occ ^= (b & (~b + 1));
attackers |= (attacks_bb<ROOK>(to, occ) & pieces(ROOK, QUEEN))
| (attacks_bb<BISHOP>(to, occ) & pieces(BISHOP, QUEEN));
occ ^= (b & (~b + 1));
attackers |= (attacks_bb<ROOK>(to, occ) & pieces(ROOK, QUEEN))
| (attacks_bb<BISHOP>(to, occ) & pieces(BISHOP, QUEEN));