"Warning, Visibility For Constructor Is Ignored"

Support
1

Hello! This is my code,

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import “https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol”;

contract TokenName is ERC20 {
constructor(uint256 initialSupply) abstract ERC20(“TokenName”, “TokenSymbol”) {
_mint(msg.sender, initialSupply);
}
}

I get this error

Warning: Visibility for constructor is ignored. If you want the contract to be non-deployable, making it “abstract” is sufficient. → contracts/Neptune.sol:8:5: | 8 | constructor(uint256 initialSupply) public ERC20(“TokenName”, “TokenSymbol”) { | ^ (Relevant source part starts here and spans across multiple lines).

(I’ve replaced my name/symbol with “TokenName” and “TokenSymbol” as placeholders, my actual project name and .sol file name match up.)

Anyways, I then follow what it says and replace “public” with the word “abstract” and then it sparks this error.

ParserError: Expected ‘{’ but got ‘abstract’ → contracts/TokenName.sol:8:40: | 8 | constructor(uint256 initialSupply) abstract ERC20(“TokenName”, “TokenSymbol”) { | ^^^^^^^^

So, I’m not sure what to do at this point and I’ve looked at some of the links on here and can’t seem to find a very direct answer. If anyone could provide a direct answer it would be greatly appreciated, thank you!

2

Hi, welcome, :wave:

I think you should remove the abstract or public keyword from every constructor, for more details you can have a look at here: https://docs.soliditylang.org/en/v0.8.4/070-breaking-changes.html?highlight=constructor#how-to-update-your-code

1 Like
3

Hey! Took out the word, it allowed me to compile the project, now when I attempt to deploy, im met with this error.

creation of TokenName errored: Error encoding arguments: Error: invalid BigNumber string (argument=“value”, value="", code=INVALID_ARGUMENT, version=bignumber/5.1.1)

If you’re able to help that would be much appreciated, thank you!

4

When you deploy the contract, you should pass a value for the parameter initialSupply, so what did you pass for this value?

5

Hi! I’ve resorted to importing code instead, seems to have launched the token and works fine. If you’re able to offer additional help, with this set of code here;

pragma solidity ^0.8.0;

import “https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol”;

contract TokenName is ERC20 {
constructor(uint256 initialSupply) public ERC20 (“TokenName”, “TOKEN”){
_mint(msg.sender,initialSupply);
}
}

How would I add my own functions such as a transaction fee that of 10% that is able to burn 3%, send 3% to holders, 3% to liquidity, and 1% to a wallet?

Any help is always appreciated, thank you for the help thus far!