// En passant move? We assume that a pawn move is an en passant move
// if the destination square is epSquare.
if (to == pos.ep_square() && piece == piece_of_color_and_type(us, PAWN))
// En passant move? We assume that a pawn move is an en passant move
// if the destination square is epSquare.
if (to == pos.ep_square() && piece == piece_of_color_and_type(us, PAWN))