Implement Clone for std::vec::IntoIter

src/libcollections/vec.rs

@@ -59,9 +59,10 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use alloc::raw_vec::RawVec;
 use alloc::boxed::Box;
 use alloc::heap::EMPTY;
+use alloc::raw_vec::RawVec;
+use borrow::ToOwned;
 use core::cmp::Ordering;
 use core::fmt;
 use core::hash::{self, Hash};
@@ -1633,6 +1634,15 @@ impl<T> DoubleEndedIterator for IntoIter<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> ExactSizeIterator for IntoIter<T> {}
 
+#[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
+impl<T: Clone> Clone for IntoIter<T> {
+    fn clone(&self) -> IntoIter<T> {
+        unsafe {
+            slice::from_raw_parts(self.ptr, self.len()).to_owned().into_iter()
+        }
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> Drop for IntoIter<T> {
     #[unsafe_destructor_blind_to_params]

src/libcollectionstest/vec.rs

@@ -467,6 +467,24 @@ fn test_into_iter_count() {
     assert_eq!(vec![1, 2, 3].into_iter().count(), 3);
 }
 
+#[test]
+fn test_into_iter_clone() {
+    fn iter_equal<I: Iterator<Item=i32>>(it: I, slice: &[i32]) {
+        let v: Vec<i32> = it.collect();
+        assert_eq!(&v[..], slice);
+    }
+    let mut it = vec![1, 2, 3].into_iter();
+    iter_equal(it.clone(), &[1, 2, 3]);
+    assert_eq!(it.next(), Some(1));
+    let mut it = it.rev();
+    iter_equal(it.clone(), &[3, 2]);
+    assert_eq!(it.next(), Some(3));
+    iter_equal(it.clone(), &[2]);
+    assert_eq!(it.next(), Some(2));
+    iter_equal(it.clone(), &[]);
+    assert_eq!(it.next(), None);
+}
+
 #[test]
 fn test_cow_from() {
     let borrowed: &[_] = &["borrowed", "(slice)"];