tree: insert must clear left/right links.

* tree.c (tree_insert_node): A node being inserted might not
have null left and right links; we must clear them.

1 files changed, 3 insertions, 0 deletions

diff --git a/tree.c b/tree.c
index 018f52c3..4f81a7a1 100644
--- a/tree.c
+++ b/tree.c
@@ -388,6 +388,9 @@ static val tree_insert_node(val tree, val node)
 
   type_check(self, node, TNOD);
 
+  node->tn.left = nil;
+  node->tn.right = nil;
+
   if (tr->root == nil) {
     tr->size = 1;
     tr->max_size = 1;