Deny warnings on CI (#378)

* Deny warnings on CI

* Fix some clippy warnings

Author: taiki-e

Diff for: .github/workflows/ci.yml

@@ -11,6 +11,8 @@ jobs:
   build_and_test:
     name: Build and test
     runs-on: ${{ matrix.os }}
+    env:
+      RUSTFLAGS: -Dwarnings
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
@@ -46,6 +48,8 @@ jobs:
   check_fmt_and_docs:
     name: Checking fmt and docs
     runs-on: ubuntu-latest
+    env:
+      RUSTFLAGS: -Dwarnings
     steps:
     - uses: actions/checkout@master
 
@@ -77,6 +81,9 @@ jobs:
   clippy_check:
     name: Clippy check
     runs-on: ubuntu-latest
+    # TODO: There is a lot of warnings
+    # env:
+    #   RUSTFLAGS: -Dwarnings
     steps:
       - uses: actions/checkout@v1
       - id: component

Diff for: src/io/timeout.rs

@@ -71,7 +71,7 @@ where
         }
 
         if this.timeout.poll(cx).is_ready() {
-            let err = Err(io::Error::new(io::ErrorKind::TimedOut, "future timed out").into());
+            let err = Err(io::Error::new(io::ErrorKind::TimedOut, "future timed out"));
             Poll::Ready(err)
         } else {
             Poll::Pending

Diff for: src/io/write/write_fmt.rs

@@ -32,15 +32,15 @@ impl<T: Write + Unpin + ?Sized> Future for WriteFmtFuture<'_, T> {
             buffer,
             ..
         } = &mut *self;
-        let mut buffer = buffer.as_mut().unwrap();
+        let buffer = buffer.as_mut().unwrap();
 
         // Copy the data from the buffer into the writer until it's done.
         loop {
             if *amt == buffer.len() as u64 {
                 futures_core::ready!(Pin::new(&mut **writer).poll_flush(cx))?;
                 return Poll::Ready(Ok(()));
             }
-            let i = futures_core::ready!(Pin::new(&mut **writer).poll_write(cx, &mut buffer))?;
+            let i = futures_core::ready!(Pin::new(&mut **writer).poll_write(cx, buffer))?;
             if i == 0 {
                 return Poll::Ready(Err(io::ErrorKind::WriteZero.into()));
             }

Diff for: src/net/addr.rs

@@ -210,7 +210,7 @@ impl ToSocketAddrs for str {
         impl Future<Output = Self::Iter>,
         ToSocketAddrsFuture<Self::Iter>
     ) {
-        if let Some(addr) = self.parse().ok() {
+        if let Ok(addr) = self.parse() {
             return ToSocketAddrsFuture::Ready(Ok(vec![addr].into_iter()));
         }
 

Diff for: src/path/path.rs

@@ -799,7 +799,7 @@ impl AsRef<Path> for String {
 
 impl AsRef<Path> for std::path::PathBuf {
     fn as_ref(&self) -> &Path {
-        Path::new(self.into())
+        Path::new(self)
     }
 }
 

Diff for: src/path/pathbuf.rs

@@ -5,7 +5,7 @@ use crate::path::Path;
 /// This struct is an async version of [`std::path::PathBuf`].
 ///
 /// [`std::path::Path`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Default)]
 pub struct PathBuf {
     inner: std::path::PathBuf,
 }
@@ -206,7 +206,7 @@ impl From<std::path::PathBuf> for PathBuf {
 
 impl Into<std::path::PathBuf> for PathBuf {
     fn into(self) -> std::path::PathBuf {
-        self.inner.into()
+        self.inner
     }
 }
 

Diff for: src/stream/exact_size_stream.rs

@@ -59,7 +59,7 @@ pub use crate::stream::Stream;
 /// #         }
 /// #     }
 /// # }
-/// # fn main() { async_std::task::block_on(async {
+/// # async_std::task::block_on(async {
 /// #
 /// impl ExactSizeStream for Counter {
 ///     // We can easily calculate the remaining number of iterations.
@@ -74,7 +74,6 @@ pub use crate::stream::Stream;
 ///
 /// assert_eq!(5, counter.len());
 /// # });
-/// # }
 /// ```
 #[cfg(feature = "unstable")]
 #[cfg_attr(feature = "docs", doc(cfg(unstable)))]

