EIP-1898 Support

[omarsayha]

Note: The best place to start a Feature Request is usually in the Discussions, to mull through the desired feature, current options and think through the impact on the library overall.

Is your feature request related to a problem? Please describe.
Geth added support for https://eips.ethereum.org/EIPS/eip-1898 in the following PR ethereum/go-ethereum#19491

Describe the solution you'd like

The following methods should currently accept blockTag?: BlockTag | Promise:

getBalance
getStorageAt
getTransactionCount
getCode
call
getProof

In addition to a blockTag, it should also accept something like:

export interface BlockHashEIP1898 {
    blockHash: string;
    requireCanonical: boolean;
}

Describe alternatives you've considered
I can always use provider.send to call a method that conforms to eip-1898, but it would be nice if this were built into the library.

Additional context
Add any other context or screenshots about the feature request here.

[ricmoo]

Those methods (the ones that ethers includes in the Provider) should already support blockHash on backends that support it. I am unfamiliar with the requireCanonical key; what is it for?

Do you have an example where it does not work?

[avsetsin]

Do you have an example where it does not work?

Alchemy requires compliance with EIP-1898 and doesn't work when you try to pass block hash as a string. A simple example to demonstrate: https://codesandbox.io/s/eip-1898-0ln6yl

[wighawag]

I have the same issue as @avsetsin

I get

{"jsonrpc":"2.0","error":{"code":-32602,"message":"invalid 2nd argument: block_parameter value was not valid, see valid values at: https://eips.ethereum.org/EIPS/eip-1898"},"id":45}

For blockHash, it expect the second param to be an object {blockHash: string}

[infloop]

I have the same issue, do you need a PR for that?