Compiler Error: Invalid Implicit Conversion from Contract AggregatorV3Interface

[chapman91]

I'm encountering a compilation error in my Solidity project when using the Chainlink AggregatorV3Interface. The error message is:

The contract is designed to accept an address of a deployed AggregatorV3Interface during construction and use it for price conversion.

Code Snippet:

Steps Taken:

1. Imported the Interface: Imported AggregatorV3Interface from Chainlink's contracts.

2. Constructor: Passed the address of the price feed to the constructor.

3. Used the Interface: Called latestRoundData() from the AggregatorV3Interface.

Questions:

Why am I getting an invalid implicit conversion error when the types seem to match?

How can I ensure the AggregatorV3Interface type is consistent across my codebase?

Is there a specific version of Chainlink's contracts I should be using?

[EngrPips]

Hello @chapman91, Please show your PriceConverter library.

[chapman91]

[EngrPips]

Hello @chapman91, Make your importation of AggregatorV3Interface be from the same source in both your PriceConverter Library and your FundMe contract

[chapman91]

Hey @EngrPips, I checked and its verified that the AgggregatorV3Interface both in the Price Converter Library and FundMe contract are coming from the same place.

[EngrPips]

Hey @EngrPips, I checked and its verified that the AgggregatorV3Interface both in the Price Converter Library and FundMe contract are coming from the same place.

Please share your FundMe contract and your PriceConverter Library, Please don't send images but copy the code and send them also make sure to format them appropriately.

[chapman91]

Below you have the Fundme contract

`// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/shared/interfaces/AggregatorV3Interface.sol";
import {PriceConverter} from "./PriceConverter.sol";

error FundMe__NotOwner();

contract FundMe {
using PriceConverter for uint256;

mapping(address => uint256) public addressToAmountFunded;
address[] public funders;

address public /* immutable */ i_owner;
 
uint256 public constant MINIMUM_USD = 5 * 10 ** 18;  // ** acts as the exponentiation operator

AggregatorV3Interface private s_priceFeed;



constructor(address priceFeed) {
    s_priceFeed = AggregatorV3Interface(priceFeed);
    i_owner = msg.sender;

}

function fund() public payable {
    require(msg.value.getConversionRate(s_priceFeed) >= MINIMUM_USD, "You need to spend more ETH!");
    // require(PriceConverter.getConversionRate(msg.value) >= MINIMUM_USD, "You need to spend more ETH!");
    addressToAmountFunded[msg.sender] += msg.value;
    funders.push(msg.sender);
}
// getVersion Function
function getVersion() public view returns (uint256) {
    return s_priceFeed.version();
}

modifier onlyOwner() {
    if (msg.sender != i_owner) revert FundMe__NotOwner();
    _;
}

function withdraw() public onlyOwner {
    for (uint256 funderIndex = 0; funderIndex < funders.length; funderIndex++) {
        address funder = funders[funderIndex];
        addressToAmountFunded[funder] = 0;
    }
    funders = new address[](0);


    (bool callSuccess,) = payable(msg.sender).call{value: address(this).balance}("");
    require(callSuccess, "Call failed");
}

fallback() external payable {
    fund();
}

receive() external payable {
    fund();
}

}

Below is the PriceConverter Contract

`// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

library PriceConverter {
function getPrice(
AggregatorV3Interface priceFeed
) internal view returns (uint256) {

    (, int256 answer, , , ) = priceFeed.latestRoundData();
    // ETH/USD rate in 18 digit
    return uint256(answer * 10000000000);
}

function getConversionRate(
    uint256 ethAmount, // Amount of Ether (in wei) to be converteed
    AggregatorV3Interface priceFeed // Price feed interface to get the current ETH/USD price
) internal view returns (uint256) {
    uint256 ethPrice = getPrice(priceFeed); // Get the currenct ETH price in USD (with 18 decimals)
    uint256 ethAmountInUsd = (ethPrice * ethAmount) / 1000000000000000000; // calculate the equivalent USD value
    // the actual ETH/USD conversion rate, after adjusting the extra 0s.
    return ethAmountInUsd;
}

}
`

[EngrPips]

FUNDME CONTRACT

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/shared/interfaces/AggregatorV3Interface.sol";
import {PriceConverter} from "./PriceConverter.sol";

error FundMe__NotOwner();

contract FundMe {
using PriceConverter for uint256;

mapping(address => uint256) public addressToAmountFunded;
address[] public funders;

address public /* immutable */ i_owner;
 
uint256 public constant MINIMUM_USD = 5 * 10 ** 18;  // ** acts as the exponentiation operator

AggregatorV3Interface private s_priceFeed;



constructor(address priceFeed) {
    s_priceFeed = AggregatorV3Interface(priceFeed);
    i_owner = msg.sender;

}

function fund() public payable {
    require(msg.value.getConversionRate(s_priceFeed) >= MINIMUM_USD, "You need to spend more ETH!");
    // require(PriceConverter.getConversionRate(msg.value) >= MINIMUM_USD, "You need to spend more ETH!");
    addressToAmountFunded[msg.sender] += msg.value;
    funders.push(msg.sender);
}
// getVersion Function
function getVersion() public view returns (uint256) {
    return s_priceFeed.version();
}

modifier onlyOwner() {
    if (msg.sender != i_owner) revert FundMe__NotOwner();
    _;
}

function withdraw() public onlyOwner {
    for (uint256 funderIndex = 0; funderIndex < funders.length; funderIndex++) {
        address funder = funders[funderIndex];
        addressToAmountFunded[funder] = 0;
    }
    funders = new address[](0);


    (bool callSuccess,) = payable(msg.sender).call{value: address(this).balance}("");
    require(callSuccess, "Call failed");
}

fallback() external payable {
    fund();
}

receive() external payable {
    fund();
}
}

PRICE CONVERTER LIBRARY

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;

import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

library PriceConverter {
function getPrice(
AggregatorV3Interface priceFeed
) internal view returns (uint256) {

    (, int256 answer, , , ) = priceFeed.latestRoundData();
    // ETH/USD rate in 18 digit
    return uint256(answer * 10000000000);
}

function getConversionRate(
    uint256 ethAmount, // Amount of Ether (in wei) to be converteed
    AggregatorV3Interface priceFeed // Price feed interface to get the current ETH/USD price
) internal view returns (uint256) {
    uint256 ethPrice = getPrice(priceFeed); // Get the currenct ETH price in USD (with 18 decimals)
    uint256 ethAmountInUsd = (ethPrice * ethAmount) / 1000000000000000000; // calculate the equivalent USD value
    // the actual ETH/USD conversion rate, after adjusting the extra 0s.
    return ethAmountInUsd;
}
}

[EngrPips]

The path you imported AggregatorV3Interface from in your FundMe contract is import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/shared/interfaces/AggregatorV3Interface.sol";. In contrast, the path you imported AggregatorV3Interface from in your PriceConverter Library is import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol"; They are not the same, Please kindly make use of one path in both the FundMe contract and PriceConverter Library.

[chapman91]

Thank you. I bypassed the error. Learnt a lesson to look closer next time!

[EngrPips]

Indeed, Programming is always teaching us a lot.