调用super.owner（）。transfer（msg.value）给出错误

Question

I have a contract that inherits from Open Zeppelin's Ownable contract. There is a method payFees() in my contract that is expected to transfer funds to the owner of the contract. The definition of payFees is as follows

function payFees() public payable {
        require(students.has(msg.sender), "DOES NOT HAVE STUDENT ROLE");
        if(this.areFeesEnough(msg.value))
        {
            super.owner().transfer(msg.value);
            studentFees[msg.sender] = true;
        }

    }

I expect that a call to super.owner() returns the contract owner given that owner() is a public view function in the parent Ownable contract that returns the owner. Unfortunately, the code fails with the error.

             TypeError: Member "transfer" not found or not visible after argument-dependent lookup in address.
            super.owner().transfer(msg.value);

Any help is appreciated.Thank you.

Answer 1

Assuming the Ownable contract you're using is similar to https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/ownership/Ownable.sol , the issue is that owner() returns an address , but starting in Solidity 0.5, you can only transfer ether to an address payable .

You can convert by casting through uint160 first, something like this:

address(uint160(_owner)).transfer(msg.value);

Note that you can just use _owner directly or just call owner() . No need to call super.owner() unless you've overridden owner in your contract and need to make sure to call the parent contract.