diff --git a/optd-adaptive-demo/src/bin/optd-adaptive-three-join.rs b/optd-adaptive-demo/src/bin/optd-adaptive-three-join.rs
index 3217b890..9d17ba7d 100644
--- a/optd-adaptive-demo/src/bin/optd-adaptive-three-join.rs
+++ b/optd-adaptive-demo/src/bin/optd-adaptive-three-join.rs
@@ -84,7 +84,7 @@ async fn main() -> Result<()> {
     )
     .await;
 
-    let mut data_progress = vec![5; 3];
+    let mut data_progress = [5; 3];
     let mut iter = 0;
 
     fn do_insert(table: usize, begin: usize, end: usize, repeat: usize) -> String {
diff --git a/optd-core/src/cascades/memo.rs b/optd-core/src/cascades/memo.rs
index 44289589..3f406f42 100644
--- a/optd-core/src/cascades/memo.rs
+++ b/optd-core/src/cascades/memo.rs
@@ -167,7 +167,7 @@ impl<T: RelNodeTyp> Memo<T> {
             unreachable!("not found {}", memo_node)
         };
         let group_id = self.get_group_id_of_expr_id(expr_id);
-        return (group_id, expr_id);
+        (group_id, expr_id)
     }
 
     fn infer_properties(
diff --git a/optd-core/src/cascades/optimizer.rs b/optd-core/src/cascades/optimizer.rs
index 6cee8223..c3871cdd 100644
--- a/optd-core/src/cascades/optimizer.rs
+++ b/optd-core/src/cascades/optimizer.rs
@@ -214,9 +214,9 @@ impl<T: RelNodeTyp> CascadesOptimizer<T> {
         group_id: GroupId,
         mut on_produce: impl FnMut(RelNodeRef<T>, GroupId) -> RelNodeRef<T>,
     ) -> Result<RelNodeRef<T>> {
-        Ok(self
+        self
             .memo
-            .get_best_group_binding(group_id, &mut on_produce)?)
+            .get_best_group_binding(group_id, &mut on_produce)
     }
 
