报错Type Error: Identifier is not an contract 合约实例创建失败如何解决

你代码中定义的Promotion是Campaign合约内部的结构体（struct），并非独立的合约类型，而new关键字仅可用于部署新的合约实例，不能用来创建结构体实例，这就是触发Type Error: Identifier is not an contract错误的直接原因。

同时你代码还存在一个隐藏错误：不能直接在状态变量定义时通过uint budget = msg.value;赋值，状态变量初始化阶段msg.value没有有效值，需要放到合约构造函数中赋值。

根据你的业务需求可选择以下两种修复方案：

方案1：将Promotion调整为独立合约（适配原代码部署新实例、转账的逻辑） #

如果你需要每个Promotion都有独立的合约地址、可以接收ETH，就把Promotion抽为独立合约：

// 独立的Promotion合约
contract Promotion {
    string public description;
    uint public max_influencer;
    uint public jobvalue;
    bool public achievement;

    constructor(string memory _description, uint _jobvalue, uint _max_influencer) payable {
        description = _description;
        jobvalue = _jobvalue;
        max_influencer = _max_influencer;
        achievement = false;
    }
}

contract Campaign {
    Promotion[] public deployedPromotions;
    uint public budget;

    constructor() payable {
        budget = msg.value;
    }

    function createPromotion(string calldata description, uint max_influencer) public payable {
        // 部署合约时同步转账对应预算，不需要单独调用transfer
        Promotion newPromotion = new Promotion{value: budget}(description, budget, max_influencer);
        deployedPromotions.push(newPromotion);
    }

    receive() external payable {
        budget += msg.value;
    }
}

方案2：保留Promotion为结构体（适配仅需存储结构化数据的场景） #

如果你不需要Promotion有独立合约逻辑，只是要存储结构化数据，就不需要用new关键字：

contract Campaign {
    struct Promotion {
        string description;
        uint max_influencer;
        uint jobvalue;
        bool achievement;
    }
    
    Promotion[] public deployedPromotions;
    uint public budget;

    constructor() payable {
        budget = msg.value;
    }

    function createPromotion(string calldata description, uint max_influencer) public payable {
        // 直接创建结构体实例
        Promotion memory newPromotion = Promotion({
            description: description,
            max_influencer: max_influencer,
            jobvalue: budget,
            achievement: false
        });
        deployedPromotions.push(newPromotion);
    }

    receive() external payable {
        budget += msg.value;
    }
}

内容的提问来源于stack exchange，提问作者Garfield