const enum Piece P = make_piece(Us, PAWN);
Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
if (pos.piece_on(s + d) == P)
const enum Piece P = make_piece(Us, PAWN);
Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
if (pos.piece_on(s + d) == P)