Cleanup stream traits (#487)

* Cleanup stream traits

* Fix docs

src/collections/binary_heap/from_stream.rs

@@ -1,16 +1,14 @@
 use std::collections::BinaryHeap;
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<T: Ord> FromStream<T> for BinaryHeap<T> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/collections/btree_map/from_stream.rs

@@ -1,16 +1,14 @@
 use std::collections::BTreeMap;
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<K: Ord, V> FromStream<(K, V)> for BTreeMap<K, V> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = (K, V)>>(
+    fn from_stream<'a, S: IntoStream<Item = (K, V)> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/collections/btree_set/from_stream.rs

@@ -1,16 +1,14 @@
 use std::collections::BTreeSet;
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<T: Ord> FromStream<T> for BTreeSet<T> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/collections/hash_map/from_stream.rs

@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use std::hash::{BuildHasher, Hash};
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<K, V, H> FromStream<(K, V)> for HashMap<K, V, H>
@@ -10,12 +11,9 @@ where
     H: BuildHasher + Default,
 {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = (K, V)>>(
+    fn from_stream<'a, S: IntoStream<Item = (K, V)> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/collections/hash_set/from_stream.rs

@@ -2,6 +2,7 @@ use std::collections::HashSet;
 use std::hash::{BuildHasher, Hash};
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<T, H> FromStream<T> for HashSet<T, H>
@@ -10,12 +11,9 @@ where
     H: BuildHasher + Default,
 {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/collections/linked_list/from_stream.rs

@@ -1,16 +1,14 @@
 use std::collections::LinkedList;
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<T> FromStream<T> for LinkedList<T> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/collections/vec_deque/from_stream.rs

@@ -1,16 +1,14 @@
 use std::collections::VecDeque;
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<T> FromStream<T> for VecDeque<T> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/fs/file_type.rs

@@ -40,7 +40,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn is_dir(&self) -> bool {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns `true` if this file type represents a regular file.
@@ -60,7 +60,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn is_file(&self) -> bool {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns `true` if this file type represents a symbolic link.
@@ -78,7 +78,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn is_symlink(&self) -> bool {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
     }
 }

src/fs/metadata.rs

@@ -78,7 +78,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn file_type(&self) -> FileType {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns `true` if this metadata is for a regular directory.
@@ -98,7 +98,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn is_dir(&self) -> bool {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns `true` if this metadata is for a regular file.
@@ -118,7 +118,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn is_file(&self) -> bool {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns the file size in bytes.
@@ -136,7 +136,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn len(&self) -> u64 {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns the permissions from this metadata.
@@ -154,7 +154,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn permissions(&self) -> Permissions {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns the last modification time.
@@ -177,7 +177,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn modified(&self) -> io::Result<SystemTime> {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns the last access time.
@@ -200,7 +200,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn accessed(&self) -> io::Result<SystemTime> {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Returns the creation time.
@@ -223,7 +223,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn created(&self) -> io::Result<SystemTime> {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
     }
 }

src/fs/permissions.rs

@@ -29,7 +29,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn readonly(&self) -> bool {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
 
         /// Configures the read-only flag.
@@ -50,7 +50,7 @@ cfg_docs! {
         /// # Ok(()) }) }
         /// ```
         pub fn set_readonly(&mut self, readonly: bool) {
-            unimplemented!()
+            unreachable!("this impl only appears in the rendered docs")
         }
     }
 }

src/fs/read_dir.rs

@@ -1,7 +1,7 @@
 use std::pin::Pin;
+use std::future::Future;
 
 use crate::fs::DirEntry;
-use crate::future::Future;
 use crate::io;
 use crate::path::Path;
 use crate::stream::Stream;

src/future/future/delay.rs

@@ -1,10 +1,10 @@
 use std::pin::Pin;
 use std::time::Duration;
+use std::future::Future;
 
 use futures_timer::Delay;
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::task::{Context, Poll};
 
 pin_project! {

src/future/future/flatten.rs

@@ -1,9 +1,8 @@
-use futures_core::ready;
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
-use crate::future::IntoFuture;
-use crate::task::{Context, Poll};
+use crate::future::{IntoFuture};
+use crate::task::{ready, Context, Poll};
 
