Fix check test with multi-leg moves

The check test after a multi-leg move was still using the same kill
square in the opponent's reply, making it blind to King captures in
a second leg. So far we got away with that because the Shogi multi-leg
pieces also can reach all their potential victims in a single step,
but with engine-defined multi-leg moves there is no guarantee this
will always be the case.

diff --git a/moves.c b/moves.c
index 54f46c8..aca97b5 100644 (file)
--- a/moves.c
+++ b/moves.c
@@ -1610,6 +1610,7 @@ CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant
     CheckTestClosure cl;
     ChessSquare king = flags & F_WHITE_ON_MOVE ? WhiteKing : BlackKing;
     ChessSquare captured = EmptySquare, ep=0, trampled=0;
+    int saveKill = killX;
     /*  Suppress warnings on uninitialized variables    */
 
     if(gameInfo.variant == VariantXiangqi)
@@ -1632,7 +1633,7 @@ CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant
            board[rf][ft] = EmptySquare;
        } else {
            captured = board[rt][ft];
-           if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; }
+           if(killX >= 0) { trampled = board[killY][killX]; board[killY][killX] = EmptySquare; killX = -1; }
        }
        if(rf == DROP_RANK) board[rt][ft] = ff; else { // [HGM] drop
            board[rt][ft] = board[rf][ff];
@@ -1680,7 +1681,7 @@ CheckTest (Board board, int flags, int rf, int ff, int rt, int ft, int enPassant
            board[rf][ft] = captured;
            board[rt][ft] = EmptySquare;
        } else {
-           if(killX >= 0) board[killY][killX] = trampled;
+           if(saveKill >= 0) board[killY][killX] = trampled, killX = saveKill;
            board[rt][ft] = captured;
        }
        board[EP_STATUS] = ep;