Fix doctest of `ExactSizeIterator::is_empty`

diff --git a/src/libcore/iter/traits.rs b/src/libcore/iter/traits.rs
index b7ee9ba55f5910a62d0cc8e8b9447ea1ca8c7a93..b1af30559328c6f3f6289cb0bc13313e179bf01c 100644 (file)
--- a/src/libcore/iter/traits.rs
+++ b/src/libcore/iter/traits.rs
@@ -530,7 +530,9 @@ fn len(&self) -> usize {
     /// Basic usage:
     ///
     /// ```
-    /// let mut one_element = [0].iter();
+    /// #![feature(exact_size_is_empty)]
+    ///
+    /// let mut one_element = 0..1;
     /// assert!(!one_element.is_empty());
     ///
     /// assert_eq!(one_element.next(), Some(0));