 #[derive(Debug)]
 pub struct FlattenFuture<Fut1, Fut2> {

src/future/into_future.rs

@@ -1,4 +1,4 @@
-use crate::future::Future;
+use std::future::Future;
 
 /// Convert a type into a `Future`.
 ///

src/future/pending.rs

@@ -1,7 +1,7 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::task::{Context, Poll};
 
 /// Never resolves to a value.

src/future/poll_fn.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::task::{Context, Poll};
 
 /// Creates a new future wrapping around a function returning [`Poll`].

src/future/timeout.rs

@@ -2,11 +2,11 @@ use std::error::Error;
 use std::fmt;
 use std::pin::Pin;
 use std::time::Duration;
+use std::future::Future;
 
 use futures_timer::Delay;
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::task::{Context, Poll};
 
 /// Awaits a future or times out after a duration of time.

src/io/buf_read/read_line.rs

@@ -1,9 +1,9 @@
 use std::mem;
 use std::pin::Pin;
 use std::str;
+use std::future::Future;
 
 use super::read_until_internal;
-use crate::future::Future;
 use crate::io::{self, BufRead};
 use crate::task::{Context, Poll};
 

src/io/buf_read/read_until.rs

@@ -1,7 +1,7 @@
 use std::pin::Pin;
+use std::future::Future;
 
 use super::read_until_internal;
-use crate::future::Future;
 use crate::io::{self, BufRead};
 use crate::task::{Context, Poll};
 

src/io/buf_writer.rs

@@ -1,12 +1,11 @@
 use std::fmt;
 use std::pin::Pin;
 
-use futures_core::ready;
 use pin_project_lite::pin_project;
 
 use crate::io::write::WriteExt;
 use crate::io::{self, Seek, SeekFrom, Write};
-use crate::task::{Context, Poll};
+use crate::task::{Context, Poll, ready};
 
 const DEFAULT_CAPACITY: usize = 8 * 1024;
 

src/io/copy.rs

@@ -1,8 +1,8 @@
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::io::{self, BufRead, BufReader, Read, Write};
 use crate::task::{Context, Poll};
 

src/io/read/read.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Read};
 use crate::task::{Context, Poll};
 

src/io/read/read_exact.rs

@@ -1,7 +1,7 @@
 use std::mem;
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Read};
 use crate::task::{Context, Poll};
 

src/io/read/read_to_end.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Read};
 use crate::task::{Context, Poll};
 

src/io/read/read_to_string.rs

@@ -1,9 +1,9 @@
 use std::mem;
 use std::pin::Pin;
 use std::str;
+use std::future::Future;
 
 use super::read_to_end_internal;
-use crate::future::Future;
 use crate::io::{self, Read};
 use crate::task::{Context, Poll};
 

src/io/read/read_vectored.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, IoSliceMut, Read};
 use crate::task::{Context, Poll};
 

src/io/seek/seek.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Seek, SeekFrom};
 use crate::task::{Context, Poll};
 

src/io/stderr.rs

@@ -1,7 +1,7 @@
 use std::pin::Pin;
 use std::sync::Mutex;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Write};
 use crate::task::{spawn_blocking, Context, JoinHandle, Poll};
 

src/io/stdin.rs

@@ -1,7 +1,8 @@
 use std::pin::Pin;
 use std::sync::Mutex;
+use std::future::Future;
 
-use crate::future::{self, Future};
+use crate::future;
 use crate::io::{self, Read};
 use crate::task::{spawn_blocking, Context, JoinHandle, Poll};
 

src/io/stdout.rs

@@ -1,7 +1,7 @@
 use std::pin::Pin;
 use std::sync::Mutex;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Write};
 use crate::task::{spawn_blocking, Context, JoinHandle, Poll};
 

src/io/timeout.rs

@@ -1,11 +1,11 @@
 use std::pin::Pin;
 use std::task::{Context, Poll};
 use std::time::Duration;
+use std::future::Future;
 
 use futures_timer::Delay;
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::io;
 
 /// Awaits an I/O future or times out after a duration of time.

