Minor tweaks

futures-util/src/stream/try_stream/mod.rs

@@ -687,7 +687,6 @@ pub trait TryStreamExt: TryStream {
         limit: impl Into<Option<usize>>,
     ) -> TryFlattenUnordered<Self, I, E>
     where
-        Self: TryStream,
         Self::Ok: futures_core::Stream<Item = Result<I, E>>,
         E: From<Self::Error>,
         Self: Sized,

futures-util/src/stream/try_stream/try_flatten_unordered.rs

@@ -28,9 +28,10 @@ delegate_all!(
 );
 
 pin_project! {
-    /// Flattens successful streams from the given stream, bubbling up the errors.
+    /// Emits either successful streams or single-item streams containing the underlying errors.
     /// This's a wrapper for `FlattenUnordered` to reuse its logic over `TryStream`.
     #[derive(Debug)]
+    #[must_use = "streams do nothing unless polled"]
     pub struct TryFlattenSuccessful<St, I, E>
         where
             St: TryStream,
@@ -66,13 +67,13 @@ where
     }
 }
 
-/// Emits one item immediately, then stream will be terminated.
+/// Emits single item immediately, then stream will be terminated.
 #[derive(Debug, Clone)]
-pub struct One<T>(Option<T>);
+pub struct Single<T>(Option<T>);
 
-impl<T> Unpin for One<T> {}
+impl<T> Unpin for Single<T> {}
 
-impl<T> Stream for One<T> {
+impl<T> Stream for Single<T> {
     type Item = T;
 
     fn poll_next(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Option<Self::Item>> {
@@ -84,7 +85,7 @@ impl<T> Stream for One<T> {
     }
 }
 
-type OneResult<St> = One<
+type SingleResult<St> = Single<
     Result<<<St as TryStream>::Ok as TryStream>::Ok, <<St as TryStream>::Ok as TryStream>::Error>,
 >;
 
@@ -96,19 +97,19 @@ where
 {
     // Item is either an inner stream or a stream containing a single error.
     // This will allow using `Either`'s `Stream` implementation as both branches are actually streams of `Result`'s.
-    type Item = Either<St::Ok, OneResult<St>>;
+    type Item = Either<St::Ok, SingleResult<St>>;
 
     fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
         let item = ready!(self.project().stream.try_poll_next(cx));
 
         let out = item.map(|res| match res {
-            // Emit inner stream as is
+            // Emit successful inner stream as is
             Ok(stream) => Either::Left(stream),
-            // Wrap an error into stream wrapper containing one item
+            // Wrap an error into a stream containing a single item
             err @ Err(_) => {
                 let res = err.map(|_: St::Ok| unreachable!()).map_err(Into::into);
 
-                Either::Right(One(Some(res)))
+                Either::Right(Single(Some(res)))
             }
         });