Make the Entry API of HashMap<K, V> Sync and Send (fixes #45219)

Author: nox

src/libstd/collections/hash/map.rs

@@ -2339,6 +2339,11 @@ pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
     elem: FullBucket<K, V, &'a mut RawTable<K, V>>,
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, K: 'a + Send, V: 'a + Send> Send for OccupiedEntry<'a, K, V> {}
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, K: 'a + Sync, V: 'a + Sync> Sync for OccupiedEntry<'a, K, V> {}
+
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
 impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for OccupiedEntry<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -2360,6 +2365,11 @@ pub struct VacantEntry<'a, K: 'a, V: 'a> {
     elem: VacantEntryState<K, V, &'a mut RawTable<K, V>>,
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, K: 'a + Send, V: 'a + Send> Send for VacantEntry<'a, K, V> {}
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<'a, K: 'a + Sync, V: 'a + Sync> Sync for VacantEntry<'a, K, V> {}
+
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
 impl<'a, K: 'a + Debug, V: 'a> Debug for VacantEntry<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {

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

@@ -53,6 +53,7 @@ fn main() {
     is_sync_send!(BTreeSet::<usize>::new(), union(&BTreeSet::<usize>::new()));
 
     all_sync_send!(HashMap::<usize, usize>::new(), iter, iter_mut, drain, into_iter, keys, values);
+    is_sync_send!(HashMap::<usize, usize>::new(), entry(0));
     all_sync_send!(HashSet::<usize>::new(), iter, drain, into_iter);
     is_sync_send!(HashSet::<usize>::new(), difference(&HashSet::<usize>::new()));
     is_sync_send!(HashSet::<usize>::new(), symmetric_difference(&HashSet::<usize>::new()));