Solidity 錯誤：無法構造包含（嵌套）映射的結構

我的solc版本：

"solc": "^0.7.1",

當我嘗試構造一個包含映射的結構時，出現此錯誤：“無法構造包含（嵌套）映射的結構”

這是我的可靠程式碼。

活動.sol

pragma solidity >=0.5.0;

contract Campaign {
   struct Request {
       string description;

       // I declared a mapping inside of a struct.
       mapping(address => bool) approvals;

   }
   constructor(uint256 minimum, address creator) {
       ...
   }

   function createRequest(string memory description) public onlyManager {
       Request memory newRequest = Request({ 

           // Here the compiler gives me an error

           description : description

       });
   }
   ...

它說

Struct containing a (nested) mapping cannot be constructed.

請幫我。

問題出在構造中，即，Request({ description: description })因此更改newRequestfrommemory到的位置storage將無濟於事。

如果您真的想讓它工作，請創建一個狀態變數，例如mapping (uint => Request) requests. 現在，在您的函式中，您可以編寫稍後將遞增的Request storage newRequest = requests[index]位置。index

有關參考，請參閱：文件

從 0.7.0 開始，如下所示：

struct Request{
           string description;
           uint value;
           address recipient;
           bool complete;
           uint approvalsCount;
           mapping(address => bool) approvals;
       }
       
   uint numRequests;
   mapping (uint => Request) requests;
   
   function createRequest (string memory description, uint value,
           address recipient) public{
               Request storage r = requests[numRequests++];
               r.description = description;
               r.value = value;
               r.recipient = recipient;
               r.complete = false;
               r.approvalsCount = 0;
           
       }

引用自：https://ethereum.stackexchange.com/questions/87451