2 files changed, 25 insertions, 2 deletions
diff --git a/libcore/iter/iterator.rs b/libcore/iter/iterator.rs
index 2033ae5..71ca5cc 100644
--- a/libcore/iter/iterator.rs
+++ b/libcore/iter/iterator.rs
@@ -172,6 +172,7 @@ pub trait Iterator {
     /// assert_eq!(a.iter().count(), 5);
     /// ```
     #[inline]
+    #[rustc_inherit_overflow_checks]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn count(self) -> usize where Self: Sized {
         // Might overflow.
@@ -214,7 +215,7 @@ pub trait Iterator {
     /// Like most indexing operations, the count starts from zero, so `nth(0)`
     /// returns the first value, `nth(1)` the second, and so on.
     ///
-    /// `nth()` will return `None` if `n` is larger than the length of the
+    /// `nth()` will return `None` if `n` is greater than or equal to the length of the
     /// iterator.
     ///
     /// # Examples
@@ -237,7 +238,7 @@ pub trait Iterator {
     /// assert_eq!(iter.nth(1), None);
     /// ```
     ///
-    /// Returning `None` if there are less than `n` elements:
+    /// Returning `None` if there are less than `n + 1` elements:
     ///
     /// ```
     /// let a = [1, 2, 3];
diff --git a/libcore/iter/mod.rs b/libcore/iter/mod.rs
index abc199c..ae1e311 100644
--- a/libcore/iter/mod.rs
+++ b/libcore/iter/mod.rs
@@ -510,6 +510,7 @@ impl<A, B> Iterator for Chain<A, B> where
     }
 
     #[inline]
+    #[rustc_inherit_overflow_checks]
     fn count(self) -> usize {
         match self.state {
             ChainState::Both => self.a.count() + self.b.count(),
@@ -542,6 +543,23 @@ impl<A, B> Iterator for Chain<A, B> where
     }
 
     #[inline]
+    fn find<P>(&mut self, mut predicate: P) -> Option<Self::Item> where
+        P: FnMut(&Self::Item) -> bool,
+    {
+        match self.state {
+            ChainState::Both => match self.a.find(&mut predicate) {
+                None => {
+                    self.state = ChainState::Back;
+                    self.b.find(predicate)
+                }
+                v => v
+            },
+            ChainState::Front => self.a.find(predicate),
+            ChainState::Back => self.b.find(predicate),
+        }
+    }
+
+    #[inline]
     fn last(self) -> Option<A::Item> {
         match self.state {
             ChainState::Both => {
@@ -915,6 +933,7 @@ impl<I> Iterator for Enumerate<I> where I: Iterator {
     ///
     /// Might panic if the index of the element overflows a `usize`.
     #[inline]
+    #[rustc_inherit_overflow_checks]
     fn next(&mut self) -> Option<(usize, <I as Iterator>::Item)> {
         self.iter.next().map(|a| {
             let ret = (self.count, a);
@@ -930,6 +949,7 @@ impl<I> Iterator for Enumerate<I> where I: Iterator {
     }
 
     #[inline]
+    #[rustc_inherit_overflow_checks]
     fn nth(&mut self, n: usize) -> Option<(usize, I::Item)> {
         self.iter.nth(n).map(|a| {
             let i = self.count + n;
@@ -991,6 +1011,7 @@ impl<I: Iterator> Iterator for Peekable<I> {
     }
 
     #[inline]
+    #[rustc_inherit_overflow_checks]
     fn count(self) -> usize {
         (if self.peeked.is_some() { 1 } else { 0 }) + self.iter.count()
     }
@@ -1108,6 +1129,7 @@ impl<I: Iterator> Peekable<I> {
     /// ```
     #[unstable(feature = "peekable_is_empty", issue = "32111")]
     #[inline]
+    #[rustc_deprecated(since = "1.10.0", reason = "replaced by .peek().is_none()")]
     pub fn is_empty(&mut self) -> bool {
         self.peek().is_none()
     }