Function isWritable

lib/vf_analyzers.cpp:275–322

    }

    virtual Action isWritable(const Token* tok, Direction d) const {
        const ValueFlow::Value* value = getValue(tok);
        if (!value)
            return Action::None;
        if (!(value->isIntValue() || value->isFloatValue() || value->isSymbolicValue() || value->isLifetimeValue()))
            return Action::None;
        const Token* parent = tok->astParent();
        // Only if its invertible
        if (value->isImpossible() && !Token::Match(parent, "+=|-=|*=|++|--"))
            return Action::None;
        if (value->isLifetimeValue()) {
            if (value->lifetimeKind != ValueFlow::Value::LifetimeKind::Iterator)
                return Action::None;
            if (!Token::Match(parent, "++|--|+="))
                return Action::None;
            return Action::Read | Action::Write;
        }
        if (parent && parent->isAssignmentOp() && astIsLHS(tok)) {
            const Token* rhs = parent->astOperand2();
            std::vector<MathLib::bigint> result = evaluateInt(rhs);
            if (!result.empty()) {
                ValueFlow::Value rhsValue{result.front()};
                Action a;
                if (!evalAssignment(*value, getAssign(parent, d), rhsValue))
                    a = Action::Invalid;
                else
                    a = Action::Write;
                if (parent->str() != "=") {
                    a |= Action::Read | Action::Incremental;
                } else {
                    if (!value->isImpossible() && value->equalValue(rhsValue))
                        a = Action::Idempotent;
                    if (tok->exprId() != 0 &&
                        findAstNode(rhs, [&](const Token* child) {
                        return tok->exprId() == child->exprId();
                    }))
                        a |= Action::Incremental;
                }
                return a;
            }
        }

        // increment/decrement
        if (Token::Match(tok->astParent(), "++|--")) {
            return Action::Read | Action::Write | Action::Incremental;
        }
        return Action::None;
    }

    virtual void writeValue(ValueFlow::Value* value, const Token* tok, Direction d) const {
        if (!value)