diff --git a/src/frontend/src/optimizer/mod.rs b/src/frontend/src/optimizer/mod.rs
index 16de0bacb5e1a..4d551f59587cf 100644
--- a/src/frontend/src/optimizer/mod.rs
+++ b/src/frontend/src/optimizer/mod.rs
@@ -1,5 +1,3 @@
-use std::assert_matches::assert_matches;
-use std::collections::{HashMap, HashSet};
 // Copyright 2024 RisingWave Labs
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -39,6 +37,9 @@ pub mod plan_expr_rewriter;
 mod plan_expr_visitor;
 mod rule;
 
+use std::assert_matches::assert_matches;
+use std::collections::{HashMap, HashSet};
+
 use fixedbitset::FixedBitSet;
 use itertools::Itertools as _;
 pub use logical_optimization::*;