EIP-712: eth_signTypedData as a standard for machine-verifiable and human-readable typed data signing

EIPs
30

The current draft of EIP-712 says:

Specification of the eth_signTypedData JSON RPC

The method eth_signTypedData is added to the Ethereum JSON-RPC. The method parallels eth_sign.

eth_signTypedData

The sign method calculates an Ethereum specific signature with: sign(keccak256("\x19Ethereum Signed Message:\n" + len(message) + message))).

I don’t understand the last line. Isn’t this supposed to be

sign(keccak256("\x19\x01" + domainSeparator + hashStruct(message)))

instead, as described in the “Specification” section above? The listed
definition describes eth_sign, not the new eth_signTypedData, and
does not seem consistent with Ethers’s TypedDataEncoder.encode (as
used in the Wallet implementation of Signer._signTypedData), nor
with OpenZeppelin’s ECDSA.toTypedDataHash.

Is this a copy-paste error in the spec, or am I missing something?

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