src/io/write/flush.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Write};
 use crate::task::{Context, Poll};
 

src/io/write/write.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Write};
 use crate::task::{Context, Poll};
 

src/io/write/write_all.rs

@@ -1,7 +1,7 @@
 use std::mem;
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Write};
 use crate::task::{Context, Poll};
 

src/io/write/write_fmt.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, Write};
 use crate::task::{Context, Poll};
 

src/io/write/write_vectored.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io::{self, IoSlice, Write};
 use crate::task::{Context, Poll};
 

src/net/addr.rs

@@ -2,8 +2,8 @@ use std::mem;
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
 use std::net::{SocketAddr, SocketAddrV4, SocketAddrV6};
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io;
 use crate::task::{spawn_blocking, Context, JoinHandle, Poll};
 

src/net/tcp/listener.rs

@@ -1,7 +1,8 @@
 use std::net::SocketAddr;
+use std::future::Future;
 use std::pin::Pin;
 
-use crate::future::{self, Future};
+use crate::future;
 use crate::io;
 use crate::net::driver::Watcher;
 use crate::net::{TcpStream, ToSocketAddrs};

src/option/from_stream.rs

@@ -11,12 +11,9 @@ where
     /// elements are taken, and `None` is returned. Should no `None`
     /// occur, a container with the values of each `Option` is returned.
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = Option<T>>>(
+    fn from_stream<'a, S: IntoStream<Item = Option<T>> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/os/unix/net/listener.rs

@@ -2,12 +2,13 @@
 
 use std::fmt;
 use std::pin::Pin;
+use std::future::Future;
 
 use mio_uds;
 
 use super::SocketAddr;
 use super::UnixStream;
-use crate::future::{self, Future};
+use crate::future;
 use crate::io;
 use crate::net::driver::Watcher;
 use crate::os::unix::io::{AsRawFd, FromRawFd, IntoRawFd, RawFd};

src/path/pathbuf.rs

@@ -242,36 +242,30 @@ impl AsRef<std::path::Path> for PathBuf {
 
 #[cfg(feature = "unstable")]
 impl<P: AsRef<Path>> stream::Extend<P> for PathBuf {
-    fn extend<'a, S: IntoStream<Item = P>>(
+    fn extend<'a, S: IntoStream<Item = P> + 'a>(
         &'a mut self,
         stream: S,
-    ) -> Pin<Box<dyn Future<Output = ()> + 'a>>
-    where
-        P: 'a,
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
         let stream = stream.into_stream();
 
-        //TODO: This can be added back in once this issue is resolved:
-        // https://github.com/rust-lang/rust/issues/58234
-        //self.reserve(stream.size_hint().0);
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
 
-        Box::pin(stream.for_each(move |item| self.push(item.as_ref())))
+            while let Some(item) = stream.next().await {
+                self.push(item.as_ref());
+            }
+        })
     }
 }
 
 #[cfg(feature = "unstable")]
 impl<'b, P: AsRef<Path> + 'b> FromStream<P> for PathBuf {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = P>>(
+    fn from_stream<'a, S: IntoStream<Item = P> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
-        let stream = stream.into_stream();
-
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         Box::pin(async move {
+            let stream = stream.into_stream();
             pin_utils::pin_mut!(stream);
 
             let mut out = Self::new();

src/prelude.rs

@@ -13,7 +13,7 @@
 
 cfg_std! {
     #[doc(no_inline)]
-    pub use crate::future::Future;
+    pub use std::future::Future;
     #[doc(no_inline)]
     pub use crate::stream::Stream;
 

src/result/from_stream.rs

@@ -11,12 +11,9 @@ where
     /// elements are taken, and the `Err` is returned. Should no `Err`
     /// occur, a container with the values of each `Result` is returned.
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = Result<T, E>>>(
+    fn from_stream<'a, S: IntoStream<Item = Result<T, E>> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/stream/extend.rs

@@ -34,9 +34,7 @@ pub trait Extend<A> {
     fn extend<'a, T: IntoStream<Item = A> + 'a>(
         &'a mut self,
         stream: T,
-    ) -> Pin<Box<dyn Future<Output = ()> + 'a>>
-    where
-        A: 'a;
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>>;
 }
 
