From aec28f3ad3b4605951b544d2813c7de3a17ecc35 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Wed, 6 Aug 2025 08:12:08 +0200
Subject: [PATCH] splay: add another assert for detected usage problem

Closes #18199
---
 lib/splay.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/splay.c b/lib/splay.c
index 609b799bfd..3ca8678b2b 100644
--- a/lib/splay.c
+++ b/lib/splay.c
@@ -223,6 +223,7 @@ int Curl_splayremove(struct Curl_tree *t,
   if(compare(SPLAY_SUBNODE, removenode->key) == 0) {
     /* It is a subnode within a 'same' linked list and thus we can unlink it
        easily. */
+    DEBUGASSERT(removenode->samen != removenode);
     if(removenode->samen == removenode)
       /* A non-subnode should never be set to SPLAY_SUBNODE */
       return 3;