From 2958714ec69032790518a7d74e1006540a5b163a Mon Sep 17 00:00:00 2001
From: Liang-Chi Hsieh <viirya@gmail.com>
Date: Sat, 30 Dec 2023 16:49:51 -0800
Subject: [PATCH] Fix clippy

---
 datafusion/expr/src/tree_node/expr.rs     | 18 +++++++++---------
 datafusion/physical-expr/src/utils/mod.rs |  2 +-
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/datafusion/expr/src/tree_node/expr.rs b/datafusion/expr/src/tree_node/expr.rs
index 3a12a2cfb8b5..56388be58b8a 100644
--- a/datafusion/expr/src/tree_node/expr.rs
+++ b/datafusion/expr/src/tree_node/expr.rs
@@ -61,10 +61,10 @@ impl TreeNode for Expr {
                 }
             }
             Expr::GroupingSet(GroupingSet::Rollup(exprs))
-            | Expr::GroupingSet(GroupingSet::Cube(exprs)) => exprs.into_iter().map(Cow::Borrowed).collect(),
-            Expr::ScalarFunction(ScalarFunction { args, .. }) => args.into_iter().map(Cow::Borrowed).collect(),
+            | Expr::GroupingSet(GroupingSet::Cube(exprs)) => exprs.iter().map(Cow::Borrowed).collect(),
+            Expr::ScalarFunction(ScalarFunction { args, .. }) => args.iter().map(Cow::Borrowed).collect(),
             Expr::GroupingSet(GroupingSet::GroupingSets(lists_of_exprs)) => {
-                lists_of_exprs.into_iter().flatten().map(Cow::Borrowed).collect()
+                lists_of_exprs.iter().flatten().map(Cow::Borrowed).collect()
             }
             Expr::Column(_)
             // Treat OuterReferenceColumn as a leaf expression
@@ -109,13 +109,13 @@ impl TreeNode for Expr {
                 order_by,
                 ..
             }) => {
-                let mut expr_vec: Vec<_> = args.into_iter().map(Cow::Borrowed).collect();
+                let mut expr_vec: Vec<_> = args.iter().map(Cow::Borrowed).collect();
 
                 if let Some(f) = filter {
                     expr_vec.push(Cow::Borrowed(f));
                 }
                 if let Some(o) = order_by {
-                    expr_vec.extend(o.into_iter().map(Cow::Borrowed).collect::<Vec<_>>());
+                    expr_vec.extend(o.iter().map(Cow::Borrowed).collect::<Vec<_>>());
                 }
 
                 expr_vec
@@ -126,14 +126,14 @@ impl TreeNode for Expr {
                 order_by,
                 ..
             }) => {
-                let mut expr_vec: Vec<_> = args.into_iter().map(Cow::Borrowed).collect();
-                expr_vec.extend(partition_by.into_iter().map(Cow::Borrowed).collect::<Vec<_>>());
-                expr_vec.extend(order_by.into_iter().map(Cow::Borrowed).collect::<Vec<_>>());
+                let mut expr_vec: Vec<_> = args.iter().map(Cow::Borrowed).collect();
+                expr_vec.extend(partition_by.iter().map(Cow::Borrowed).collect::<Vec<_>>());
+                expr_vec.extend(order_by.iter().map(Cow::Borrowed).collect::<Vec<_>>());
                 expr_vec
             }
             Expr::InList(InList { expr, list, .. }) => {
                 let mut expr_vec = vec![Cow::Borrowed(expr.as_ref())];
-                expr_vec.extend(list.into_iter().map(Cow::Borrowed).collect::<Vec<_>>());
+                expr_vec.extend(list.iter().map(Cow::Borrowed).collect::<Vec<_>>());
                 expr_vec
             }
         }
diff --git a/datafusion/physical-expr/src/utils/mod.rs b/datafusion/physical-expr/src/utils/mod.rs
index 808833b65946..64a62dc7820d 100644
--- a/datafusion/physical-expr/src/utils/mod.rs
+++ b/datafusion/physical-expr/src/utils/mod.rs
@@ -155,7 +155,7 @@ impl<T> ExprTreeNode<T> {
 
 impl<T: Clone> TreeNode for ExprTreeNode<T> {
     fn children_nodes(&self) -> Vec<Cow<Self>> {
-        self.children().into_iter().map(Cow::Borrowed).collect()
+        self.children().iter().map(Cow::Borrowed).collect()
     }
 
     fn map_children<F>(mut self, transform: F) -> Result<Self>