 /// Extends a collection with the contents of a stream.
@@ -70,7 +68,6 @@ pub trait Extend<A> {
 pub async fn extend<'a, C, A, T>(collection: &mut C, stream: T)
 where
     C: Extend<A>,
-    A: 'a,
     T: IntoStream<Item = A> + 'a,
 {
     Extend::extend(collection, stream).await

src/stream/from_fn.rs

@@ -1,9 +1,9 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/from_iter.rs

@@ -18,8 +18,11 @@ pin_project! {
     }
 }
 
+/// Converts an iterator into a stream.
+///
 /// # Examples
-///```
+///
+/// ```
 /// # async_std::task::block_on(async {
 /// #
 /// use async_std::prelude::*;
@@ -34,8 +37,8 @@ pin_project! {
 /// assert_eq!(s.next().await, None);
 /// #
 /// # })
-///````
-pub fn from_iter<I: IntoIterator>(iter: I) -> FromIter<<I as std::iter::IntoIterator>::IntoIter> {
+/// ```
+pub fn from_iter<I: IntoIterator>(iter: I) -> FromIter<I::IntoIter> {
     FromIter {
         iter: iter.into_iter(),
     }

src/stream/from_stream.rs

@@ -1,7 +1,8 @@
-use super::IntoStream;
-
+use std::future::Future;
 use std::pin::Pin;
 
+use crate::stream::IntoStream;
+
 /// Conversion from a `Stream`.
 ///
 /// By implementing `FromStream` for a type, you define how it will be created from a stream.
@@ -15,6 +16,7 @@ use std::pin::Pin;
 ///
 /// ```
 /// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
+/// #
 /// use async_std::prelude::*;
 /// use async_std::stream::{self, FromStream};
 ///
@@ -23,13 +25,15 @@ use std::pin::Pin;
 /// let v = Vec::from_stream(five_fives).await;
 ///
 /// assert_eq!(v, vec![5, 5, 5, 5, 5]);
+/// #
 /// # Ok(()) }) }
 /// ```
 ///
 /// Using `collect` to  implicitly use `FromStream`
 ///
-///```
+/// ```
 /// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
+/// #
 /// use async_std::prelude::*;
 /// use async_std::stream;
 /// let five_fives = stream::repeat(5).take(5);
@@ -39,7 +43,7 @@ use std::pin::Pin;
 /// assert_eq!(v, vec![5, 5, 5, 5, 5]);
 /// #
 /// # Ok(()) }) }
-///```
+/// ```
 ///
 /// Implementing `FromStream` for your type:
 ///
@@ -68,7 +72,7 @@ use std::pin::Pin;
 /// impl FromStream<i32> for MyCollection {
 ///     fn from_stream<'a, S: IntoStream<Item = i32> + 'a>(
 ///         stream: S,
-///     ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>> {
+///     ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
 ///         let stream = stream.into_stream();
 ///
 ///         Box::pin(async move {
@@ -86,6 +90,7 @@ use std::pin::Pin;
 /// }
 ///
 /// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
+/// #
 /// // Now we can make a new stream...
 /// let stream = stream::repeat(5).take(5);
 ///
@@ -100,6 +105,7 @@ use std::pin::Pin;
 /// let c: MyCollection = stream.collect().await;
 ///
 /// assert_eq!(c.0, vec![5, 5, 5, 5, 5]);
+/// #
 /// # Ok(()) }) }
 ///```
 ///
@@ -115,6 +121,7 @@ pub trait FromStream<T> {
     ///
     /// ```
     /// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
+    /// #
     /// use async_std::prelude::*;
     /// use async_std::stream::{self, FromStream};
     ///
@@ -123,9 +130,10 @@ pub trait FromStream<T> {
     /// let v = Vec::from_stream(five_fives).await;
     ///
     /// assert_eq!(v, vec![5, 5, 5, 5, 5]);
+    /// #
     /// # Ok(()) }) }
     /// ```
     fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>;
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>>;
 }

src/stream/interval.rs

@@ -2,10 +2,10 @@ use std::pin::Pin;
 use std::task::{Context, Poll};
 use std::time::{Duration, Instant};
 
-use futures_core::future::Future;
-use futures_core::stream::Stream;
 use futures_timer::Delay;
 
