Warning: This declaration shadows an existing declaration.

[vittominacori]

There are lot of Warning: This declaration shadows an existing declaration..

Is there a way to silence these warnings.

I'm using solc 0.7.4

Compilation warnings: 
contracts/token/ERC20/ERC20.sol:57:18: Warning: This declaration shadows an existing declaration.
    constructor (string memory name, string memory symbol) {
                 ^----------------^
contracts/token/ERC20/ERC20.sol:66:5: The shadowed declaration is here:
    function name() public view returns (string memory) {
    ^ (Relevant source part starts here and spans across multiple lines).

[nventuro]

Solidity 0.7.4 now properly diagnoses shadowing when it clashes with variables or functions that are only declared later on in the file.

This leads to a massive number of warnings, since Contracts has sort of relied on this and used careful ordering to avoid warnings. A compilation of Contracts itself yields 250 lines of warnings. Pretty much every user of the library gets a few of these when using 0.7.4.

[ongrid]

I confirm the issue with solc 0.7.4

pragma solidity ^0.7.0;

import "../openzeppelin-contracts/contracts/access/AccessControl.sol";
import "../openzeppelin-contracts/contracts/token/ERC20/ERC20.sol";
import "../openzeppelin-contracts/contracts/token/ERC20/ERC20Burnable.sol";
import "../openzeppelin-contracts/contracts/GSN/Context.sol";

contract Token is AccessControl, ERC20Burnable {
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");

    constructor() ERC20("Aura Token", "TKN") {
        _setupRole(MINTER_ROLE, _msgSender());
    }

    function mint(address to, uint256 amount) public virtual {
        require(hasRole(MINTER_ROLE, _msgSender()), "Need MINTER_ROLE");
        _mint(to, amount);
    }
}

$ npx oz compile --solc-version 0.7.3
✓ Compiled contracts with solc 0.7.3 (commit.9bfce1f6)

$ npx oz compile --solc-version 0.7.4
✓ Compiled contracts with solc 0.7.4 (commit.3f05b770)
Compilation warnings: 
openzeppelin-contracts/contracts/token/ERC20/ERC20.sol:57:18: Warning: This declaration shadows an existing declaration.
    constructor (string memory name, string memory symbol) {
                 ^----------------^
openzeppelin-contracts/contracts/token/ERC20/ERC20.sol:66:5: The shadowed declaration is here:
    function name() public view returns (string memory) {
    ^ (Relevant source part starts here and spans across multiple lines).

openzeppelin-contracts/contracts/token/ERC20/ERC20.sol:57:38: Warning: This declaration shadows an existing declaration.
    constructor (string memory name, string memory symbol) {
                                     ^------------------^
openzeppelin-contracts/contracts/token/ERC20/ERC20.sol:74:5: The shadowed declaration is here:
    function symbol() public view returns (string memory) {
    ^ (Relevant source part starts here and spans across multiple lines).

[frangio]

If anyone would like to provide a PR for this it would be really appreciated. I won't be able to tackle this until next week.

[frangio]

As a follow up to the number of warnings this actually produces, I'd like to clarify there is only 14 warnings due to variable shadowing. In any case, we're working on this in #2396 and it will be released as soon as possible.

[frangio]

Fixed by @zemse in #2396. Thank you!

Released now in @openzeppelin/[email protected].

[0xKarl98]

why my solc 0.8.15 still got the same error ?

[frangio]

@0xKarl98 Open a new issue.