--- /dev/null
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+
+// compile-pass
+
+#![feature(nll)]
+
+fn fibs(n: u32) -> impl Iterator<Item=u128> {
+ (0 .. n)
+ .scan((0, 1), |st, _| {
+ *st = (st.1, st.0 + st.1);
+ Some(*st)
+ })
+ .map(&|(f, _)| f)
+}
+
+fn main() {
+ println!("{:?}", fibs(10).collect::<Vec<_>>());
+}