truffle-flattener: Could not parse smart contract with "unchecked block" syntax

When I flatten a certain smart contract that uses openzeppelin’s SafeMath library I’m getting this error: Error: Could not parse @openzeppelin/contracts/utils/math/SafeMath.sol for extracting its imports: ParserError: missing ';' at '{'

Upon investigation, flattening fails when encountering an unchecked block. unchecked block is a valid solidity syntax introduced since 0.8.0, check reference here.

Sample code to reproduce the error:

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

library SafeMath {
    . . .
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }
   . . .
}

About this issue

Original URL
State: closed
Created 3 years ago
Reactions: 11
Comments: 18 (2 by maintainers)

Most upvoted comments

The problem is due to an outdated version of @solidity-parser/parser. See this PR: #81 If you can’t wait for the maintainers to rerelease the package, just fork mine, npm install, then run ./index.js MyContract.sol instead of truffle-flattener MyContract.sol.

you can also npm package, then npm install the artifact and still use truffle-flattener system wide 😃 in case you got scripts depending on it

You can also do npm i https://github.com/jplew/truffle-flattener that will replace current truffle-flattener package with branch linked in PR #81. It works fine

AymericNoel on Jul 9, 2021

The problem is due to an outdated version of @solidity-parser/parser. See this PR: https://github.com/nomiclabs/truffle-flattener/pull/81

If you can’t wait for the maintainers to rerelease the package, just clone mine, npm install, then run ./index.js MyContract.sol instead of truffle-flattener MyContract.sol.

jplew on Jul 10, 2021

The problem is due to an outdated version of @solidity-parser/parser. See this PR: #81

If you can’t wait for the maintainers to rerelease the package, just fork mine, npm install, then run ./index.js MyContract.sol instead of truffle-flattener MyContract.sol.

you can also npm package, then npm install the artifact and still use truffle-flattener system wide 😃 in case you got scripts depending on it

fedeb95 on Jul 9, 2021

I still got the same issue today. I’m using the truffle-flattener 1.5.0 now

baoduy on Jan 19, 2022

The problem is due to an outdated version of @solidity-parser/parser. See this PR: #81 If you can’t wait for the maintainers to rerelease the package, just fork mine, npm install, then run ./index.js MyContract.sol instead of truffle-flattener MyContract.sol.

you can also npm package, then npm install the artifact and still use truffle-flattener system wide 😃 in case you got scripts depending on it

You can also do npm i https://github.com/jplew/truffle-flattener that will replace current truffle-flattener package with branch linked in PR #81. It works fine

This is not working as I am getting the same error

harsh-im on Jul 23, 2021

The parser lib (dependency) is outdated. Those PRs need to be merged to upgrade it. This one should work https://github.com/ngduc/flatten-sol

ngduc on Jul 16, 2021