Remove a clone

Author: hareshkh

datafusion/substrait/src/logical_plan/consumer/rel/join_rel.rs

@@ -116,11 +116,11 @@ fn split_eq_and_noneq_join_predicate_with_nulls_equality(
         match (eq_keys.is_empty(), indistinct_keys.is_empty()) {
             // Mixed: use eq_keys as equijoin keys, demote indistinct keys to filter
             (false, false) => {
-                for (l, r) in &indistinct_keys {
+                for (l, r) in indistinct_keys {
                     accum_filters.push(Expr::BinaryExpr(BinaryExpr {
-                        left: Box::new(Expr::Column(l.clone())),
+                        left: Box::new(Expr::Column(l)),
                         op: Operator::IsNotDistinctFrom,
-                        right: Box::new(Expr::Column(r.clone())),
+                        right: Box::new(Expr::Column(r)),
                     }));
                 }
                 (eq_keys, NullEquality::NullEqualsNothing)