From 918687dcd7c44844c4248280e8b4a9d1a9dac708 Mon Sep 17 00:00:00 2001
From: Rob Pearce <rob@nethack.net>
Date: Wed, 1 Jun 2016 15:03:44 +1000
Subject: [PATCH] Don't make slip on blood checks when climbing stairs.

---
 move.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/move.c b/move.c
index bcde5cc..adbbb68 100644
--- a/move.c
+++ b/move.c
@@ -2666,14 +2666,15 @@ int initiatemove(lifeform_t *lf, cell_t *cell, int onpurpose, int *didmsg) {
 	}
 
 
-	// slipping on something before moving?
+	// slipping on something before moving?  note: we use 'cell' here
+	// rather than lf->cell so that we can skip the check when using stairs.
 	if (!attacking && onpurpose) {
-		if (!isairborne(lf, NULL)) {
+		if (cell && !isairborne(lf, NULL)) {
 			int slip;
 			object_t *slipob;
 
 			if (!lfhasflag(lf, F_CAREFULMOVE)) {
-				slip = getslipperyness(lf->cell, &slipob);
+				slip = getslipperyness(cell, &slipob);
 				if (slip && !skillcheck(lf, SC_SLIP, slip, 0)) {
 					if (!slipon(lf, slipob)) {
 						if (didmsg) *didmsg = B_TRUE;