tree: bug: tree-delete-specific-node doesn't use key fun

* tree.c (tr_delete_specific): We cant' juse use key(node)
as the search key; we must apply the tree's key function
to the node key field to retrieve the correct search key.

* tests/010/tree.tl: New test case which fails without
this bugfix: a node which is the left subtree of the root
node doesn't get deleted since the search is led astray
by the wrong key object.

2 files changed, 10 insertions, 2 deletions

diff --git a/tests/010/tree.tl b/tests/010/tree.tl
index 56d04fa9..9d00fda6 100644
--- a/tests/010/tree.tl
+++ b/tests/010/tree.tl
@@ -166,7 +166,7 @@
   (tree-delete tr 18) 18
   (tree-delete tr 19) 19)
 
-(set *tree-fun-whitelist* [list* '= '< *tree-fun-whitelist*])
+(set *tree-fun-whitelist* [list* '= '< 'to *tree-fun-whitelist*])
 
 (let ((tr [tree '(1 2 3) identity < =]))
   (mtest
@@ -256,3 +256,9 @@
     (tree-del-min tr) 10
     (tree-count tr) 0
     (tree-del-min tr) nil))
+
+(let* ((tr [tree '(#R(1 10) #R(11 20) #R(21 30)) to])
+       (node (tree-lookup-node tr 10)))
+  (test node #N(#R(1 10) nil nil))
+  (tree-delete-specific-node tr node)
+  (test tr #T((to) #R(11 20) #R(21 30))))
diff --git a/tree.c b/tree.c
index 3a5f52db..01844931 100644
--- a/tree.c
+++ b/tree.c
@@ -589,8 +589,10 @@ static val tr_delete(val tree, struct tree *tr, val key)
 static val tr_delete_specific(val tree, struct tree *tr, val thisnode)
 {
   if (tr->root) {
+    val nkey = key(thisnode);
+    val key = if3(tr->key_fn, funcall1(tr->key_fn, nkey), nkey);
     val node = tr_do_delete_specific(tree, tr, tr->root,
-                                     nil, key(thisnode), thisnode);
+                                     nil, key, thisnode);
     if (node) {
       if (2 * --tr->size < tr->max_size) {
         tr_rebuild(tree, tr, tr->root, nil, tr->size);