feat: have coinbase always return fee vault

integration-tests/contracts/OVMContextStorage.sol

@@ -6,12 +6,14 @@ contract OVMContextStorage {
     mapping (uint256 => uint256) public blockNumbers;
     mapping (uint256 => uint256) public timestamps;
     mapping (uint256 => uint256) public difficulty;
+    mapping (uint256 => address) public coinbases;
     uint256 public index = 0;
 
     fallback() external {
         blockNumbers[index] = block.number;
         timestamps[index] = block.timestamp;
         difficulty[index] = block.difficulty;
+        coinbases[index] = block.coinbase;
         index++;
     }
 }

integration-tests/test/ovmcontext.spec.ts

@@ -3,6 +3,7 @@ import { expect } from 'chai'
 /* Imports: External */
 import { ethers } from 'hardhat'
 import { injectL2Context } from '@eth-optimism/core-utils'
+import { predeploys } from '@eth-optimism/contracts'
 import { Contract, BigNumber } from 'ethers'
 
 /* Imports: Internal */
@@ -76,6 +77,10 @@ describe('OVM Context: Layer 2 EVM Context', () => {
       // Difficulty should always be zero.
       const difficulty = await OVMContextStorage.difficulty(i)
       expect(difficulty.toNumber()).to.equal(0)
+
+      // Coinbase should always be sequencer fee vault.
+      const coinbase = await OVMContextStorage.coinbases(i)
+      expect(coinbase).to.equal(predeploys.OVM_SequencerFeeVault)
     }
   }).timeout(150000) // this specific test takes a while because it involves L1 to L2 txs
 

l2geth/core/evm.go

@@ -23,6 +23,7 @@ import (
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/rollup/dump"
 	"github.com/ethereum/go-ethereum/rollup/rcfg"
 )
 
@@ -65,7 +66,7 @@ func NewEVMContext(msg Message, header *types.Header, chain ChainContext, author
 			Transfer:        Transfer,
 			GetHash:         GetHashFn(header, chain),
 			Origin:          msg.From(),
-			Coinbase:        beneficiary,
+			Coinbase:        dump.OvmFeeWallet, // Coinbase is the fee vault.
 			BlockNumber:     msg.L1BlockNumber(),
 			Time:            new(big.Int).SetUint64(msg.L1Timestamp()),
 			Difficulty:      new(big.Int), // Difficulty always returns zero.

l2geth/rollup/dump/constants.go

@@ -5,3 +5,4 @@ import (
 )
 
 var OvmEthAddress = common.HexToAddress("0x4200000000000000000000000000000000000006")
+var OvmFeeWallet = common.HexToAddress("0x4200000000000000000000000000000000000011")