Method effect

crawl-ref/source/potion.cc:719–725

    }

    bool effect(bool=true, int pow = 40, bool is_potion = true) const override
    {
        mprf(MSGCH_DURATION, "You feel protected.");
        const int add = _scale_pot_duration(35 + random2(pow), is_potion);;
        you.increase_duration(DUR_RESISTANCE, add);
        return true;
    }
};

class PotionLignify : public PotionEffect