Tried to run: 1.) Dappuniversity project (dappuniversity/dbank) 2.) pet-shop-tutorial Truffle v5.3.3 (core: 5.3.3) Node v14.15.5 How can ser compile code @ the 0.8.4 to import OpenZeppelin’s ERC20....

I'm trying to get started with what should be a very simple Solidity contract but VSCode is giving me a hard time. I'm using Juan Blancos solidity plugin but VSCode cannot find openzepplin imports ...

I've imported the Open Zeppelin ERC721 token standard into my VS Code with the Solidity extension, but see the following warnings on all my OZ import statements: Screenshot of error Why is this hap...

Whenever I try to compile my solidity contract, the error ParserError: Source \"@OpenZeppelin/contracts/math/SafeMath.sol\" not found: File import callback not supported gets thrown. prag...

I am trying to verify my contract with arguments and I am getting this error: Error in plugin @nomiclabs/hardhat-etherscan: The contract verification failed. Reason: Fail - Unable to verify I am ...

I'm having a hard time understanding why and when SetApprovalForAll is called on NFT generating contracts. Take Cool Cats, for example. And for convenience there's a screen shot of relevant transac...

I created a contract instance in hardhat console like so: const contract_fac = await ethers.getContractFactory("ContractName"); const contract = await contract_fac.attach("CONTRACTAD...

This has been a problem I've been dealing with for a while now. My temporary solution has been to create a SafeMath.sol file in my Contracts directory and directly import it from there. However, I'...

I've faced an ethers signature unmatched problem. Everything is normal. Already compared domainData, types, message variable in the js code with contract. Below is the JS Code to generate signature...

I'm testing a smart contract for an ERC721 token, that inherits from OpenZeppelin, using waffle and chai with NodeJS v14.18.0, but chai's reverted assertions don't seem to function as expected. Dep...

For smart contract development, what is the difference between Openzeppelin SDK and Truffle? When should I use one or another, or both together?

pragma solidity ^0.4.15; import './ERC20.sol'; import './SafeMath.sol'; How connect SafeMath.sol from external(non-local) resourses?