4 files changed, 16 insertions, 39 deletions
diff --git a/compiler/dfa/dfa.go b/compiler/dfa/dfa.go
index c56af90..777bd24 100644
--- a/compiler/dfa/dfa.go
+++ b/compiler/dfa/dfa.go
@@ -47,7 +47,7 @@ type DFA struct {
 	TransitionTable      map[string][256]string
 }
 
-func GenDFA(root byteTree, symTab *symbolTable) *DFA {	
+func GenDFA(root byteTree, symTab *symbolTable) *DFA {
 	initialState := root.first()
 	initialStateHash := initialState.hash()
 	stateMap := map[string]*symbolPositionSet{
diff --git a/compiler/dfa/symbol_position.go b/compiler/dfa/symbol_position.go
index 10d5a1e..f154251 100644
--- a/compiler/dfa/symbol_position.go
+++ b/compiler/dfa/symbol_position.go
@@ -38,10 +38,7 @@ func (p symbolPosition) String() string {
 }
 
 func (p symbolPosition) isEndMark() bool {
-	if uint16(p)&symbolPositionMaskEndMark > 1 {
-		return true
-	}
-	return false
+	return uint16(p)&symbolPositionMaskEndMark > 1
 }
 
 func (p symbolPosition) describe() (uint16, bool) {
@@ -102,19 +99,6 @@ func (s *symbolPositionSet) merge(t *symbolPositionSet) *symbolPositionSet {
 	return s
 }
 
-func (s *symbolPositionSet) intersect(set *symbolPositionSet) *symbolPositionSet {
-	in := newSymbolPositionSet()
-	for _, p1 := range s.s {
-		for _, p2 := range set.s {
-			if p1 != p2 {
-				continue
-			}
-			in.add(p1)
-		}
-	}
-	return in
-}
-
 func (s *symbolPositionSet) hash() string {
 	if len(s.s) <= 0 {
 		return ""
@@ -171,9 +155,9 @@ func sortSymbolPositions(ps []symbolPosition, left, right int) {
 			p1, p2 = p2, p1
 		}
 		if p2 > p3 {
-			p2, p3 = p3, p2
+			p2 = p3
 			if p1 > p2 {
-				p1, p2 = p2, p1
+				p2 = p1
 			}
 		}
 		pivot = p2
diff --git a/compiler/dfa/tree.go b/compiler/dfa/tree.go
index a3442f8..bd93a26 100644
--- a/compiler/dfa/tree.go
+++ b/compiler/dfa/tree.go
@@ -153,7 +153,7 @@ func newConcatNode(left, right byteTree) *concatNode {
 }
 
 func (n *concatNode) String() string {
-	return fmt.Sprintf("concat")
+	return "concat"
 }
 
 func (n *concatNode) children() (byteTree, byteTree) {
@@ -207,7 +207,7 @@ func newAltNode(left, right byteTree) *altNode {
 }
 
 func (n *altNode) String() string {
-	return fmt.Sprintf("alt")
+	return "alt"
 }
 
 func (n *altNode) children() (byteTree, byteTree) {
@@ -255,7 +255,7 @@ func newRepeatNode(left byteTree) *repeatNode {
 }
 
 func (n *repeatNode) String() string {
-	return fmt.Sprintf("repeat")
+	return "repeat"
 }
 
 func (n *repeatNode) children() (byteTree, byteTree) {
@@ -288,14 +288,6 @@ func (n *repeatNode) clone() byteTree {
 	return newRepeatNode(n.left.clone())
 }
 
-func newRepeatOneOrMoreNode(left byteTree) *concatNode {
-	return newConcatNode(
-		left,
-		&repeatNode{
-			left: left.clone(),
-		})
-}
-
 type optionNode struct {
 	left      byteTree
 	firstMemo *symbolPositionSet
@@ -309,7 +301,7 @@ func newOptionNode(left byteTree) *optionNode {
 }
 
 func (n *optionNode) String() string {
-	return fmt.Sprintf("option")
+	return "option"
 }
 
 func (n *optionNode) children() (byteTree, byteTree) {
@@ -452,6 +444,7 @@ func oneOf(ts ...byteTree) byteTree {
 	return alt
 }
 
+//nolint:unused
 func printByteTree(w io.Writer, t byteTree, ruledLine string, childRuledLinePrefix string, withAttrs bool) {
 	if t == nil {
 		return
@@ -505,7 +498,10 @@ func ConvertCPTreeToByteTree(cpTrees map[spec.LexModeKindID]parser.CPTree) (byte
 		}
 		bt = oneOf(bt, concat(t, newEndMarkerNode(id)))
 	}
-	positionSymbols(bt, symbolPositionMin)
+	_, err := positionSymbols(bt, symbolPositionMin)
+	if err != nil {
+		return nil, nil, err
+	}
 
 	return bt, genSymbolTable(bt), nil
 }
diff --git a/compiler/dfa/tree_test.go b/compiler/dfa/tree_test.go
index e37a69c..1c1fd1d 100644
--- a/compiler/dfa/tree_test.go
+++ b/compiler/dfa/tree_test.go
@@ -128,12 +128,6 @@ func TestByteTree(t *testing.T) {
 	}
 }
 
-func newRangeSymbolNodeWithPos(from, to byte, pos symbolPosition) *symbolNode {
-	n := newRangeSymbolNode(from, to)
-	n.pos = pos
-	return n
-}
-
 func newSymbolNodeWithPos(v byte, pos symbolPosition) *symbolNode {
 	n := newSymbolNode(v)
 	n.pos = pos
@@ -172,6 +166,9 @@ func TestFollowAndSymbolTable(t *testing.T) {
 	bt, symTab, err := ConvertCPTreeToByteTree(map[spec.LexModeKindID]parser.CPTree{
 		spec.LexModeKindIDMin: cpt,
 	})
+	if err != nil {
+		t.Fatal(err)
+	}
 
 	{
 		followTab := genFollowTable(bt)