Hey, i just started using WSL on VS Code.
Before that, 5mins ago i was using normal windows environment.
In both the environments, i am unable to compile my truffle project and it looks like and error in the openzepplin .sol file’s import statements.
Can you help?
Hi @Rahul_Gupta,
Welcome to the community 
I’m sorry that you are having this issue when compiling with Truffle.
I am using WSL2 and wasn’t able to reproduce what you are seeing.
pragma solidity ^0.6.0;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
contract GLDToken is ERC20 {
constructor(uint256 initialSupply) ERC20("Gold", "GLD") public {
_mint(msg.sender, initialSupply);
}
}
$ npx truffle compile
Compiling your contracts...
===========================
> Compiling ./contracts/GLDToken.sol
> Compiling ./contracts/Migrations.sol
> Compiling @openzeppelin/contracts/GSN/Context.sol
> Compiling @openzeppelin/contracts/math/SafeMath.sol
> Compiling @openzeppelin/contracts/token/ERC20/ERC20.sol
> Compiling @openzeppelin/contracts/token/ERC20/IERC20.sol
> Compiling @openzeppelin/contracts/utils/Address.sol
> Artifacts written to /home/abcoathup/projects/forum/rahul_gupta/build/contracts
> Compiled successfully using:
- solc: 0.6.7+commit.b8d736ae.Emscripten.clang
Would you mind running npx truffle version (if truffle installed locally) or truffle version if installed globally.
I have the following versions:
$ npx truffle version
Truffle v5.1.26 (core: 5.1.26)
Solidity - 0.6.7 (solc-js)
Node v10.19.0
Web3.js v1.2.1
How are you running the compile?
I use npx truffle compile.
Hi @Rahul_Gupta,
I wanted to check if you were able to resolve? Please ask all the questions that you need.
Having the same problem. Compiler isn't recognizing imports at all.
<
pragma solidity ^0.5.0;
pragma experimental ABIEncoderV2;
// Import money-legos contracts
import "@studydefi/money-legos/aave/contracts/ILendingPool.sol";
import "@studydefi/money-legos/aave/contracts/IFlashLoanReceiver.sol";
import "@studydefi/money-legos/aave/contracts/FlashloanReceiverBase.sol";
import "@studydefi/money-legos/uniswap/contracts/IUniswapFactory.sol";
import "@studydefi/money-legos/uniswap/contracts/IUniswapExchange.sol";
// Import Openzeppelin contracts
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
contract FlashloanMoneyLego is FlashLoanReceiverBase {
address public constant AaveLendingPoolAddressProviderAddress = 0x506B0B2CF20FAA8f38a4E2B524EE43e1f4458Cc5;
address public constant BAT_ADDRESS = 0x2d12186Fbb9f9a8C28B3FfdD4c42920f8539D738;
address public constant UNISWAP_FACTORY_A = 0xECc6C0542710a0EF07966D7d1B10fA38bbb86523;
address public constant UNISWAP_FACTORY_B = 0x54Ac34e5cE84C501165674782582ADce2FDdc8F4;
IUniswapFactory public uniswapFactoryA;
IUniswapFactory public uniswapFactoryB;
IUniswapExchange public exchangeAforLoanAsset;
IUniswapExchange public exchangeBforLoanAsset;
IUniswapExchange public exchangeAforBAT;
IUniswapExchange public exchangeBforBAT;
constructor() public {
// Override the addressesProvider in the base class to use Kovan for testing
FlashLoanReceiverBase.addressesProvider = ILendingPoolAddressesProvider(
AaveLendingPoolAddressProviderAddress
);
// Instantiate Uniswap Factory A & B
uniswapFactoryA = IUniswapFactory(UNISWAP_FACTORY_A);
uniswapFactoryB = IUniswapFactory(UNISWAP_FACTORY_B);
// get Exchange B Address
address addressForBATExchangeA = uniswapFactoryA.getExchange(BAT_ADDRESS);
address addressForBATExchangeB = uniswapFactoryB.getExchange(BAT_ADDRESS);
// Instantiate Exchange B for BAT Token swaps
exchangeAforBAT = IUniswapExchange(addressForBATExchangeA);
exchangeBforBAT = IUniswapExchange(addressForBATExchangeB);
}
function executeOperation(
address _reserve,
uint _amount,
uint _fee,
bytes calldata _params
) external {
require(_amount <= getBalanceInternal(address(this), _reserve), "Invalid balance, was the flashLoan successful?");
address RESERVE_ADDRESS = _reserve;
uint256 deadline = now + 3000;
// get Exchange Address for the reserve asset
address addressForLoanAssetExchangeA = uniswapFactoryA.getExchange(RESERVE_ADDRESS);
address addressForLoanAssetExchangeB = uniswapFactoryB.getExchange(RESERVE_ADDRESS);
// Instantiate Exchange A
exchangeAforLoanAsset = IUniswapExchange(addressForLoanAssetExchangeA);
exchangeBforLoanAsset = IUniswapExchange(addressForLoanAssetExchangeB);
IERC20 loan = IERC20(RESERVE_ADDRESS);
IERC20 bat = IERC20(BAT_ADDRESS);
// Swap the reserve asset (e.g. DAI) for BAT
require(loan.approve(address(exchangeBforLoanAsset), _amount), "Could not approve reserve asset sell");
uint256 batPurchased = exchangeBforLoanAsset.tokenToTokenSwapInput(
_amount,
1,
1,
deadline,
BAT_ADDRESS
);
require(bat.approve(address(exchangeAforBAT), batPurchased), "Could not approve BAT asset sell");
// Swap BAT back to the reserve asset (e.g. DAIs)
uint256 reserveAssetPurchased = exchangeAforBAT.tokenToTokenSwapInput(
batPurchased,
1,
1,
deadline,
RESERVE_ADDRESS
);
uint amount = _amount;
uint totalDebt = amount.add(_fee);
require(reserveAssetPurchased > totalDebt, "There is no profit! Reverting!");
transferFundsBackToPoolInternal(RESERVE_ADDRESS, amount.add(_fee));
}
// Entry point for flashloan
function initateFlashLoan(
address assetToFlashLoan,
uint amountToLoan
) external {
bytes memory data = "";
// Get Aave lending pool
ILendingPool lendingPool = ILendingPool(addressesProvider.getLendingPool());
IERC20 loan = IERC20(assetToFlashLoan);
// Ask for a flashloan
lendingPool.flashLoan(
address(this),
assetToFlashLoan,
amountToLoan,
data
);
// If there is still a balance of the loan asset then this is profit to be returned to sender!
uint256 profit = loan.balanceOf(address(this));
require(loan.transfer(msg.sender, profit), "Could not transfer back the profit");
}
}
Fixed it with relative link:
‘import “…/node_modules/@studydefi/money-legos/aave/contracts/ILendingPool.sol”;’
Probably not best practice but it’ll do.