diff --git a/ast/visitor.go b/ast/visitor.go
index 287a7558..90bc9f1d 100644
--- a/ast/visitor.go
+++ b/ast/visitor.go
@@ -7,6 +7,9 @@ type Visitor interface {
 }
 
 func Walk(node *Node, v Visitor) {
+	if *node == nil {
+		return
+	}
 	switch n := (*node).(type) {
 	case *NilNode:
 	case *IdentifierNode:
diff --git a/checker/checker.go b/checker/checker.go
index 5e20e5e8..a2c86c20 100644
--- a/checker/checker.go
+++ b/checker/checker.go
@@ -18,7 +18,7 @@ import (
 func ParseCheck(input string, config *conf.Config) (*parser.Tree, error) {
 	tree, err := parser.ParseWithConfig(input, config)
 	if err != nil {
-		return nil, err
+		return tree, err
 	}
 
 	if len(config.Visitors) > 0 {
diff --git a/parser/parser.go b/parser/parser.go
index fd1b3c04..77b2a700 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -84,14 +84,16 @@ func ParseWithConfig(input string, config *conf.Config) (*Tree, error) {
 		p.error("unexpected token %v", p.current)
 	}
 
+	tree := &Tree{
+		Node:   node,
+		Source: source,
+	}
+
 	if p.err != nil {
-		return nil, p.err.Bind(source)
+		return tree, p.err.Bind(source)
 	}
 
-	return &Tree{
-		Node:   node,
-		Source: source,
-	}, nil
+	return tree, nil
 }
 
 func (p *parser) error(format string, args ...any) {