     fn fire_optimize_tasks(&mut self, group_id: GroupId) -> Result<()> {
diff --git a/optd-core/src/cascades/tasks/optimize_inputs.rs b/optd-core/src/cascades/tasks/optimize_inputs.rs
index fa260db5..2a3368f6 100644
--- a/optd-core/src/cascades/tasks/optimize_inputs.rs
+++ b/optd-core/src/cascades/tasks/optimize_inputs.rs
@@ -153,7 +153,7 @@ impl<T: RelNodeTyp> Task<T> for OptimizeInputsTask {
             };
             if self.should_terminate(
                 cost.sum(
-                    &cost.compute_cost(&expr.typ, &expr.data, &input_cost, Some(context.clone())),
+                    &cost.compute_cost(&expr.typ, &expr.data, &input_cost, Some(context)),
                     &input_cost,
                 )
                 .0[0],
@@ -177,7 +177,7 @@ impl<T: RelNodeTyp> Task<T> for OptimizeInputsTask {
                                     &expr.typ,
                                     &expr.data,
                                     &input_cost,
-                                    Some(context.clone()),
+                                    Some(context),
                                 ),
                                 &input_cost,
                             )
@@ -248,7 +248,7 @@ impl<T: RelNodeTyp> Task<T> for OptimizeInputsTask {
                             &expr.typ,
                             &expr.data,
                             &input_cost,
-                            Some(context.clone()),
+                            Some(context),
                         ),
                         &input_cost,
                     ),
diff --git a/optd-core/src/heuristics/optimizer.rs b/optd-core/src/heuristics/optimizer.rs
index 7886f5ae..4a081a0d 100644
--- a/optd-core/src/heuristics/optimizer.rs
+++ b/optd-core/src/heuristics/optimizer.rs
@@ -51,7 +51,7 @@ fn match_node<T: RelNodeTyp>(
             RuleMatcher::PickMany { pick_to } => {
                 let res = pick.insert(
                     *pick_to,
-                    RelNode::new_list(node.children[idx..].to_vec()).into(),
+                    RelNode::new_list(node.children[idx..].to_vec()),
                 );
                 assert!(res.is_none(), "dup pick");
                 should_end = true;
@@ -124,7 +124,7 @@ impl<T: RelNodeTyp> HeuristicsOptimizer<T> {
         for rule in self.rules.as_ref() {
             let matcher = rule.matcher();
             if let Some(picks) = match_and_pick(matcher, root_rel.clone()) {
-                let mut results = rule.apply(&self, picks);
+                let mut results = rule.apply(self, picks);
                 assert_eq!(results.len(), 1);
                 root_rel = results.remove(0).into();
             }
diff --git a/optd-datafusion-bridge/src/from_optd.rs b/optd-datafusion-bridge/src/from_optd.rs
index eb259496..1feb614c 100644
--- a/optd-datafusion-bridge/src/from_optd.rs
+++ b/optd-datafusion-bridge/src/from_optd.rs
@@ -49,7 +49,7 @@ fn from_optd_schema(optd_schema: &OptdSchema) -> Schema {
         .0
         .iter()
         .enumerate()
-        .map(|(i, typ)| Field::new(&format!("c{}", i), match_type(typ), false))
+        .map(|(i, typ)| Field::new(format!("c{}", i), match_type(typ), false))
         .collect();
     Schema::new(fields)
 }
@@ -108,7 +108,7 @@ impl OptdPlanContext<'_> {
             false,
             &args,
             &[],
-            &context,
+            context,
             "<agg_func>",
         )?)
     }
diff --git a/optd-datafusion-bridge/src/into_optd.rs b/optd-datafusion-bridge/src/into_optd.rs
index 1b0b6f80..2de6c0ce 100644
--- a/optd-datafusion-bridge/src/into_optd.rs
+++ b/optd-datafusion-bridge/src/into_optd.rs
@@ -72,7 +72,7 @@ impl OptdPlanContext<'_> {
                 }
                 ScalarValue::Int64(x) => {
                     let x = x.as_ref().unwrap();
-                    Ok(ConstantExpr::int(*x as i64).into_expr())
+                    Ok(ConstantExpr::int(*x).into_expr())
                 }
                 ScalarValue::Date32(x) => {
                     let x = x.as_ref().unwrap();
@@ -97,8 +97,8 @@ impl OptdPlanContext<'_> {
                 let when_then_expr = &x.when_then_expr;
                 assert_eq!(when_then_expr.len(), 1);
                 let (when_expr, then_expr) = &when_then_expr[0];
-                let when_expr = self.into_optd_expr(&when_expr, context)?;
-                let then_expr = self.into_optd_expr(&then_expr, context)?;
+                let when_expr = self.into_optd_expr(when_expr, context)?;
+                let then_expr = self.into_optd_expr(then_expr, context)?;
                 let else_expr = self.into_optd_expr(x.else_expr.as_ref().unwrap(), context)?;
                 assert!(x.expr.is_none());
                 Ok(FuncExpr::new(
@@ -226,20 +226,20 @@ impl OptdPlanContext<'_> {
 
             match node.filter {
                 Some(DFExpr::Literal(ScalarValue::Boolean(Some(val)))) => {
-                    return Ok(LogicalJoin::new(
+                    Ok(LogicalJoin::new(
                         left,
                         right,
                         ConstantExpr::bool(val).into_expr(),
                         join_type,
-                    ));
+                    ))
                 }
                 None => {
-                    return Ok(LogicalJoin::new(
+                    Ok(LogicalJoin::new(
                         left,
                         right,
                         ConstantExpr::bool(true).into_expr(),
                         join_type,
-                    ));
+                    ))
                 }
                 _ => bail!("unsupported join filter: {:?}", node.filter),
             }
diff --git a/optd-datafusion-repr/src/plan_nodes.rs b/optd-datafusion-repr/src/plan_nodes.rs
index 37860d39..f47fe342 100644
--- a/optd-datafusion-repr/src/plan_nodes.rs
+++ b/optd-datafusion-repr/src/plan_nodes.rs
@@ -207,7 +207,7 @@ impl PlanNode {
     }
 
