diff --git a/pkg/expr/mongo.go b/pkg/expr/mongo.go
index 6bd299417767024ec1d0befcce641c6f8241de9c..45d450a9e2301442e1adcc308c7ba33771f14f82 100644
--- a/pkg/expr/mongo.go
+++ b/pkg/expr/mongo.go
@@ -323,7 +323,7 @@ func (c *compiler) BinaryNode(node *ast.BinaryNode) interface{} {
 }
 
 func (c *compiler) ChainNode(node *ast.ChainNode) string {
-	panic(fmt.Sprintf("unsupported chain node"))
+	panic("unsupported chain node")
 }
 
 func (c *compiler) MemberNode(node *ast.MemberNode) string {