Add Send/Sync traits on Iter struct in hash/table

src/libstd/collections/hash/set.rs

@@ -11,7 +11,7 @@
 use borrow::Borrow;
 use clone::Clone;
 use cmp::{Eq, PartialEq};
-use core::marker::Sized;
+use core::marker::{Sized, Send, Sync};
 use default::Default;
 use fmt::Debug;
 use fmt;
@@ -764,18 +764,27 @@ pub struct Iter<'a, K: 'a> {
     iter: Keys<'a, K, ()>
 }
 
+unsafe impl<'a, K: Send> Send for Iter<'a, K> {}
+unsafe impl<'a, K: Sync> Sync for Iter<'a, K> {}
+
 /// HashSet move iterator
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct IntoIter<K> {
     iter: Map<map::IntoIter<K, ()>, fn((K, ())) -> K>
 }
 
+unsafe impl<K: Send> Send for IntoIter<K> {}
+unsafe impl<K: Sync> Sync for IntoIter<K> {}
+
 /// HashSet drain iterator
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Drain<'a, K: 'a> {
     iter: Map<map::Drain<'a, K, ()>, fn((K, ())) -> K>,
 }
 
+unsafe impl<'a, K: Send> Send for Drain<'a, K> {}
+unsafe impl<'a, K: Sync> Sync for Drain<'a, K> {}
+
 /// Intersection iterator
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Intersection<'a, T: 'a, S: 'a> {
@@ -785,6 +794,9 @@ pub struct Intersection<'a, T: 'a, S: 'a> {
     other: &'a HashSet<T, S>,
 }
 
+unsafe impl<'a, K: Send, S: Send> Send for Intersection<'a, K, S> {}
+unsafe impl<'a, K: Sync, S: Send> Sync for Intersection<'a, K, S> {}
+
 /// Difference iterator
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Difference<'a, T: 'a, S: 'a> {
@@ -794,18 +806,27 @@ pub struct Difference<'a, T: 'a, S: 'a> {
     other: &'a HashSet<T, S>,
 }
 
+unsafe impl<'a, K: Send, S: Send> Send for Difference<'a, K, S> {}
+unsafe impl<'a, K: Sync, S: Send> Sync for Difference<'a, K, S> {}
+
 /// Symmetric difference iterator.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct SymmetricDifference<'a, T: 'a, S: 'a> {
     iter: Chain<Difference<'a, T, S>, Difference<'a, T, S>>
 }
 
+unsafe impl<'a, K: Send, S: Send> Send for SymmetricDifference<'a, K, S> {}
+unsafe impl<'a, K: Sync, S: Send> Sync for SymmetricDifference<'a, K, S> {}
+
 /// Set union iterator.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Union<'a, T: 'a, S: 'a> {
     iter: Chain<Iter<'a, T>, Difference<'a, T, S>>
 }
 
+unsafe impl<'a, K: Send, S: Send> Send for Union<'a, K, S> {}
+unsafe impl<'a, K: Sync, S: Send> Sync for Union<'a, K, S> {}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T, S> IntoIterator for &'a HashSet<T, S>
     where T: Eq + Hash, S: HashState

src/libstd/collections/hash/table.rs

@@ -741,6 +741,9 @@ struct RawBuckets<'a, K, V> {
     marker: marker::PhantomData<&'a ()>,
 }
 
+unsafe impl<'a, K: Send, V: Send> Send for RawBuckets<'a, K, V> {}
+unsafe impl<'a, K: Sync, V: Sync> Sync for RawBuckets<'a, K, V> {}
+
 // FIXME(#19839) Remove in favor of `#[derive(Clone)]`
 impl<'a, K, V> Clone for RawBuckets<'a, K, V> {
     fn clone(&self) -> RawBuckets<'a, K, V> {

src/test/run-pass/sync-send-iterators-in-libcollections.rs

@@ -25,6 +25,7 @@ use collections::String;
 use collections::Vec;
 use collections::VecDeque;
 use collections::VecMap;
+use std::collections::HashMap;
 
 use collections::Bound::Included;
 use collections::enum_set::CLike;
@@ -77,6 +78,8 @@ fn main() {
     is_sync_send!(BTreeSet::<usize>::new(), intersection(&BTreeSet::<usize>::new()));
     is_sync_send!(BTreeSet::<usize>::new(), union(&BTreeSet::<usize>::new()));
 
+    all_sync_send!(HashMap::<usize, usize>::new(), keys, values, iter, iter_mut);
+
     all_sync_send!(LinkedList::<usize>::new(), iter, iter_mut, into_iter);
 
     #[derive(Copy, Clone)]