---

yaml
---
r: 212650
b: refs/heads/beta
c: 1c0b2f4
h: refs/heads/master
v: v3

Author: Gankra

[refs]

@@ -29,7 +29,7 @@ refs/tags/0.12.0: f0c419429ef30723ceaf6b42f9b5a2aeb5d2e2d1
 refs/heads/automation-fail: 1bf06495443584539b958873e04cc2f864ab10e4
 refs/heads/batch: b7fd822592a4fb577552d93010c4a4e14f314346
 refs/heads/building: 126db549b038c84269a1e4fe46f051b2c15d6970
-refs/heads/beta: 2cc6e8fb538d5a629501e2a55e439cf4c8f98b2c
+refs/heads/beta: 1c0b2f42c86a12dd49b164ee0df97208a9cee20e
 refs/heads/windistfix: 7608dbad651f02e837ed05eef3d74a6662a6e928
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
 refs/heads/tmp: a224db5e630715d9f46938fe07b58eb644e3c27d

branches/beta/src/libcollections/linked_list.rs

@@ -616,7 +616,13 @@ impl<T> LinkedList<T> {
             length: len - at
         };
 
+        // Swap split_node.next with list_head (which is None), nulling out split_node.next,
+        // as it is the new tail.
         mem::swap(&mut split_node.resolve().unwrap().next, &mut splitted_list.list_head);
+        // Null out list_head.prev. Note this `unwrap` won't fail because if at == len
+        // we already branched out at the top of the fn to return the empty list.
+        splitted_list.list_head.as_mut().unwrap().prev = Rawlink::none();
+        // Fix the tail ptr
         self.list_tail = split_node;
         self.length = at;
 
@@ -1082,6 +1088,26 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_26021() {
+        use std::iter::ExactSizeIterator;
+        // There was a bug in split_off that failed to null out the RHS's head's prev ptr.
+        // This caused the RHS's dtor to walk up into the LHS at drop and delete all of
+        // its nodes.
+        //
+        // https://github.com/rust-lang/rust/issues/26021
+        let mut v1 = LinkedList::new();
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        v1.push_front(1u8);
+        let _ = v1.split_off(3); // Dropping this now should not cause laundry consumption
+        assert_eq!(v1.len(), 3);
+
+        assert_eq!(v1.iter().len(), 3);
+        assert_eq!(v1.iter().collect::<Vec<_>>().len(), 3);
+    }
+
     #[cfg(test)]
     fn fuzz_test(sz: i32) {
         let mut m: LinkedList<_> = LinkedList::new();