1 files changed, 38 insertions, 0 deletions
diff --git a/library/core/src/async_iter/from_iter.rs b/library/core/src/async_iter/from_iter.rs
new file mode 100644
index 000000000..3180187af
--- /dev/null
+++ b/library/core/src/async_iter/from_iter.rs
@@ -0,0 +1,38 @@
+use crate::pin::Pin;
+
+use crate::async_iter::AsyncIterator;
+use crate::task::{Context, Poll};
+
+/// An async iterator that was created from iterator.
+///
+/// This async iterator is created by the [`from_iter`] function.
+/// See it documentation for more.
+///
+/// [`from_iter`]: fn.from_iter.html
+#[unstable(feature = "async_iter_from_iter", issue = "81798")]
+#[derive(Clone, Debug)]
+pub struct FromIter<I> {
+    iter: I,
+}
+
+#[unstable(feature = "async_iter_from_iter", issue = "81798")]
+impl<I> Unpin for FromIter<I> {}
+
+/// Converts an iterator into an async iterator.
+#[unstable(feature = "async_iter_from_iter", issue = "81798")]
+pub fn from_iter<I: IntoIterator>(iter: I) -> FromIter<I::IntoIter> {
+    FromIter { iter: iter.into_iter() }
+}
+
+#[unstable(feature = "async_iter_from_iter", issue = "81798")]
+impl<I: Iterator> AsyncIterator for FromIter<I> {
+    type Item = I::Item;
+
+    fn poll_next(mut self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        Poll::Ready(self.iter.next())
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}