0

i have this basic contract that should work, but it keeps reverting because of the approve call in the constructor, i also notice transferFrom calls from my contract also fails after manually approving, what could be wrong.

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.4.22 <0.7.0;


interface IaToken {
    function balanceOf(address _user) external view returns (uint256);
    function redeem(uint256 _amount) external;
}

interface IERC20 {
    function totalSupply() external view returns(uint256);
    function balanceOf(address account) external view returns (uint256);
    function allowance(address owner, address spender) external view returns(uint256);
    function transfer(address recipient, uint256 amount) external view returns(bool);
    function approve(address spender, uint256 amount) external view returns(bool);
    function transferFrom(address sender, address recipient, uint256 amount) external view returns(bool);
}

interface IAaveLendingPool {
    function deposit(address _reserve, uint256 _amount, uint16 _referralCode) external;
}

contract AaveExample {
    IERC20 public dai = IERC20(0xFf795577d9AC8bD7D90Ee22b6C1703490b6512FD);
    IaToken public aToken = IaToken(0x58AD4cB396411B691A9AAb6F74545b2C5217FE6a);
    IAaveLendingPool public aaveLendingPool = IAaveLendingPool(0x580D4Fdc4BF8f9b5ae2fb9225D584fED4AD5375c);
    
    mapping(address => uint256) public userDepositedDai;
    
    constructor() public {
        dai.approve(address(0xB4bE310666D2f909789Fb1a2FD09a9bEB0Edd99D), type(uint256).max);
    }
    
    function userDepositDai(uint256 _amountInDai) external {
        userDepositedDai[msg.sender] = _amountInDai;
        require(dai.transferFrom(msg.sender, address(this), _amountInDai), "DAI Transfer failed!");
        aaveLendingPool.deposit(address(dai), _amountInDai, 0);
    }
    
    function userWithdrawDai(uint256 _amountInDai) external {
        require(userDepositedDai[msg.sender] >= _amountInDai, "You cannot withdraw more than deposited!");

        aToken.redeem(_amountInDai);
        require(dai.transferFrom(address(this), msg.sender, _amountInDai), "DAI Transfer failed!");
        
        userDepositedDai[msg.sender] = userDepositedDai[msg.sender] - _amountInDai;
    }
}

1 Answer 1

0

As I mentioned in Discord :), the problem is in the IERC20 interface - it mentions approve (and others) as a view function.

1
  • 1
    Thanks man, posted it here before i got your answer...
    – Prometheus
    Commented Jan 10, 2022 at 11:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.