3 files changed, 7 insertions, 9 deletions
diff --git a/compiler/parser/lexer.go b/compiler/parser/lexer.go
index 01cebeb..3861825 100644
--- a/compiler/parser/lexer.go
+++ b/compiler/parser/lexer.go
@@ -416,7 +416,7 @@ func (l *lexer) nextInCodePoint(c rune) (*token, error) {
 				return nil, err
 			}
 			if eof {
-				l.restore()
+				err := l.restore()
 				if err != nil {
 					return nil, err
 				}
@@ -471,7 +471,7 @@ func (l *lexer) nextInCharProp(c rune) (*token, error) {
 				return nil, err
 			}
 			if eof {
-				l.restore()
+				err := l.restore()
 				if err != nil {
 					return nil, err
 				}
@@ -512,7 +512,7 @@ func (l *lexer) nextInFragment(c rune) (*token, error) {
 				return nil, err
 			}
 			if eof {
-				l.restore()
+				err := l.restore()
 				if err != nil {
 					return nil, err
 				}
diff --git a/compiler/parser/parser.go b/compiler/parser/parser.go
index fd85fab..3706525 100644
--- a/compiler/parser/parser.go
+++ b/compiler/parser/parser.go
@@ -446,10 +446,7 @@ func genAnyCharAST() CPTree {
 }
 
 func isValidOrder(from, to rune) bool {
-	if from <= to {
-		return true
-	}
-	return false
+	return from <= to
 }
 
 func genConcatNode(cs ...CPTree) CPTree {
diff --git a/compiler/parser/tree.go b/compiler/parser/tree.go
index b5fb723..04ba723 100644
--- a/compiler/parser/tree.go
+++ b/compiler/parser/tree.go
@@ -207,7 +207,7 @@ func newConcatNode(left, right CPTree) *concatNode {
 }
 
 func (n *concatNode) String() string {
-	return fmt.Sprintf("concat")
+	return "concat"
 }
 
 func (n *concatNode) Range() (rune, rune, bool) {
@@ -258,7 +258,7 @@ func newAltNode(left, right CPTree) *altNode {
 }
 
 func (n *altNode) String() string {
-	return fmt.Sprintf("alt")
+	return "alt"
 }
 
 func (n *altNode) Range() (rune, rune, bool) {
@@ -419,6 +419,7 @@ func (n *fragmentNode) clone() CPTree {
 	return newFragmentNode(n.kind, n.tree.clone())
 }
 
+//nolint:unused
 func printCPTree(w io.Writer, t CPTree, ruledLine string, childRuledLinePrefix string) {
 	if t == nil {
 		return