LegacyMessagePasser.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.15;

import { ISemver } from "src/universal/ISemver.sol";

/// @custom:legacy
/// @custom:proxied
/// @custom:predeploy 0x4200000000000000000000000000000000000000
/// @title LegacyMessagePasser
/// @notice The LegacyMessagePasser was the low-level mechanism used to send messages from L2 to L1
///         before the Bedrock upgrade. It is now deprecated in favor of the new MessagePasser.
contract LegacyMessagePasser is ISemver {
    /// @notice Mapping of sent message hashes to boolean status.
    mapping(bytes32 => bool) public sentMessages;

    /// @notice Semantic version.
    /// @custom:semver 1.1.0
    string public constant version = "1.1.0";

    /// @notice Passes a message to L1.
    /// @param _message Message to pass to L1.
    function passMessageToL1(bytes memory _message) external {
        sentMessages[keccak256(abi.encodePacked(_message, msg.sender))] = true;
    }
}