     pub fn from_group(rel_node: OptRelNodeRef) -> Self {
-        return Self(rel_node);
+        Self(rel_node)
     }
 }
 
diff --git a/optd-datafusion-repr/src/rules/joins.rs b/optd-datafusion-repr/src/rules/joins.rs
index 09591b62..a0314140 100644
--- a/optd-datafusion-repr/src/rules/joins.rs
+++ b/optd-datafusion-repr/src/rules/joins.rs
@@ -342,7 +342,8 @@ fn apply_projection_pull_up_join(
                 .into_rel_node(),
             );
         }
-        let expr = Expr::from_rel_node(
+        
+        Expr::from_rel_node(
             RelNode {
                 typ: expr.typ.clone(),
                 children,
@@ -350,8 +351,7 @@ fn apply_projection_pull_up_join(
             }
             .into(),
         )
-        .unwrap();
-        expr
+        .unwrap()
     }
 
     let left = Arc::new(left.clone());
diff --git a/optd-sqlplannertest/src/bin/planner_test_apply.rs b/optd-sqlplannertest/src/bin/planner_test_apply.rs
index f1436d70..50608bf4 100644
--- a/optd-sqlplannertest/src/bin/planner_test_apply.rs
+++ b/optd-sqlplannertest/src/bin/planner_test_apply.rs
@@ -6,7 +6,7 @@ use anyhow::Result;
 async fn main() -> Result<()> {
     sqlplannertest::planner_test_apply(
         Path::new(env!("CARGO_MANIFEST_DIR")).join("tests"),
-        || async { Ok(optd_sqlplannertest::DatafusionDb::new().await?) },
+        || async { optd_sqlplannertest::DatafusionDb::new().await },
     )
     .await?;
     Ok(())
diff --git a/optd-sqlplannertest/src/lib.rs b/optd-sqlplannertest/src/lib.rs
index 470c6625..a7cbff9d 100644
--- a/optd-sqlplannertest/src/lib.rs
+++ b/optd-sqlplannertest/src/lib.rs
@@ -108,7 +108,7 @@ impl DatafusionDb {
     /// Executes the `execute` task.
     async fn task_execute(&mut self, r: &mut String, sql: &str, with_logical: bool) -> Result<()> {
         use std::fmt::Write;
-        let result = self.execute(&sql, with_logical).await?;
+        let result = self.execute(sql, with_logical).await?;
         writeln!(r, "{}", result.into_iter().map(|x| x.join(" ")).join("\n"))?;
         writeln!(r)?;
         Ok(())
@@ -132,7 +132,7 @@ impl DatafusionDb {
         } else {
             "explain:".len()
         };
-        for subtask in task[subtask_start_pos..].split(",") {
+        for subtask in task[subtask_start_pos..].split(',') {
             let subtask = subtask.trim();
             if subtask == "logical_datafusion" {
                 writeln!(
diff --git a/optd-sqlplannertest/tests/planner_test.rs b/optd-sqlplannertest/tests/planner_test.rs
index 806b6f0d..f870ce7c 100644
--- a/optd-sqlplannertest/tests/planner_test.rs
+++ b/optd-sqlplannertest/tests/planner_test.rs
@@ -5,7 +5,7 @@ use anyhow::Result;
 fn main() -> Result<()> {
     sqlplannertest::planner_test_runner(
         Path::new(env!("CARGO_MANIFEST_DIR")).join("tests"),
-        || async { Ok(optd_sqlplannertest::DatafusionDb::new().await?) },
+        || async { optd_sqlplannertest::DatafusionDb::new().await },
     )?;
     Ok(())
 }