+use crate::prelude::*;
+
 /// Creates a new stream that yields at a set interval.
 ///
 /// The stream first yields after `dur`, and continues to yield every

src/stream/product.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::stream::Stream;
 
 /// Trait to represent types that can be created by multiplying the elements of a stream.

src/stream/repeat_with.rs

@@ -1,9 +1,9 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/all.rs

@@ -1,7 +1,7 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/any.rs

@@ -1,7 +1,7 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/cmp.rs

@@ -1,10 +1,10 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
 use super::fuse::Fuse;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/eq.rs

@@ -1,9 +1,9 @@
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
 use super::fuse::Fuse;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/find.rs

@@ -1,7 +1,7 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/find_map.rs

@@ -1,8 +1,8 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
 use std::task::{Context, Poll};
+use std::future::Future;
 
-use crate::future::Future;
 use crate::stream::Stream;
 
 #[doc(hidden)]

src/stream/stream/fold.rs

@@ -1,9 +1,9 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/for_each.rs

@@ -1,9 +1,9 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/ge.rs

@@ -1,10 +1,10 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
 use super::partial_cmp::PartialCmpFuture;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/gt.rs

@@ -1,10 +1,10 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
 use super::partial_cmp::PartialCmpFuture;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/last.rs

@@ -1,8 +1,8 @@
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/le.rs

@@ -1,10 +1,10 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
 use super::partial_cmp::PartialCmpFuture;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/lt.rs

@@ -1,10 +1,10 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
 use super::partial_cmp::PartialCmpFuture;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/max_by.rs

@@ -1,9 +1,9 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/max_by_key.rs

@@ -1,9 +1,9 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/merge.rs

@@ -1,7 +1,6 @@
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
-use futures_core::Stream;
 use pin_project_lite::pin_project;
 
 use crate::prelude::*;

src/stream/stream/min.rs

@@ -1,10 +1,10 @@
 use std::cmp::{Ord, Ordering};
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/min_by.rs

@@ -1,9 +1,9 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/min_by_key.rs

@@ -1,9 +1,9 @@
 use std::cmp::Ordering;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/mod.rs

@@ -112,10 +112,10 @@ use std::cmp::Ordering;
 use std::marker::PhantomData;
 
 cfg_unstable! {
+    use std::future::Future;
     use std::pin::Pin;
     use std::time::Duration;
 
-    use crate::future::Future;
     use crate::stream::into_stream::IntoStream;
     use crate::stream::{FromStream, Product, Sum};
 

src/stream/stream/ne.rs

@@ -1,9 +1,9 @@
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
 use super::fuse::Fuse;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/next.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/nth.rs

@@ -1,7 +1,7 @@
 use std::pin::Pin;
 use std::task::{Context, Poll};
+use std::future::Future;
 
-use crate::future::Future;
 use crate::stream::Stream;
 
 #[doc(hidden)]

src/stream/stream/partial_cmp.rs

@@ -1,10 +1,10 @@
 use std::cmp::Ordering;
+use std::future::Future;
 use std::pin::Pin;
 
 use pin_project_lite::pin_project;
 
 use super::fuse::Fuse;
-use crate::future::Future;
 use crate::prelude::*;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};

src/stream/stream/position.rs

@@ -1,8 +1,8 @@
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/timeout.rs

@@ -2,11 +2,11 @@ use std::error::Error;
 use std::fmt;
 use std::pin::Pin;
 use std::time::Duration;
+use std::future::Future;
 
 use futures_timer::Delay;
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/try_fold.rs

@@ -1,9 +1,9 @@
 use std::marker::PhantomData;
 use std::pin::Pin;
+use std::future::Future;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/stream/try_for_each.rs

@@ -1,9 +1,9 @@
+use std::future::Future;
 use std::marker::PhantomData;
 use std::pin::Pin;
 
 use pin_project_lite::pin_project;
 
-use crate::future::Future;
 use crate::stream::Stream;
 use crate::task::{Context, Poll};
 

src/stream/sum.rs

@@ -1,6 +1,6 @@
+use std::future::Future;
 use std::pin::Pin;
 
