fix(interfaces): add ISingleMessageDispatcher

src/ethereum-arbitrum/EthereumToArbitrumDispatcher.sol

@@ -4,7 +4,12 @@ pragma solidity ^0.8.16;
 import { IInbox } from "@arbitrum/nitro-contracts/src/bridge/IInbox.sol";
 
 import { IMessageExecutor } from "../interfaces/IMessageExecutor.sol";
-import { IMessageDispatcher, IBatchMessageDispatcher, IMessageDispatcherArbitrum } from "../interfaces/extensions/IMessageDispatcherArbitrum.sol";
+import {
+  IMessageDispatcher,
+  ISingleMessageDispatcher,
+  IBatchMessageDispatcher,
+  IMessageDispatcherArbitrum
+} from "../interfaces/extensions/IMessageDispatcherArbitrum.sol";
 
 import { MessageLib } from "../libraries/MessageLib.sol";
 
@@ -295,7 +300,7 @@ contract MessageDispatcherArbitrum is IMessageDispatcherArbitrum {
     return _getMessageBatchTxHash(_messageId, _from, _messages);
   }
 
-  /// @inheritdoc IMessageDispatcher
+  /// @inheritdoc ISingleMessageDispatcher
   function getMessageExecutorAddress(uint256 _toChainId) external view returns (address) {
     _checkToChainId(_toChainId);
     return address(executor);

src/ethereum-optimism/EthereumToOptimismDispatcher.sol

@@ -4,7 +4,12 @@ pragma solidity ^0.8.16;
 import { ICrossDomainMessenger } from "../vendor/optimism/ICrossDomainMessenger.sol";
 
 import { IMessageExecutor } from "../interfaces/IMessageExecutor.sol";
-import { IMessageDispatcher, IBatchMessageDispatcher, IMessageDispatcherOptimism } from "../interfaces/extensions/IMessageDispatcherOptimism.sol";
+import {
+  IMessageDispatcher,
+  ISingleMessageDispatcher,
+  IBatchMessageDispatcher,
+  IMessageDispatcherOptimism
+} from "../interfaces/extensions/IMessageDispatcherOptimism.sol";
 
 import { MessageLib } from "../libraries/MessageLib.sol";
 
@@ -86,7 +91,7 @@ contract MessageDispatcherOptimism is IMessageDispatcherOptimism {
     return _dispatchMessageBatch(_toChainId, _messages, _gasLimit);
   }
 
-  /// @inheritdoc IMessageDispatcher
+  /// @inheritdoc ISingleMessageDispatcher
   function getMessageExecutorAddress(uint256 _toChainId) external view returns (address) {
     return _getMessageExecutorAddress(_toChainId);
   }

src/ethereum-polygon/EthereumToPolygonDispatcher.sol

@@ -3,7 +3,11 @@ pragma solidity ^0.8.16;
 
 import { FxBaseRootTunnel } from "@maticnetwork/fx-portal/contracts/tunnel/FxBaseRootTunnel.sol";
 
-import { IMessageDispatcher, IBatchMessageDispatcher } from "../interfaces/extensions/IBatchMessageDispatcher.sol";
+import {
+  IMessageDispatcher,
+  ISingleMessageDispatcher,
+  IBatchMessageDispatcher
+} from "../interfaces/extensions/IBatchMessageDispatcher.sol";
 
 import { MessageLib } from "../libraries/MessageLib.sol";
 
@@ -78,7 +82,7 @@ contract MessageDispatcherPolygon is IBatchMessageDispatcher, FxBaseRootTunnel {
     return _messageId;
   }
 
-  /// @inheritdoc IMessageDispatcher
+  /// @inheritdoc ISingleMessageDispatcher
   function getMessageExecutorAddress(uint256 _chainId) external view returns (address) {
     _checkToChainId(_chainId);
     return address(fxChildTunnel);

src/interfaces/IMessageDispatcher.sol

@@ -36,12 +36,4 @@ interface IMessageDispatcher {
     address to,
     bytes calldata data
   ) external returns (bytes32);
-
-  /**
-   * @notice Retrieves address of the MessageExecutor contract on the receiving chain.
-   * @dev Must revert if `toChainId` is not supported.
-   * @param toChainId ID of the chain with which MessageDispatcher is communicating
-   * @return MessageExecutor contract address
-   */
-  function getMessageExecutorAddress(uint256 toChainId) external returns (address);
 }

src/interfaces/extensions/IBatchMessageDispatcher.sol

@@ -1,15 +1,14 @@
 // SPDX-License-Identifier: GPL-3.0
 pragma solidity ^0.8.16;
 
