Cannot override _afterTokenTransfer hook in ERC721 contract

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1

Hi everybody,

I'm trying to override the _afterTokenTransfer hook method in ERC721 token contract, but unfortunately it seems that the method is not available because I get a compilation error (I'm using version @4.4.2).

This is my code:

function _afterTokenTransfer(address from, address to, uint256 tokenId)
        internal
        virtual
        override
    {
        super._afterTokenTransfer(address from, address to, uint256 tokenId);
        _approve(from, tokenId);
        _pause();
    }

And this is the error:

CompilerError: solc returned the following errors:

TypeError: Function has override specified but does not override anything.

Is this because the method is not implemented in this version?
Am I missing something?

thank you in advance for your help :slight_smile:

1 Like
2

I have a similar issue. I suspect it's a version issue. Looking at the OpenZeppelin github, some versions of ERC721.sol don't have a definition for the _afterTokenTransfer function, including maybe the latest ones included in my project (building with the React Truffle Box). I don't really understand how to pull in a good version, but will update you if I figure that out.

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3

Hi @mattlandau. I found the "solution". In version 4.4.2 _afterTokenTransfer hook was not implemented in ERC721.sol. With the latest version 4.5.0-rc.0 the issue is solved. I suppose in the next weeks the stable 4.5.0 version will be available and everything will work as expected :wink:

Thank you very much for your reply!

1 Like
4

Hi, welcome! :wave:

Yeah, you are right, you can use the version 4.5.0-rc.0 currently.

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