1

Im building a contract that uses two contracts that both use the ERC721 zeppelin contract, when I import the two as such:

import nonFungableWidthAddedFunctionality1.sol;
import nonFungableWidthAddedFunctionality2.sol;

I get the following error:

$PATH DeclarationError: Identifier already declared.
import "./../nonFungableWidthAddedFunctionality2.sol";
^--------------------------^
$PATH The previous declaration is here:
contract ERC721 {
^

Both of these contracts need the ERC721 implementation since they are also used separately.

  • 1
    If you just need to call the ERC721 functions from your third contract, you can just import the ERC721 definition, instead of the individual token contracts. – Raghav Sood Aug 1 '18 at 10:51
  • But both the tokens have different implementations and augmentations of the standard ERC721 protocol. – jasper Aug 1 '18 at 11:09
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    Your solution did work after looking through the ERC721 interface a bit more careful, thank you! – jasper Aug 1 '18 at 12:14
0

You are declaring contract ERC721 more than once, thus the error.

Essentially, you're doing this:

contract Contract1 {
}

contract Contract1 {
}

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