Remove unnecessary trait bounds from the definition of combinators

Author: taiki-e

futures-test/src/future/pending_once.rs

@@ -11,7 +11,7 @@ use pin_utils::{unsafe_pinned, unsafe_unpinned};
 /// method.
 #[derive(Debug, Clone)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
-pub struct PendingOnce<Fut: Future> {
+pub struct PendingOnce<Fut> {
     future: Fut,
     polled_before: bool,
 }

futures-util/src/future/catch_unwind.rs

@@ -8,7 +8,7 @@ use std::panic::{catch_unwind, UnwindSafe, AssertUnwindSafe};
 /// Future for the [`catch_unwind`](super::FutureExt::catch_unwind) method.
 #[derive(Debug)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
-pub struct CatchUnwind<Fut> where Fut: Future {
+pub struct CatchUnwind<Fut> {
     future: Fut,
 }
 

futures-util/src/future/flatten.rs

@@ -9,7 +9,6 @@ use pin_utils::unsafe_pinned;
 #[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct Flatten<Fut>
     where Fut: Future,
-          Fut::Output: Future,
 {
     state: Chain<Fut, Fut::Output, ()>,
 }
@@ -29,7 +28,7 @@ impl<Fut> Flatten<Fut>
 
 impl<Fut> fmt::Debug for Flatten<Fut>
     where Fut: Future + fmt::Debug,
-          Fut::Output: Future + fmt::Debug,
+          Fut::Output: fmt::Debug,
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Flatten")

futures-util/src/future/fuse.rs

@@ -6,7 +6,7 @@ use pin_utils::unsafe_pinned;
 /// Future for the [`fuse`](super::FutureExt::fuse) method.
 #[derive(Debug)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
-pub struct Fuse<Fut: Future> {
+pub struct Fuse<Fut> {
     future: Option<Fut>,
 }
 

futures-util/src/future/inspect.rs

@@ -6,7 +6,7 @@ use pin_utils::{unsafe_pinned, unsafe_unpinned};
 /// Future for the [`inspect`](super::FutureExt::inspect) method.
 #[derive(Debug)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
-pub struct Inspect<Fut, F> where Fut: Future {
+pub struct Inspect<Fut, F> {
     future: Fut,
     f: Option<F>,
 }

futures-util/src/future/into_stream.rs

@@ -8,7 +8,7 @@ use pin_utils::unsafe_pinned;
 /// Stream for the [`into_stream`](super::FutureExt::into_stream) method.
 #[must_use = "streams do nothing unless polled"]
 #[derive(Debug)]
-pub struct IntoStream<Fut: Future> {
+pub struct IntoStream<Fut> {
     inner: Once<Fut>
 }
 

futures-util/src/io/buf_reader.rs

@@ -199,7 +199,7 @@ impl<R: AsyncRead> AsyncBufRead for BufReader<R> {
     }
 }
 
-impl<R: AsyncRead + fmt::Debug> fmt::Debug for BufReader<R> {
+impl<R: fmt::Debug> fmt::Debug for BufReader<R> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("BufReader")
             .field("reader", &self.inner)

futures-util/src/io/buf_writer.rs

@@ -156,7 +156,7 @@ impl<W: AsyncWrite> AsyncWrite for BufWriter<W> {
     }
 }
 
-impl<W: AsyncWrite + fmt::Debug> fmt::Debug for BufWriter<W> {
+impl<W: fmt::Debug> fmt::Debug for BufWriter<W> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("BufWriter")
             .field("writer", &self.inner)

futures-util/src/io/close.rs

@@ -7,7 +7,7 @@ use std::pin::Pin;
 /// Future for the [`close`](super::AsyncWriteExt::close) method.
 #[derive(Debug)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
-pub struct Close<'a, W: ?Sized + Unpin> {
+pub struct Close<'a, W: ?Sized> {
     writer: &'a mut W,
 }
 

futures-util/src/io/copy_into.rs

@@ -9,7 +9,7 @@ use pin_utils::unsafe_pinned;
 /// Future for the [`copy_into`](super::AsyncReadExt::copy_into) method.
 #[derive(Debug)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
-pub struct CopyInto<'a, R: AsyncRead, W: ?Sized> {
+pub struct CopyInto<'a, R, W: ?Sized> {
     inner: CopyBufInto<'a, BufReader<R>, W>,
 }