Add missing stability attributes on struct fields.

Unstable is the conservative choice.

cc #22950.

diff --git a/src/libcore/iter.rs b/src/libcore/iter.rs
index 88a729a3db09e92682022b71406d35cd6f483930..57a6613debd583d4d3cbaf550548f84f02809c55 100644 (file)
--- a/src/libcore/iter.rs
+++ b/src/libcore/iter.rs
@@ -2061,6 +2061,7 @@ pub struct Scan<I, St, F> {
     f: F,
 
     /// The current internal state to be passed to the closure next.
+    #[unstable(feature = "core")]
     pub state: St,
 }
 
@@ -2338,6 +2339,7 @@ fn idx(&mut self, index: usize) -> Option<I::Item> {
 pub struct Unfold<St, F> {
     f: F,
     /// Internal state that will be passed to the closure on the next iteration
+    #[unstable(feature = "core")]
     pub state: St,
 }