original.name="Reference_Valid_36"
======
>>> main.whiley
type Node is &{ List next, int data }
type List is null | Node
method next(Node r):
skip
public export method test():
List p = new Node{next: null, data: 0}
List q = new Node{next: null, data: 1}
assert q->data == 1
next(p)
assert p->next != q
assert q->data == 1
---