Cleanup comments

Issues have been created for those
- https://github.com/celo-org/optimism/issues/74
- https://github.com/celo-org/optimism/issues/76

contracts/fee_currencies.go

@@ -20,7 +20,6 @@ const (
 	// Default intrinsic gas cost of transactions paying for gas in alternative currencies.
 	// Calculated to estimate 1 balance read, 1 debit, and 4 credit transactions.
 	IntrinsicGasForAlternativeFeeCurrency uint64 = 50 * Thousand
-	// TODO(pl): where top put this best
 )
 
 var (
@@ -52,29 +51,16 @@ func DebitFees(evm *vm.EVM, address common.Address, amount *big.Int, feeCurrency
 	if amount.Cmp(big.NewInt(0)) == 0 {
 		return nil
 	}
-
-	// Run only primary evm.Call() with tracer
-	// if evm.GetDebug() {
-	// 	evm.SetDebug(false)
-	// 	defer func() { evm.SetDebug(true) }()
-	// }
-
-	// Transfer is a paid mutator transaction binding the contract method 0xa9059cbb.
-	//
-	// Solidity: function transfer(address to, uint256 amount) returns(bool)
-	// transferSelector := hexutil.MustDecode("0xa9059cbb")
-	// transferData := common.GetEncodedAbi(transferSelector, [][]byte{common.AddressToAbi(tmpAddress), common.AmountToAbi(amount)})
-
 	abi, err := abigen.FeeCurrencyMetaData.GetAbi()
 	if err != nil {
 		return err
 	}
+	// Solidity: function transfer(address to, uint256 amount) returns(bool)
 	input, err := abi.Pack("transfer", tmpAddress, amount)
 	if err != nil {
 		return err
 	}
 
-	// create account ref
 	caller := vm.AccountRef(address)
 
 	_, leftoverGas, err := evm.Call(caller, *feeCurrency, input, maxGasForDebitGasFeesTransactions, big.NewInt(0))
@@ -92,23 +78,14 @@ func CreditFees(
 	tipTxFee *big.Int,
 	baseTxFee *big.Int,
 	feeCurrency *common.Address) error {
-	// Run only primary evm.Call() with tracer
-	// if evm.GetDebug() {
-	// 	evm.SetDebug(false)
-	// 	defer func() { evm.SetDebug(true) }()
-	// }
-
 	caller := vm.AccountRef(tmpAddress)
 
-	// Transfer is a paid mutator transaction binding the contract method 0xa9059cbb.
-	//
-	// Solidity: function transfer(address to, uint256 amount) returns(bool)
-	// transferSelector := hexutil.MustDecode("0xa9059cbb")
 	abi, err := abigen.FeeCurrencyMetaData.GetAbi()
 	if err != nil {
 		return err
 	}
 
+	// Solidity: function transfer(address to, uint256 amount) returns(bool)
 	transfer1Data, err := abi.Pack("transfer", from, refund)
 	if err != nil {
 		return err

core/state_transition.go

@@ -536,9 +536,8 @@ func (st *StateTransition) innerTransitionDb() (*ExecutionResult, error) {
 		contractCreation = msg.To == nil
 	)
 
-	// TODO(pl) Decide if we want to read this from the chain?
-	gasForAlternativeCurrency := uint64(0)
 	// If the fee currency is nil, do not retrieve the intrinsic gas adjustment from the chain state, as it will not be used.
+	gasForAlternativeCurrency := uint64(0)
 	if msg.FeeCurrency != nil {
 		gasForAlternativeCurrency = fee_currencies.IntrinsicGasForAlternativeFeeCurrency
 	}
@@ -661,12 +660,6 @@ func (st *StateTransition) blobGasUsed() uint64 {
 
 // distributeTxFees calculates the amounts and recipients of transaction fees and credits the accounts.
 func (st *StateTransition) distributeTxFees() error {
-	// TODO(pl): check tracing
-	// Run only primary evm.Call() with tracer
-	// if st.evm.GetDebug() {
-	// 	st.evm.SetDebug(false)
-	// 	defer func() { st.evm.SetDebug(true) }()
-	// }
 	if st.evm.Config.NoBaseFee && st.msg.GasFeeCap.Sign() == 0 && st.msg.GasTipCap.Sign() == 0 {
 		// Skip fee payment when NoBaseFee is set and the fee fields
 		// are 0. This avoids a negative effectiveTip being applied to