refactor(evm): Remove duplicate defined variables (#559)

Refactor: Remove duplicate defined variables

core/state_transition.go

@@ -43,8 +43,10 @@ The state transitioning model does all the necessary work to work out a valid ne
 3) Create a new state object if the recipient is \0*32
 4) Value transfer
 == If contract creation ==
-  4a) Attempt to run transaction data
-  4b) If valid, use result as code for the new state object
+
+	4a) Attempt to run transaction data
+	4b) If valid, use result as code for the new state object
+
 == end ==
 5) Run Script section
 6) Derive new state root
@@ -315,13 +317,13 @@ func (st *StateTransition) preCheck() error {
 // TransitionDb will transition the state by applying the current message and
 // returning the evm execution result with following fields.
 //
-// - used gas:
-//      total gas used (including gas being refunded)
-// - returndata:
-//      the returned data from evm
-// - concrete execution error:
-//      various **EVM** error which aborts the execution,
-//      e.g. ErrOutOfGas, ErrExecutionReverted
+//   - used gas:
+//     total gas used (including gas being refunded)
+//   - returndata:
+//     the returned data from evm
+//   - concrete execution error:
+//     various **EVM** error which aborts the execution,
+//     e.g. ErrOutOfGas, ErrExecutionReverted
 //
 // However if any consensus issue encountered, return the error directly with
 // nil evm execution result.
@@ -340,16 +342,16 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 	if err := st.preCheck(); err != nil {
 		return nil, err
 	}
-	msg := st.msg
-	sender := vm.AccountRef(msg.From())
-	homestead := st.evm.ChainConfig().IsHomestead(st.evm.Context.BlockNumber)
-	istanbul := st.evm.ChainConfig().IsIstanbul(st.evm.Context.BlockNumber)
-	shanghai := st.evm.ChainConfig().IsShanghai(st.evm.Context.BlockNumber)
-	london := st.evm.ChainConfig().IsLondon(st.evm.Context.BlockNumber)
-	contractCreation := msg.To() == nil
+
+	var (
+		msg              = st.msg
+		sender           = vm.AccountRef(msg.From())
+		rules            = st.evm.ChainConfig().Rules(st.evm.Context.BlockNumber)
+		contractCreation = msg.To() == nil
+	)
 
 	// Check clauses 4-5, subtract intrinsic gas if everything is correct
-	gas, err := IntrinsicGas(st.data, st.msg.AccessList(), contractCreation, homestead, istanbul, shanghai)
+	gas, err := IntrinsicGas(st.data, st.msg.AccessList(), contractCreation, rules.IsHomestead, rules.IsIstanbul, rules.IsShanghai)
 	if err != nil {
 		return nil, err
 	}
@@ -363,8 +365,6 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 		return nil, fmt.Errorf("%w: address %v", ErrInsufficientFundsForTransfer, msg.From().Hex())
 	}
 
-	rules := st.evm.ChainConfig().Rules(st.evm.Context.BlockNumber)
-
 	// Check whether the init code size has been exceeded.
 	if rules.IsShanghai && contractCreation && len(st.data) > params.MaxInitCodeSize {
 		return nil, fmt.Errorf("%w: code size %v limit %v", ErrMaxInitCodeSizeExceeded, len(st.data), params.MaxInitCodeSize)
@@ -397,15 +397,15 @@ func (st *StateTransition) TransitionDb() (*ExecutionResult, error) {
 		}, nil
 	}
 
-	if !london {
+	if !rules.IsLondon {
 		// Before EIP-3529: refunds were capped to gasUsed / 2
 		st.refundGas(params.RefundQuotient)
 	} else {
 		// After EIP-3529: refunds are capped to gasUsed / 5
 		st.refundGas(params.RefundQuotientEIP3529)
 	}
 	effectiveTip := st.gasPrice
-	if london {
+	if rules.IsLondon {
 		if st.evm.Context.BaseFee != nil {
 			effectiveTip = cmath.BigMin(st.gasTipCap, new(big.Int).Sub(st.gasFeeCap, st.evm.Context.BaseFee))
 		} else {