assert(pos.piece_on(to - pawn_push(us)) == piece_of_color_and_type(them, PAWN));
// The move is pseudo-legal, check if it is also legal
assert(pos.piece_on(to - pawn_push(us)) == piece_of_color_and_type(them, PAWN));
// The move is pseudo-legal, check if it is also legal