From b9942fbfad217952a1135345d47860be3ebee6a6 Mon Sep 17 00:00:00 2001
From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Sun, 18 Feb 2018 11:20:09 +0100
Subject: [PATCH] Fix board corruption on null move

Faking a piece other than the one actually there on the to-square
of a null move interfered with the kludge for testing castling legality,
by actually putting back that piece there. Better solutions should be
possible here.
---
 dropper.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/dropper.c b/dropper.c
index 8261873..742f8ec 100644
--- a/dropper.c
+++ b/dropper.c
@@ -1223,7 +1223,7 @@ Search (int stm, int alpha, int beta, StackFrame *ff, int depth, int reduction,
 	f.mutation = -2; // kludge to suppress testing for discovered check
 	f.newEval = f.pstEval;
 	f.newKey = f.hashKey;
-	f.epSqr = -1; f.fromSqr = f.toSqr = f.captSqr = 1; f.toPiece = stm; // fake Pawn to suppress early move gen in reply node
+	f.epSqr = -1; f.fromSqr = f.toSqr = f.captSqr = 1; f.toPiece = board[1];
 	deprec[ply] = maxDepth << 16 | depth << 8; path[ply++] = 0;
 	score = -Search(stm, -beta, 1-beta, &f, nullDepth, 0, nullDepth);
 	ply--;
-- 
1.7.0.4