Apply clippy fixes

Author: jayvdb

src/fs/file.rs

@@ -696,7 +696,7 @@ impl LockGuard<State> {
         // file. This call should not block because it doesn't touch the actual file on disk.
         if pos == SeekFrom::Current(0) {
             // Poll the internal file cursor.
-            let internal = (&*self.file).seek(SeekFrom::Current(0))?;
+            let internal = (&*self.file).stream_position()?;
 
             // Factor in the difference caused by caching.
             let actual = match self.mode {
@@ -714,7 +714,7 @@ impl LockGuard<State> {
                 if let Some(new) = (start as i64).checked_add(diff) {
                     if 0 <= new && new <= self.cache.len() as i64 {
                         // Poll the internal file cursor.
-                        let internal = (&*self.file).seek(SeekFrom::Current(0))?;
+                        let internal = (&*self.file).stream_position()?;
 
                         // Adjust the current position in the read cache.
                         self.mode = Mode::Reading(new as usize);

src/future/poll_fn.rs

@@ -44,6 +44,6 @@ where
     type Output = T;
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<T> {
-        (&mut self.f)(cx)
+        (self.f)(cx)
     }
 }

src/io/buf_read/lines.rs

@@ -50,7 +50,7 @@ impl<R: BufRead> Stream for Lines<R> {
                 this.buf.pop();
             }
         }
-        Poll::Ready(Some(Ok(mem::replace(this.buf, String::new()))))
+        Poll::Ready(Some(Ok(mem::take(this.buf))))
     }
 }
 
@@ -62,7 +62,7 @@ pub fn read_line_internal<R: BufRead + ?Sized>(
     read: &mut usize,
 ) -> Poll<io::Result<usize>> {
     let ret = futures_core::ready!(read_until_internal(reader, cx, b'\n', bytes, read));
-    if str::from_utf8(&bytes).is_err() {
+    if str::from_utf8(bytes).is_err() {
         Poll::Ready(ret.and_then(|_| {
             Err(io::Error::new(
                 io::ErrorKind::InvalidData,

src/io/buf_read/mod.rs

@@ -136,7 +136,7 @@ pub trait BufReadExt: BufRead {
     {
         ReadLineFuture {
             reader: self,
-            bytes: unsafe { mem::replace(buf.as_mut_vec(), Vec::new()) },
+            bytes: unsafe { std::mem::take(buf.as_mut_vec()) },
             buf,
             read: 0,
         }

src/io/buf_read/read_line.rs

@@ -29,7 +29,7 @@ impl<T: BufRead + Unpin + ?Sized> Future for ReadLineFuture<'_, T> {
         let reader = Pin::new(reader);
 
         let ret = futures_core::ready!(read_until_internal(reader, cx, b'\n', bytes, read));
-        if str::from_utf8(&bytes).is_err() {
+        if str::from_utf8(bytes).is_err() {
             Poll::Ready(ret.and_then(|_| {
                 Err(io::Error::new(
                     io::ErrorKind::InvalidData,

src/io/buf_read/split.rs

@@ -46,6 +46,6 @@ impl<R: BufRead> Stream for Split<R> {
         if this.buf[this.buf.len() - 1] == *this.delim {
             this.buf.pop();
         }
-        Poll::Ready(Some(Ok(mem::replace(this.buf, vec![]))))
+        Poll::Ready(Some(Ok(mem::take(this.buf))))
     }
 }

src/io/read/chain.rs

@@ -144,7 +144,7 @@ impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
         let this = self.project();
         if !*this.done_first {
             match futures_core::ready!(this.first.poll_fill_buf(cx)) {
-                Ok(buf) if buf.is_empty() => {
+                Ok([]) => {
                     *this.done_first = true;
                 }
                 Ok(buf) => return Poll::Ready(Ok(buf)),

src/io/read/mod.rs

@@ -168,7 +168,7 @@ pub trait ReadExt: Read {
         let start_len = buf.len();
         ReadToStringFuture {
             reader: self,
-            bytes: unsafe { mem::replace(buf.as_mut_vec(), Vec::new()) },
+            bytes: unsafe { mem::take(buf.as_mut_vec()) },
             buf,
             start_len,
         }

src/io/read/read_exact.rs

@@ -20,7 +20,7 @@ impl<T: Read + Unpin + ?Sized> Future for ReadExactFuture<'_, T> {
 
         while !buf.is_empty() {
             let n = futures_core::ready!(Pin::new(&mut *reader).poll_read(cx, buf))?;
-            let (_, rest) = mem::replace(buf, &mut []).split_at_mut(n);
+            let (_, rest) = mem::take(buf).split_at_mut(n);
             *buf = rest;
 
             if n == 0 {

src/io/read/read_to_string.rs

@@ -29,7 +29,7 @@ impl<T: Read + Unpin + ?Sized> Future for ReadToStringFuture<'_, T> {
         let reader = Pin::new(reader);
 
         let ret = futures_core::ready!(read_to_end_internal(reader, cx, bytes, *start_len));
-        if str::from_utf8(&bytes).is_err() {
+        if str::from_utf8(bytes).is_err() {
             Poll::Ready(ret.and_then(|_| {
                 Err(io::Error::new(
                     io::ErrorKind::InvalidData,