diff --git a/core/state/statedb.go b/core/state/statedb.go
index 7ad7ff7e6..c3534cabf 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -74,6 +74,15 @@ func (m *mutation) isDelete() bool {
 	return m.typ == deletion
 }
 
+type arbFiltered int
+
+const (
+	txFiltered arbFiltered = 1 + iota
+	blockFiltered
+)
+
+var ErrArbTxFilter error = errors.New("internal error")
+
 // StateDB structs within the ethereum protocol are used to store anything
 // within the merkle trie. StateDBs take care of caching and storing
 // nested states. It's the general query interface to retrieve:
@@ -87,7 +96,7 @@ func (m *mutation) isDelete() bool {
 // commit states.
 type StateDB struct {
 	arbExtraData *ArbitrumExtraData // must be a pointer - can't be a part of StateDB allocation, otherwise its finalizer might not get called
-	arbTxFilter  int
+	arbTxFilter  arbFiltered
 
 	db         Database
 	prefetcher *triePrefetcher
@@ -223,15 +232,15 @@ func New(root common.Hash, db Database, snaps *snapshot.Tree) (*StateDB, error)
 
 func (s *StateDB) FilterTx(withBlock bool) {
 	if s.arbTxFilter == 0 {
-		s.arbTxFilter = 1
+		s.arbTxFilter = txFiltered
 		if withBlock {
-			s.arbTxFilter = 2
+			s.arbTxFilter = blockFiltered
 		}
 	}
 }
 
 func (s *StateDB) IsTxInvalid() bool {
-	return s.arbTxFilter == 1
+	return s.arbTxFilter == txFiltered
 }
 
 // SetLogger sets the logger for account update hooks.
@@ -850,7 +859,7 @@ func (s *StateDB) RevertToSnapshot(revid int) {
 	revision := s.validRevisions[idx]
 	snapshot := revision.journalIndex
 	s.arbExtraData.unexpectedBalanceDelta = new(big.Int).Set(revision.unexpectedBalanceDelta)
-	if s.arbTxFilter == 1 {
+	if s.arbTxFilter == txFiltered {
 		s.arbTxFilter = 0
 	}
 
@@ -1238,8 +1247,8 @@ func (s *StateDB) GetTrie() Trie {
 // The associated block number of the state transition is also provided
 // for more chain context.
 func (s *StateDB) Commit(block uint64, deleteEmptyObjects bool) (common.Hash, error) {
-	if s.arbTxFilter == 2 {
-		return common.Hash{}, errors.New("internal error")
+	if s.arbTxFilter == blockFiltered {
+		return common.Hash{}, ErrArbTxFilter
 	}
 	// Short circuit in case any database failure occurred earlier.
 	if s.dbErr != nil {