1 files changed, 57 insertions, 0 deletions
diff --git a/library/core/src/future/pending.rs b/library/core/src/future/pending.rs
new file mode 100644
index 00000000000..74887b68aa0
--- /dev/null
+++ b/library/core/src/future/pending.rs
@@ -0,0 +1,57 @@
+use crate::future::Future;
+use crate::marker;
+use crate::pin::Pin;
+use crate::task::{Context, Poll};
+
+/// Creates a future which never resolves, representing a computation that never
+/// finishes.
+///
+/// This `struct` is created by the [`pending`] function. See its
+/// documentation for more.
+///
+/// [`pending`]: fn.pending.html
+#[unstable(feature = "future_readiness_fns", issue = "70921")]
+#[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
+pub struct Pending<T> {
+    _data: marker::PhantomData<T>,
+}
+
+/// Creates a future which never resolves, representing a computation that never
+/// finishes.
+///
+/// # Examples
+///
+/// ```no_run
+/// #![feature(future_readiness_fns)]
+/// use core::future;
+///
+/// # async fn run() {
+/// let future = future::pending();
+/// let () = future.await;
+/// unreachable!();
+/// # }
+/// ```
+#[unstable(feature = "future_readiness_fns", issue = "70921")]
+pub fn pending<T>() -> Pending<T> {
+    Pending { _data: marker::PhantomData }
+}
+
+#[unstable(feature = "future_readiness_fns", issue = "70921")]
+impl<T> Future for Pending<T> {
+    type Output = T;
+
+    fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<T> {
+        Poll::Pending
+    }
+}
+
+#[unstable(feature = "future_readiness_fns", issue = "70921")]
+impl<T> Unpin for Pending<T> {}
+
+#[unstable(feature = "future_readiness_fns", issue = "70921")]
+impl<T> Clone for Pending<T> {
+    fn clone(&self) -> Self {
+        pending()
+    }
+}