diff --git a/src/frontend/src/binder/bind_context.rs b/src/frontend/src/binder/bind_context.rs
index 003232b209e58..cb81b445f96e0 100644
--- a/src/frontend/src/binder/bind_context.rs
+++ b/src/frontend/src/binder/bind_context.rs
@@ -104,7 +104,7 @@ pub struct BindContext {
     pub clause: Option<Clause>,
     // The `BindContext`'s data on its column groups
     pub column_group_context: ColumnGroupContext,
-    /// Map the cte's name to its `Relation::Subquery`.
+    /// Map the cte's name to its binding state.
     /// The `ShareId` of the value is used to help the planner identify the share plan.
     pub cte_to_relation: HashMap<String, Rc<RefCell<(ShareId, BindingCteState, TableAlias)>>>,
     /// Current lambda functions's arguments
diff --git a/src/frontend/src/binder/query.rs b/src/frontend/src/binder/query.rs
index 8a45550b056f5..c83d70cd9cf18 100644
--- a/src/frontend/src/binder/query.rs
+++ b/src/frontend/src/binder/query.rs
@@ -296,7 +296,7 @@ impl Binder {
                     fetch,
                 } = query;
                 fn should_be_empty<T>(v: Option<T>, clause: &str) -> Result<()> {
-                    if !v.is_none() {
+                    if v.is_some() {
                         return Err(ErrorCode::BindError(format!(
                             "`{clause}` is not supported in recursive CTE"
                         ))
@@ -316,16 +316,16 @@ impl Binder {
                     right,
                 } = body
                 else {
-                    return Err(ErrorCode::BindError(format!(
-                        "`UNION` is required in recursive CTE"
-                    ))
+                    return Err(ErrorCode::BindError(
+                        "`UNION` is required in recursive CTE".to_string(),
+                    )
                     .into());
                 };
 
                 if !all {
-                    return Err(ErrorCode::BindError(format!(
-                        "only `UNION ALL` is supported in recursive CTE now"
-                    ))
+                    return Err(ErrorCode::BindError(
+                        "only `UNION ALL` is supported in recursive CTE now".to_string(),
+                    )
                     .into());
                 }
 
diff --git a/src/frontend/src/binder/relation/mod.rs b/src/frontend/src/binder/relation/mod.rs
index de76d4e59d7b9..a70323add1322 100644
--- a/src/frontend/src/binder/relation/mod.rs
+++ b/src/frontend/src/binder/relation/mod.rs
@@ -362,7 +362,7 @@ impl Binder {
 
             match cte_state {
                 BindingCteState::Init => {
-                    Err(ErrorCode::BindError(format!("Base term of recursive CTE not found, consider write it to left side of the `UNION` operator")).into())
+                    Err(ErrorCode::BindError("Base term of recursive CTE not found, consider write it to left side of the `UNION` operator".to_string()).into())
                 }
                 BindingCteState::BaseResolved { schema } => {
                     self.bind_table_to_context(
diff --git a/src/frontend/src/expr/mod.rs b/src/frontend/src/expr/mod.rs
index 81fe3b77615cd..e6b2c0d382b90 100644
--- a/src/frontend/src/expr/mod.rs
+++ b/src/frontend/src/expr/mod.rs
@@ -483,9 +483,7 @@ impl ExprImpl {
                         self.visit_bound_set_expr(left);
                         self.visit_bound_set_expr(right);
                     }
-                    BoundSetExpr::RecursiveUnion {
-                        base, recursive,
-                    } => {
+                    BoundSetExpr::RecursiveUnion { base, recursive } => {
                         self.visit_bound_set_expr(base);
                         self.visit_bound_set_expr(recursive);
                     }