Method effect

crawl-ref/source/potion.cc:256–260

    }

    bool effect(bool=true, int=0, bool is_potion = true) const override
    {
        const int dur = _scale_pot_duration(random_range(26, 40), is_potion);
        return haste_player(dur);
    }

    bool quaff(bool was_known) const override
    {