -132,6 +132,7 @@ impl<T> Receiver<T> {
     }
 
     /// TODO: Dox
+    #[allow(clippy::needless_lifetimes)] // false positive: https://github.com/rust-lang/rust-clippy/issues/3988
     pub async fn recv(&mut self) -> Option<T> {
         use async_util::future::poll_fn;
 
@@ -204,6 +205,7 @@ impl<T> Sender<T> {
     /// ```
     /// unimplemented!();
     /// ```
+    #[allow(clippy::needless_lifetimes)] // false positive: https://github.com/rust-lang/rust-clippy/issues/3988
     pub async fn send(&mut self, value: T) -> Result<(), SendError> {
         use async_util::future::poll_fn;
 

tokio-sync/src/mpsc/unbounded.rs

@@ -93,6 +93,7 @@ impl<T> UnboundedReceiver<T> {
     }
 
     /// TODO: Dox
+    #[allow(clippy::needless_lifetimes)] // false positive: https://github.com/rust-lang/rust-clippy/issues/3988
     pub async fn recv(&mut self) -> Option<T> {
         use async_util::future::poll_fn;
 

tokio-sync/src/oneshot.rs

@@ -220,6 +220,7 @@ impl<T> Sender<T> {
     /// ```
     /// unimplemented!();
     /// ```
+    #[allow(clippy::needless_lifetimes)] // false positive: https://github.com/rust-lang/rust-clippy/issues/3988
     pub async fn closed(&mut self) {
         use async_util::future::poll_fn;
 
@@ -384,10 +385,10 @@ impl<T> Inner<T> {
                         None => Ready(Err(RecvError(()))),
                     }
                 } else {
-                    return Pending;
+                    Pending
                 }
             } else {
-                return Pending;
+                Pending
             }
         }
     }

tokio-sync/src/semaphore.rs

@@ -597,9 +597,9 @@ impl Permit {
         }
 
         match semaphore.poll_permit(Some((cx, self)))? {
-            Ready(v) => {
+            Ready(()) => {
                 self.state = PermitState::Acquired;
-                Ready(Ok(v))
+                Ready(Ok(()))
             }
             Pending => {
                 self.state = PermitState::Waiting;
@@ -671,6 +671,12 @@ impl Permit {
     }
 }
 
+impl Default for Permit {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 // ===== impl AcquireError ====
 
 impl AcquireError {
@@ -874,6 +880,7 @@ impl WaiterNode {
         NodeState::store(&self.state, Idle, Relaxed);
     }
 
+    #[allow(clippy::wrong_self_convention)]
     fn into_non_null(arc: Arc<WaiterNode>) -> NonNull<WaiterNode> {
         let ptr = Arc::into_raw(arc);
         unsafe { NonNull::new_unchecked(ptr as *mut _) }

tokio-sync/src/watch.rs

@@ -270,6 +270,7 @@ impl<T: Clone> Receiver<T> {
     /// Attempts to clone the latest value sent via the channel.
     ///
     /// This is equivalent to calling `Clone` on the value returned by `poll_ref`.
+    #[allow(clippy::map_clone)] // false positive: https://github.com/rust-lang/rust-clippy/issues/3274
     pub fn poll_next(&mut self, cx: &mut Context<'_>) -> Poll<Option<T>> {
         let item = ready!(self.poll_ref(cx));
         Ready(item.map(|v_ref| v_ref.clone()))
@@ -280,6 +281,7 @@ 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(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<T>> {
         let item = ready!(self.poll_ref(cx));
         Ready(item.map(|v_ref| v_ref.clone()))
@@ -376,7 +378,7 @@ impl<T> futures_sink::Sink<T> for Sender<T> {
     }
 
     fn start_send(self: Pin<&mut Self>, item: T) -> Result<(), Self::Error> {
-        let _ = self.as_ref().get_ref().broadcast(item)?;
+        self.as_ref().get_ref().broadcast(item)?;
         Ok(())
     }