Bug in MoveGen when setting a mask

[s-arash]

Looks like MoveGen misses moves when a mask is set. Here is my test code:

let board = Board::from_str("r1bqkb1r/pp3ppp/5n2/2ppn1N1/4pP2/1BN1P3/PPPP2PP/R1BQ1RK1 w kq - 0 9").unwrap();

let mut capture_moves = MoveGen::new_legal(&board);
let targets = *board.color_combined(!board.side_to_move());
capture_moves.set_iterator_mask(targets);

for m in capture_moves{
    print!("{}, ", m);
}

It only prints this move:

f4e5,

[jordanbray]

This is resolved in 3.1.1.