fix(contracts): remove payable from relayCalls

README.md

@@ -13,7 +13,7 @@ To use ERC-5164 to send messages your contract code will need to:
 - On the sending chain, send a batch of calls to the CrossChainRelayer `relayCalls` function
 - Listen for calls from the corresponding CrossChainExecutor(s) on the receiving chain.
 
-*The listener will need to be able to unpack the original sender address (it's appended to calldata). We recommend inheriting from the included [`ExecutorAware.sol`](./src/abstract/ExecutorAware.sol) contract.*
+_The listener will need to be able to unpack the original sender address (it's appended to calldata). We recommend inheriting from the included [`ExecutorAware.sol`](./src/abstract/ExecutorAware.sol) contract._
 
 **Note**
 

src/ethereum-arbitrum/EthereumToArbitrumRelayer.sol

@@ -66,7 +66,6 @@ contract CrossChainRelayerArbitrum is ICrossChainRelayer {
   /// @inheritdoc ICrossChainRelayer
   function relayCalls(CallLib.Call[] calldata _calls, uint256 _gasLimit)
     external
-    payable
     returns (uint256)
   {
     uint256 _maxGasLimit = maxGasLimit;

src/ethereum-optimism/EthereumToOptimismRelayer.sol

@@ -48,7 +48,6 @@ contract CrossChainRelayerOptimism is ICrossChainRelayer {
   /// @inheritdoc ICrossChainRelayer
   function relayCalls(CallLib.Call[] calldata _calls, uint256 _gasLimit)
     external
-    payable
     returns (uint256)
   {
     uint256 _maxGasLimit = maxGasLimit;

src/ethereum-polygon/EthereumToPolygonRelayer.sol

@@ -44,7 +44,6 @@ contract CrossChainRelayerPolygon is ICrossChainRelayer, FxBaseRootTunnel {
   /// @inheritdoc ICrossChainRelayer
   function relayCalls(CallLib.Call[] calldata _calls, uint256 _gasLimit)
     external
-    payable
     returns (uint256)
   {
     uint256 _maxGasLimit = maxGasLimit;

src/interfaces/ICrossChainRelayer.sol

@@ -7,6 +7,7 @@ import "../libraries/CallLib.sol";
 /**
  * @title CrossChainRelayer interface
  * @notice CrossChainRelayer interface of the ERC-5164 standard as defined in the EIP.
+ * @dev Use `ICrossChainRelayerPayable` if the bridge you want to integrate requires a payment in the native currency.
  */
 interface ICrossChainRelayer {
   /**
@@ -35,13 +36,9 @@ interface ICrossChainRelayer {
    * @notice Relay the calls to the receiving chain.
    * @dev Must increment a `nonce` so that the batch of calls can be uniquely identified.
    * @dev Must emit the `RelayedCalls` event when successfully called.
-   * @dev May require payment. Some bridges may require payment in the native currency, so the function is payable.
    * @param calls Array of calls being relayed
    * @param gasLimit Maximum amount of gas required for the `calls` to be executed
    * @return uint256 Nonce to uniquely idenfity the batch of calls
    */
-  function relayCalls(CallLib.Call[] calldata calls, uint256 gasLimit)
-    external
-    payable
-    returns (uint256);
+  function relayCalls(CallLib.Call[] calldata calls, uint256 gasLimit) external returns (uint256);
 }

src/interfaces/ICrossChainRelayerPayable.sol

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-3.0
+
+pragma solidity 0.8.16;
+
+import "../libraries/CallLib.sol";
+
+/**
+ * @title CrossChainRelayer interface
+ * @notice CrossChainRelayer interface of the ERC-5164 standard as defined in the EIP.
+ */
+interface ICrossChainRelayerPayable {
+  /**
+   * @notice Custom error emitted if the `gasLimit` passed to `relayCalls`
+   *         is greater than the one provided for free on the receiving chain.
+   * @param gasLimit Gas limit passed to `relayCalls`
+   * @param maxGasLimit Gas limit provided for free on the receiving chain
+   */
+  error GasLimitTooHigh(uint256 gasLimit, uint256 maxGasLimit);
+
+  /**
+   * @notice Emitted when calls have successfully been relayed to the executor chain.
+   * @param nonce Nonce to uniquely idenfity the batch of calls
+   * @param sender Address of the sender
+   * @param calls Array of calls being relayed
+   * @param gasLimit Maximum amount of gas required for the `calls` to be executed
+   */
+  event RelayedCalls(
+    uint256 indexed nonce,
+    address indexed sender,
+    CallLib.Call[] calls,
+    uint256 gasLimit
+  );
+
+  /**
+   * @notice Relay the calls to the receiving chain.
+   * @dev Must increment a `nonce` so that the batch of calls can be uniquely identified.
+   * @dev Must emit the `RelayedCalls` event when successfully called.
+   * @dev May require payment. Some bridges requires payment in the native currency, so the function is payable.
+   * @param calls Array of calls being relayed
+   * @param gasLimit Maximum amount of gas required for the `calls` to be executed
+   * @return uint256 Nonce to uniquely idenfity the batch of calls
+   */
+  function relayCalls(CallLib.Call[] calldata calls, uint256 gasLimit)
+    external
+    payable
+    returns (uint256);
+}