const dungeon_feature_type mgrid = grd(monster->pos());

    // Don't move onto dangerous terrain.
    if (is_grid_dangerous(grd(monster->pos())))
    {
        canned_msg(MSG_UNTHINKING_ACT);
        return (false);
    }

    const bool mon_dest_okay = _habitat_okay( monster, grd(you.pos()) );
    const bool you_dest_okay =
        !is_grid_dangerous(mgrid)
        || yesno("Do you really want to step there?", false, 'n');

    // First try: move monster onto your position.
    bool swap = _habitat_okay( monster, grd(loc) );

    if (!you_dest_okay)
        return (false);
    bool swap = mon_dest_okay;