From 6a085955ea05559f7ad405a42b1b00640f292929 Mon Sep 17 00:00:00 2001
From: Mika Kuoppala <miku@iki.fi>
Date: Wed, 13 Dec 2023 19:13:40 +0200
Subject: [PATCH] src/eat: Check for valid corpsenm before checking is_rider

corpsenm can be -1 so limit checking is_rider with only
>= LOW_PM corpse numbers.
---
 src/eat.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/eat.c b/src/eat.c
index 4668cef36..020292440 100644
--- a/src/eat.c
+++ b/src/eat.c
@@ -57,7 +57,8 @@ static int tin_ok(struct obj *);
    they can be sacrificed regardless of age which implies that they never
    become rotten */
 #define nonrotting_corpse(mnum) \
-    ((mnum) == PM_LIZARD || (mnum) == PM_LICHEN || is_rider(&mons[mnum]) \
+    ((mnum) == PM_LIZARD || (mnum) == PM_LICHEN \
+     || ((mnum) >= LOW_PM && is_rider(&mons[mnum])) \
      || (mnum) == PM_ACID_BLOB)
 
 /* non-rotting non-corpses; unlike lizard corpses, these items will behave