-use crate::future::Future;
 use crate::stream::Stream;
 
 /// Trait to represent types that can be created by summing up a stream.
@@ -23,9 +23,9 @@ pub trait Sum<A = Self>: Sized {
         S: Stream<Item = A> + 'a;
 }
 
-use core::ops::Add;
-use core::num::Wrapping;
 use crate::stream::stream::StreamExt;
+use core::num::Wrapping;
+use core::ops::Add;
 
 macro_rules! integer_sum {
     (@impls $zero: expr, $($a:ty)*) => ($(
@@ -75,5 +75,5 @@ macro_rules! float_sum {
     );
 }
 
-integer_sum!{ i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
-float_sum!{ f32 f64 }
+integer_sum! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
+float_sum! { f32 f64 }

src/string/extend.rs

@@ -10,25 +10,32 @@ impl stream::Extend<char> for String {
         stream: S,
     ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
         let stream = stream.into_stream();
-
         self.reserve(stream.size_hint().0);
 
-        Box::pin(stream.for_each(move |c| self.push(c)))
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            while let Some(item) = stream.next().await {
+                self.push(item);
+            }
+        })
     }
 }
 
 impl<'b> stream::Extend<&'b char> for String {
     fn extend<'a, S: IntoStream<Item = &'b char> + 'a>(
         &'a mut self,
-        //TODO: Remove the underscore when uncommenting the body of this impl
-        _stream: S,
-    ) -> Pin<Box<dyn Future<Output = ()> + 'a>>
-    where
-        'b: 'a,
-    {
-        //TODO: This can be uncommented when `copied` is added to Stream/StreamExt
-        //Box::pin(stream.into_stream().copied())
-        unimplemented!()
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            while let Some(item) = stream.next().await {
+                self.push(*item);
+            }
+        })
     }
 }
 
@@ -36,11 +43,16 @@ impl<'b> stream::Extend<&'b str> for String {
     fn extend<'a, S: IntoStream<Item = &'b str> + 'a>(
         &'a mut self,
         stream: S,
-    ) -> Pin<Box<dyn Future<Output = ()> + 'a>>
-    where
-        'b: 'a,
-    {
-        Box::pin(stream.into_stream().for_each(move |s| self.push_str(s)))
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            while let Some(item) = stream.next().await {
+                self.push_str(item);
+            }
+        })
     }
 }
 
@@ -49,7 +61,15 @@ impl stream::Extend<String> for String {
         &'a mut self,
         stream: S,
     ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
-        Box::pin(stream.into_stream().for_each(move |s| self.push_str(&s)))
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            while let Some(item) = stream.next().await {
+                self.push_str(&item);
+            }
+        })
     }
 }
 
@@ -57,10 +77,15 @@ impl<'b> stream::Extend<Cow<'b, str>> for String {
     fn extend<'a, S: IntoStream<Item = Cow<'b, str>> + 'a>(
         &'a mut self,
         stream: S,
-    ) -> Pin<Box<dyn Future<Output = ()> + 'a>>
-    where
-        'b: 'a,
-    {
-        Box::pin(stream.into_stream().for_each(move |s| self.push_str(&s)))
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            while let Some(item) = stream.next().await {
+                self.push_str(&item);
+            }
+        })
     }
 }

src/string/from_stream.rs

@@ -1,16 +1,14 @@
 use std::borrow::Cow;
 use std::pin::Pin;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl FromStream<char> for String {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = char>>(
+    fn from_stream<'a, S: IntoStream<Item = char> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {
@@ -25,12 +23,9 @@ impl FromStream<char> for String {
 
 impl<'b> FromStream<&'b char> for String {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = &'b char>>(
+    fn from_stream<'a, S: IntoStream<Item = &'b char> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {
@@ -45,12 +40,9 @@ impl<'b> FromStream<&'b char> for String {
 
 impl<'b> FromStream<&'b str> for String {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = &'b str>>(
+    fn from_stream<'a, S: IntoStream<Item = &'b str> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {
@@ -65,12 +57,9 @@ impl<'b> FromStream<&'b str> for String {
 
 impl FromStream<String> for String {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = String>>(
+    fn from_stream<'a, S: IntoStream<Item = String> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {
@@ -85,12 +74,9 @@ impl FromStream<String> for String {
 
 impl<'b> FromStream<Cow<'b, str>> for String {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = Cow<'b, str>>>(
+    fn from_stream<'a, S: IntoStream<Item = Cow<'b, str>> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {

src/sync/mutex.rs

@@ -3,8 +3,8 @@ use std::fmt;
 use std::ops::{Deref, DerefMut};
 use std::pin::Pin;
 use std::sync::atomic::{AtomicBool, Ordering};
+use std::future::Future;
 