Diff for: src/stream/extend.rs

@@ -14,7 +14,7 @@ use crate::stream::IntoStream;
 /// ## Examples
 ///
 /// ```
-/// # fn main() { async_std::task::block_on(async {
+/// # async_std::task::block_on(async {
 /// #
 /// use async_std::prelude::*;
 /// use async_std::stream::{self, Extend};
@@ -25,7 +25,7 @@ use crate::stream::IntoStream;
 ///
 /// assert_eq!(v, vec![1, 2, 3, 3, 3]);
 /// #
-/// # }) }
+/// # })
 /// ```
 #[cfg(feature = "unstable")]
 #[cfg_attr(feature = "docs", doc(cfg(unstable)))]

Diff for: src/stream/from_fn.rs

@@ -30,7 +30,7 @@ pin_project! {
 /// # Examples
 ///
 /// ```
-/// # fn main() { async_std::task::block_on(async {
+/// # async_std::task::block_on(async {
 /// #
 /// use async_std::prelude::*;
 /// use async_std::sync::Mutex;
@@ -58,8 +58,7 @@ pin_project! {
 /// assert_eq!(s.next().await, Some(3));
 /// assert_eq!(s.next().await, None);
 /// #
-/// # }) }
-///
+/// # })
 /// ```
 pub fn from_fn<T, F, Fut>(f: F) -> FromFn<F, Fut, T>
 where

Diff for: src/stream/repeat_with.rs

@@ -29,7 +29,7 @@ pin_project! {
 /// Basic usage:
 ///
 /// ```
-/// # fn main() { async_std::task::block_on(async {
+/// # async_std::task::block_on(async {
 /// #
 /// use async_std::prelude::*;
 /// use async_std::stream;
@@ -42,13 +42,13 @@ pin_project! {
 /// assert_eq!(s.next().await, Some(1));
 /// assert_eq!(s.next().await, Some(1));
 /// assert_eq!(s.next().await, Some(1));
-/// # }) }
+/// # })
 /// ```
 ///
 /// Going finite:
 ///
 /// ```
-/// # fn main() { async_std::task::block_on(async {
+/// # async_std::task::block_on(async {
 /// #
 /// use async_std::prelude::*;
 /// use async_std::stream;
@@ -60,7 +60,7 @@ pin_project! {
 /// assert_eq!(s.next().await, Some(1));
 /// assert_eq!(s.next().await, Some(1));
 /// assert_eq!(s.next().await, None);
-/// # }) }
+/// # })
 /// ```
 pub fn repeat_with<F, Fut, A>(repeater: F) -> RepeatWith<F, Fut, A>
 where

Diff for: src/sync/barrier.rs

@@ -8,7 +8,7 @@ use crate::sync::Mutex;
 /// # Examples
 ///
 /// ```
-/// # fn main() { async_std::task::block_on(async {
+/// # async_std::task::block_on(async {
 /// #
 /// use async_std::sync::{Arc, Barrier};
 /// use async_std::task;
@@ -30,7 +30,6 @@ use crate::sync::Mutex;
 ///     handle.await;
 /// }
 /// # });
-/// # }
 /// ```
 #[cfg(feature = "unstable")]
 #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
@@ -120,7 +119,7 @@ impl Barrier {
     /// # Examples
     ///
     /// ```
-    /// # fn main() { async_std::task::block_on(async {
+    /// # async_std::task::block_on(async {
     /// #
     /// use async_std::sync::{Arc, Barrier};
     /// use async_std::task;
@@ -142,7 +141,6 @@ impl Barrier {
     ///     handle.await;
     /// }
     /// # });
-    /// # }
     /// ```
     pub async fn wait(&self) -> BarrierWaitResult {
         let mut lock = self.state.lock().await;
@@ -190,15 +188,14 @@ impl BarrierWaitResult {
     /// # Examples
     ///
     /// ```
-    /// # fn main() { async_std::task::block_on(async {
+    /// # async_std::task::block_on(async {
     /// #
     /// use async_std::sync::Barrier;
     ///
     /// let barrier = Barrier::new(1);
     /// let barrier_wait_result = barrier.wait().await;
     /// println!("{:?}", barrier_wait_result.is_leader());
     /// # });
-    /// # }
     /// ```
     pub fn is_leader(&self) -> bool {
         self.0

Diff for: src/task/yield_now.rs

@@ -18,13 +18,13 @@ use std::pin::Pin;
 /// Basic usage:
 ///
 /// ```
-/// # fn main() { async_std::task::block_on(async {
+/// # async_std::task::block_on(async {
 /// #
 /// use async_std::task;
 ///
 /// task::yield_now().await;
 /// #
-/// # }) }
+/// # })
 /// ```
 #[cfg(feature = "unstable")]
 #[cfg_attr(feature = "docs", doc(cfg(unstable)))]