Method lowerToPossible

lib/vf_analyzers.cpp:1002–1009

    }

    bool lowerToPossible() override {
        for (auto&& p:values) {
            if (p.second.isImpossible())
                return false;
            p.second.changeKnownToPossible();
        }
        return true;
    }
    bool lowerToInconclusive() override {
        for (auto&& p:values) {
            if (p.second.isImpossible())