-import { IMessageDispatcher } from "../IMessageDispatcher.sol";
+import { IMessageDispatcher, ISingleMessageDispatcher } from "./ISingleMessageDispatcher.sol";
 import { MessageLib } from "../../libraries/MessageLib.sol";
 
 /**
- * @title ERC-5164: Cross-Chain Execution Standard, optional BatchMessageDispatcher extension
- * @dev IMessageDispatcher interface extended to support batch messaging.
- * @dev See https://eips.ethereum.org/EIPS/eip-5164
+ * @title BatchMessageDispatcher interface
+ * @dev ISingleMessageDispatcher interface extended to support batch messaging.
  */
-interface IBatchMessageDispatcher is IMessageDispatcher {
+interface IBatchMessageDispatcher is ISingleMessageDispatcher {
   /**
    * @notice Emitted when a batch of messages has successfully been dispatched to the executor chain.
    * @param messageId ID uniquely identifying the messages

src/interfaces/extensions/IMessageDispatcherArbitrum.sol

@@ -1,12 +1,16 @@
 // SPDX-License-Identifier: GPL-3.0
 pragma solidity ^0.8.16;
 
-import { MessageLib, IMessageDispatcher, IBatchMessageDispatcher } from "./IBatchMessageDispatcher.sol";
+import {
+  MessageLib,
+  IMessageDispatcher,
+  ISingleMessageDispatcher,
+  IBatchMessageDispatcher
+} from "./IBatchMessageDispatcher.sol";
 
 /**
- * @title ERC-5164: Cross-Chain Execution Standard
- * @dev IMessageDispatcher interface extended to support Arbitrum two steps message dispatch.
- * @dev See https://eips.ethereum.org/EIPS/eip-5164
+ * @title MessageDispatcherArbitrum interface
+ * @dev IBatchMessageDispatcher interface extended to support Arbitrum two steps message dispatch.
  */
 interface IMessageDispatcherArbitrum is IBatchMessageDispatcher {
   /**

src/interfaces/extensions/IMessageDispatcherOptimism.sol

@@ -1,12 +1,16 @@
 // SPDX-License-Identifier: GPL-3.0
 pragma solidity ^0.8.16;
 
-import { MessageLib, IMessageDispatcher, IBatchMessageDispatcher } from "./IBatchMessageDispatcher.sol";
+import {
+  MessageLib,
+  IMessageDispatcher,
+  ISingleMessageDispatcher,
+  IBatchMessageDispatcher
+} from "./IBatchMessageDispatcher.sol";
 
 /**
- * @title ERC-5164: Cross-Chain Execution Standard
- * @dev IMessageDispatcher interface extended to support a custom gas limit for Optimism.
- * @dev See https://eips.ethereum.org/EIPS/eip-5164
+ * @title MessageDispatcherOptimism interface
+ * @dev IBatchMessageDispatcher interface extended to support a custom gas limit for Optimism.
  */
 interface IMessageDispatcherOptimism is IBatchMessageDispatcher {
   /**

src/interfaces/extensions/ISingleMessageDispatcher.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity ^0.8.16;
+
+import { IMessageDispatcher } from "../IMessageDispatcher.sol";
+
+/**
+ * @title SingleMessageDispatcher interface
+ * @dev IMessageDispatcher interface extended to retrieve the MessageExecutor contract address.
+ */
+interface ISingleMessageDispatcher is IMessageDispatcher {
+  /**
+   * @notice Retrieves address of the MessageExecutor contract on the receiving chain.
+   * @dev Must revert if `toChainId` is not supported.
+   * @param toChainId ID of the chain with which MessageDispatcher is communicating
+   * @return MessageExecutor contract address
+   */
+  function getMessageExecutorAddress(uint256 toChainId) external returns (address);
+}