Support try_collect in no_std environment

Author: taiki-e

futures-util/src/try_stream/mod.rs

@@ -32,6 +32,9 @@ pub use self::try_for_each::TryForEach;
 mod try_filter_map;
 pub use self::try_filter_map::TryFilterMap;
 
+mod try_collect;
+pub use self::try_collect::TryCollect;
+
 mod try_concat;
 pub use self::try_concat::TryConcat;
 
@@ -46,11 +49,6 @@ mod try_buffer_unordered;
 #[cfg(feature = "std")]
 pub use self::try_buffer_unordered::TryBufferUnordered;
 
-#[cfg(feature = "std")]
-mod try_collect;
-#[cfg(feature = "std")]
-pub use self::try_collect::TryCollect;
-
 #[cfg(feature = "std")]
 mod try_for_each_concurrent;
 #[cfg(feature = "std")]
@@ -334,9 +332,6 @@ pub trait TryStreamExt: TryStream {
     ///
     /// The returned future will be resolved when the stream terminates.
     ///
-    /// This method is only available when the `std` feature of this
-    /// library is activated, and it is activated by default.
-    ///
     /// # Examples
     ///
     /// ```
@@ -360,7 +355,6 @@ pub trait TryStreamExt: TryStream {
     /// assert_eq!(output, Err(6));
     /// # })
     /// ```
-    #[cfg(feature = "std")]
     fn try_collect<C: Default + Extend<Self::Ok>>(self) -> TryCollect<Self, C>
         where Self: Sized
     {

futures-util/src/try_stream/try_collect.rs

@@ -1,10 +1,9 @@
+use core::mem;
+use core::pin::Pin;
 use futures_core::future::{FusedFuture, Future};
 use futures_core::stream::{FusedStream, TryStream};
 use futures_core::task::{Waker, Poll};
 use pin_utils::{unsafe_pinned, unsafe_unpinned};
-use std::mem;
-use std::pin::Pin;
-use std::prelude::v1::*;
 
 /// A future which attempts to collect all of the values of a stream.
 ///

futures/src/lib.rs

@@ -347,15 +347,15 @@ pub mod stream {
     pub use futures_util::try_stream::{
         TryStreamExt,
         TryNext, TryForEach, ErrInto,
-        TryFold, TrySkipWhile,
+        TryCollect, TryFold, TrySkipWhile,
         IntoStream,
         // ToDo: AndThen, ErrInto, InspectErr, MapErr, OrElse
     };
 
     #[cfg(feature = "std")]
     pub use futures_util::try_stream::{
         // For TryStreamExt:
-        TryCollect, TryBufferUnordered,
+        TryBufferUnordered,
         // ToDo: AndThen, InspectErr, MapErr, OrElse
     };
 }