Solidity Type "send" and "transfer" are only available for objects of type "address payable" using a payable address

Question

So, i am writing a smart contract on Solidity, and i thought my compiler was wrong or something, but i tried using Remix, Truffle and Hardhat, and them all give the same error, i don't know that i am doing wrong because i explicit declared the "Beneficiary" variable as payable, even in the constructor, can anyone help me?

    // SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

//This contract uses a "Timelock" function, please note that if you actually use it, you CANNOT withdraw funds until the set date!!!!

contract Banking {

    address public Beneficiary;
    uint256 public givenTime;

    constructor(address payable _Beneficiary, uint256 _givenTime) {
        require(_givenTime > block.timestamp); //Make sure the time is in the future.
        Beneficiary = _Beneficiary;
        givenTime = _givenTime;
    }

    function Withdraw() public {
        require(block.timestamp >= givenTime);
        address(Beneficiary).transfer(address(this).balance);
    }
}

Answer 1

2 Things are wrong:

When you init Beneficiary you didn't init him as payable like this:

address public payable Beneficiary;

And in the Withdraw() you should cast the address into payable like this:

payable(Beneficiary).transfer(address(this).balance);

Also it is not recommended to use transfer anymore because of gas restrictions, I recommend that you use call instead like this:

(bool success,) = payable(Beneficiary).call{value: address(this).balance}(""); 
require(success, "transaction failed");