Error during deployment "invalid type (arg="type", value="function", version=4.0.47)"

The contract:

pragma solidity >= 0.7.0;
contract C {
    event Test(function() external);
}

when deployed produces the error

creation of C errored: Error: invalid type (arg=“type”, value=“function”, version=4.0.47)

[ricmoo]

Actually. Poking around with Solidity and the generated assembly, it looks like it uses the hash of Test(function) for the topic hash.

I’ve added this issue to track it: https://github.com/ethers-io/ethers.js/issues/1089

[ricmoo]

The function() syntax is not currently available in the human-readable ABI parser. Can you provide the topic for that event? My guess is you could probably replace the function() with bytes4, but I’m not sure whether they do that conversion when computing the topic hash.

Please feel free to open an issue on ethers GitHub to track this. If changing it to a bytes4 fixes this, I would probably recommend this as the solution for now, since adding parenthesis to the parser would complicate a lot of the LL(1) states, as the parser was hand-written.

I may switch to a Jison-based parser in the future which would make these changes much easier, but does add quite a bit of overhead to the library.