Make vec::Drain and binary_heap::Drain covariant

2 files changed, 12 insertions, 0 deletions

diff --git a/src/libcollectionstest/binary_heap.rs b/src/libcollectionstest/binary_heap.rs
index be933abe41f..39efc9fc22c 100644
--- a/src/libcollectionstest/binary_heap.rs
+++ b/src/libcollectionstest/binary_heap.rs
@@ -9,6 +9,7 @@
 // except according to those terms.
 
 use std::collections::BinaryHeap;
+use std::collections::binary_heap::Drain;
 
 #[test]
 fn test_iterator() {
@@ -292,3 +293,8 @@ fn test_extend_specialization() {
 
     assert_eq!(a.into_sorted_vec(), [-20, -10, 1, 2, 3, 3, 5, 43]);
 }
+
+#[allow(dead_code)]
+fn assert_covariance() {
+    fn drain<'new>(d: Drain<&'static str>) -> Drain<&'new str> { d }
+}
diff --git a/src/libcollectionstest/vec.rs b/src/libcollectionstest/vec.rs
index cb99659cc0e..01656b44a84 100644
--- a/src/libcollectionstest/vec.rs
+++ b/src/libcollectionstest/vec.rs
@@ -11,6 +11,7 @@
 use std::borrow::Cow;
 use std::iter::{FromIterator, repeat};
 use std::mem::size_of;
+use std::vec::Drain;
 
 use test::Bencher;
 
@@ -510,6 +511,11 @@ fn test_cow_from() {
     }
 }
 
+#[allow(dead_code)]
+fn assert_covariance() {
+    fn drain<'new>(d: Drain<&'static str>) -> Drain<&'new str> { d }
+}
+
 #[bench]
 fn bench_new(b: &mut Bencher) {
     b.iter(|| {