token AST tree does not need mutex

gherkin/ast.go

@@ -1,10 +1,6 @@
 package gherkin
 
-import (
-	"sync"
-
-	"github.com/l3pp4rd/go-behat/gherkin/lexer"
-)
+import "github.com/l3pp4rd/go-behat/gherkin/lexer"
 
 type item struct {
 	next, prev *item
@@ -13,17 +9,13 @@ type item struct {
 
 type AST struct {
 	head, tail *item
-	mut        *sync.Mutex
 }
 
 func newAST() *AST {
-	return &AST{mut: &sync.Mutex{}}
+	return &AST{}
 }
 
 func (l *AST) addTail(t *lexer.Token) *item {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-
 	it := &item{next: nil, prev: l.tail, value: t}
 	if l.head == nil {
 		l.head = it
@@ -35,9 +27,6 @@ func (l *AST) addTail(t *lexer.Token) *item {
 }
 
 func (l *AST) addBefore(t *lexer.Token, i *item) *item {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-
 	it := &item{next: i, prev: i.prev, value: t}
 	i.prev = it
 	if it.prev == nil {
@@ -47,9 +36,6 @@ func (l *AST) addBefore(t *lexer.Token, i *item) *item {
 }
 
 func (l *AST) addAfter(t *lexer.Token, i *item) *item {
-	l.mut.Lock()
-	defer l.mut.Unlock()
-
 	it := &item{next: i.next, prev: i, value: t}
 	i.next = it
 	if it.next == nil {