Indicate tracking issue for `exact_size_is_empty` unstability.

diff --git a/src/libcore/iter/traits.rs b/src/libcore/iter/traits.rs
index 292d72dd362ad5c203497361cd9cda2febfaebc7..4cbabe3f5edafc1036216b05470c7cd7d5478169 100644 (file)
--- a/src/libcore/iter/traits.rs
+++ b/src/libcore/iter/traits.rs
@@ -548,7 +548,7 @@ fn len(&self) -> usize {
     /// assert_eq!(one_element.next(), None);
     /// ```
     #[inline]
-    #[unstable(feature = "exact_size_is_empty", issue = "0")]
+    #[unstable(feature = "exact_size_is_empty", issue = "35428")]
     fn is_empty(&self) -> bool {
         self.len() == 0
     }