1 files changed, 19 insertions, 10 deletions
diff --git a/src/future/select.rs b/src/future/select.rs
index bc24779..043ed17 100644
--- a/src/future/select.rs
+++ b/src/future/select.rs
@@ -1,3 +1,4 @@
+use super::assert_future;
 use core::pin::Pin;
 use futures_core::future::{Future, FusedFuture};
 use futures_core::task::{Context, Poll};
@@ -31,25 +32,33 @@ impl<A: Unpin, B: Unpin> Unpin for Select<A, B> {}
 ///
 /// ```
 /// # futures::executor::block_on(async {
-/// use futures::future::{self, Either};
-/// use futures::pin_mut;
-///
-/// // These two futures have different types even though their outputs have the same type
-/// let future1 = async { 1 };
-/// let future2 = async { 2 };
+/// use futures::{
+///     pin_mut,
+///     future::Either,
+///     future::self,
+/// };
+/// 
+/// // These two futures have different types even though their outputs have the same type.
+/// let future1 = async {
+///     future::pending::<()>().await; // will never finish
+///     1
+/// };
+/// let future2 = async { 
+///     future::ready(2).await
+/// };
 ///
 /// // 'select' requires Future + Unpin bounds
 /// pin_mut!(future1);
 /// pin_mut!(future2);
 ///
 /// let value = match future::select(future1, future2).await {
-///     Either::Left((value1, _)) => value1, // `value1` is resolved from `future1`
-///                                          // `_` represents `future2`
+///     Either::Left((value1, _)) => value1,  // `value1` is resolved from `future1`
+///                                           // `_` represents `future2`
 ///     Either::Right((value2, _)) => value2, // `value2` is resolved from `future2`
 ///                                           // `_` represents `future1`
 /// };
 ///
-/// assert!(value == 1 || value == 2);
+/// assert!(value == 2);
 /// # });
 /// ```
 ///
@@ -75,7 +84,7 @@ impl<A: Unpin, B: Unpin> Unpin for Select<A, B> {}
 pub fn select<A, B>(future1: A, future2: B) -> Select<A, B>
     where A: Future + Unpin, B: Future + Unpin
 {
-    Select { inner: Some((future1, future2)) }
+    assert_future::<Either<(A::Output, B), (B::Output, A)>, _>(Select { inner: Some((future1, future2)) })
 }
 
 impl<A, B> Future for Select<A, B>