ParserError: Source "@openzeppelin/contracts/token/ERC20/ERC20.sol" not found:

Question

I keep getting this error, would be really cool to get help. I've heard that I need to install a program, forgot which but I'm not so sure that's a great idea to start with and is not the fix to this issue. I've tried to verify the contract but been without results.

Here's the issue:

: ParserError: Source "@openzeppelin/contracts/token/ERC20/ERC20.sol" not found: File import callback not supported
 --> myc:4:1:
  |
4 | import "@openzeppelin/contracts/token/ERC20/ERC20.sol"
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

And this is my code (took away the name for security reasons):

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract secret is ERC20 {
    constructor(uint256 initialsupply) public ERC20 ("secret", "secret") {
        _mint(msg.sender, initialSupply);
    }
}

Answer 1

Try using

import "OpenZeppelin/ope[email protected]/contracts/token/ERC20/ERC20.sol";

'@' is not required anymore you can specify the same in your .yaml files(remappings).

Answer 2

To import an OpenZepplin contract from Remix you have to import using the full github URL.

For example to import contracts from v4.4.0 this will work.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.4.0/contracts/token/ERC20/ERC20.sol";


contract MyToken is ERC20 {
    constructor(uint256 initialSupply) ERC20("NOMNOM", "MON") {
        _mint(msg.sender, initialSupply);
    }
}