Member function "transfer" not found or not visible after argument-dependent lookup in contract?

Question

I am having a problem with my smart contract making value transfers. My current environment:

Truffle v5.0.0-beta.2 (core: 5.0.0-beta.2)
Solidity v0.5.0 (solc-js)
Node v8.11.1

I created the following test function to help track down the problem:

pragma solidity ^0.4.24;

import "../node_modules/openzeppelin-solidity/contracts/math/SafeMath.sol";
import "../node_modules/openzeppelin-solidity/contracts/lifecycle/Pausable.sol";

contract EtherBandBattlesManager is Pausable {

using SafeMath for uint256;    

    function testPayment(address _payeeAddr)
            payable
            public
            onlyOwner
            {
        require(_payeeAddr != address(0), "(testPayment) The payee address is not set.");
        require(msg.value != 0, "(testPayment) The amount of value accompanying the transaction is zero.");

        // Make the payment.
        _payeeAddr.transfer(msg.value);
    }
}

Before I upgraded to Truffle 5 beta the contract compiled successfully. But when I made a call to testPayment() I did see the balance of the Ganache account I was paying from decrease, but I did not see the balance of the destination account increase.

I then upgraded to Truffle 5.0 beta.

Now I get a fatal compiler error saying:

/ether-band-battles-work/solidity/contracts/EtherBandBattlesManager.sol:1142:9: TypeError: Member "transfer" not found or not visible after argument-dependent lookup in address.
    _payeeAddr.transfer(pendingPaymentDetails.paymentAmountGwei);

My understanding is that the transfer() function was introduced in Solidity 4.1 and I am using 4.24 as you can see. Why can't the compiler find the transfer() function? Also, any comments on why I am not seeing the balance on the destination account go up after making the transfer() call would be appreciated.

Answer 1

This is due to some breaking changes in Solidity version 0.5. Namely that an address has to be marked as payable - otherwise it won't have the transfer function. More info here: https://solidity.readthedocs.io/en/v0.5.0/050-breaking-changes.html#explicitness-requirements

So just change you function parameters from address _payeeAddr to address payable _payeeAddr and it will work just fine.