-use crate::future::Future;
 use crate::sync::WakerSet;
 use crate::task::{Context, Poll};
 

src/sync/rwlock.rs

@@ -4,9 +4,9 @@ use std::isize;
 use std::ops::{Deref, DerefMut};
 use std::pin::Pin;
 use std::process;
+use std::future::Future;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
-use crate::future::Future;
 use crate::sync::WakerSet;
 use crate::task::{Context, Poll};
 

src/task/block_on.rs

@@ -1,4 +1,5 @@
 use std::cell::Cell;
+use std::future::Future;
 use std::mem::{self, ManuallyDrop};
 use std::sync::Arc;
 use std::task::{RawWaker, RawWakerVTable};
@@ -8,7 +9,6 @@ use crossbeam_utils::sync::Parker;
 use kv_log_macro::trace;
 use log::log_enabled;
 
-use crate::future::Future;
 use crate::task::{Context, Poll, Task, Waker};
 
 /// Spawns a task and blocks the current thread on its result.

src/task/builder.rs

@@ -1,7 +1,7 @@
 use kv_log_macro::trace;
 use log::log_enabled;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::io;
 use crate::task::executor;
 use crate::task::{JoinHandle, Task};

src/task/spawn.rs

@@ -1,4 +1,5 @@
-use crate::future::Future;
+use std::future::Future;
+
 use crate::task::{Builder, JoinHandle};
 
 /// Spawns a task.

src/task/yield_now.rs

@@ -1,6 +1,6 @@
 use std::pin::Pin;
+use std::future::Future;
 
-use crate::future::Future;
 use crate::task::{Context, Poll};
 
 /// Cooperatively gives up a timeslice to the task scheduler.

src/unit/from_stream.rs

@@ -5,12 +5,9 @@ use crate::stream::{FromStream, IntoStream};
 
 impl FromStream<()> for () {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = ()>>(
+    fn from_stream<'a, S: IntoStream<Item = ()> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         Box::pin(stream.into_stream().for_each(|_| ()))
     }
 }

src/vec/from_stream.rs

@@ -3,13 +3,14 @@ use std::pin::Pin;
 use std::rc::Rc;
 use std::sync::Arc;
 
+use crate::prelude::*;
 use crate::stream::{self, FromStream, IntoStream};
 
 impl<T> FromStream<T> for Vec<T> {
     #[inline]
     fn from_stream<'a, S: IntoStream<Item = T>>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>>
     where
         <S as IntoStream>::IntoStream: 'a,
     {
@@ -27,12 +28,9 @@ impl<T> FromStream<T> for Vec<T> {
 
 impl<'b, T: Clone> FromStream<T> for Cow<'b, [T]> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {
@@ -45,12 +43,9 @@ impl<'b, T: Clone> FromStream<T> for Cow<'b, [T]> {
 
 impl<T> FromStream<T> for Box<[T]> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {
@@ -63,12 +58,9 @@ impl<T> FromStream<T> for Box<[T]> {
 
 impl<T> FromStream<T> for Rc<[T]> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {
@@ -81,12 +73,9 @@ impl<T> FromStream<T> for Rc<[T]> {
 
 impl<T> FromStream<T> for Arc<[T]> {
     #[inline]
-    fn from_stream<'a, S: IntoStream<Item = T>>(
+    fn from_stream<'a, S: IntoStream<Item = T> + 'a>(
         stream: S,
-    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
-    where
-        <S as IntoStream>::IntoStream: 'a,
-    {
+    ) -> Pin<Box<dyn Future<Output = Self> + 'a>> {
         let stream = stream.into_stream();
 
         Box::pin(async move {