Question in `next` of `impl Iterator for MoveGen`

[miguel-ambrona]

I'm puzzled by this first case: https://github.com/jordanbray/chess/blob/main/src/movegen/movegen.rs#L302-L306

    fn next(&mut self) -> Option<ChessMove> {
        if self.index >= self.moves.len()
            || self.moves[self.index].bitboard & self.iterator_mask == EMPTY
        {
            // are we done?
            None

Shouldn't we increase self.index before returning None?

[miguel-ambrona]

Ok, I guess this works without increasing self.index because of two properties:

• All self.moves have a non-empty .bitboard (at least initially).

• Function set_iterator_mask does some magic: it sorts the moves in such a way that the ones with remaining destinies always go first.

  I would then rephrase the above comment: // are we done? -> // we are done, or just remove it. It confused me a little.