new clippy fixes

polars/polars-core/src/datatypes.rs

@@ -549,17 +549,11 @@ impl Field {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Hash)]
+#[derive(Clone, Debug, PartialEq, Hash, Default)]
 pub struct Schema {
     fields: Vec<Field>,
 }
 
-impl Default for Schema {
-    fn default() -> Self {
-        Schema { fields: vec![] }
-    }
-}
-
 impl Schema {
     pub fn rename<I, J, T, S>(&self, old_names: I, new_names: J) -> Result<Schema>
     where

polars/polars-core/src/vector_hasher.rs

@@ -297,6 +297,7 @@ impl AsU64 for [u8; 13] {
     }
 }
 
+#[derive(Default)]
 pub struct IdHasher {
     hash: u64,
 }
@@ -331,12 +332,6 @@ impl Hasher for IdHasher {
     }
 }
 
-impl Default for IdHasher {
-    fn default() -> Self {
-        IdHasher { hash: 0 }
-    }
-}
-
 pub type IdBuildHasher = BuildHasherDefault<IdHasher>;
 
 #[derive(Debug)]

polars/polars-lazy/src/frame.rs

@@ -179,21 +179,12 @@ impl IntoLazy for DataFrame {
 /// Lazy abstraction over an eager `DataFrame`.
 /// It really is an abstraction over a logical plan. The methods of this struct will incrementally
 /// modify a logical plan until output is requested (via [collect](crate::frame::LazyFrame::collect))
-#[derive(Clone)]
+#[derive(Clone, Default)]
 pub struct LazyFrame {
     pub(crate) logical_plan: LogicalPlan,
     pub(crate) opt_state: OptState,
 }
 
-impl Default for LazyFrame {
-    fn default() -> Self {
-        LazyFrame {
-            logical_plan: LogicalPlan::default(),
-            opt_state: Default::default(),
-        }
-    }
-}
-
 impl From<LogicalPlan> for LazyFrame {
     fn from(plan: LogicalPlan) -> Self {
         Self {

polars/polars-lazy/src/logical_plan/optimizer/predicate_pushdown/mod.rs

@@ -8,14 +8,9 @@ use polars_core::datatypes::PlHashMap;
 use polars_core::prelude::*;
 use utils::*;
 
+#[derive(Default)]
 pub(crate) struct PredicatePushDown {}
 
-impl Default for PredicatePushDown {
-    fn default() -> Self {
-        Self {}
-    }
-}
-
 impl PredicatePushDown {
     fn apply_predicate(
         &self,

polars/polars-lazy/src/physical_plan/executors/scan.rs

@@ -154,6 +154,7 @@ impl Executor for CsvExec {
             .with_predicate(predicate)
             .with_aggregate(aggregate)
             .with_encoding(CsvEncoding::LossyUtf8)
+            .with_comment_char(self.options.comment_char)
             .finish()?;
 
         if self.options.cache {

polars/polars-lazy/src/physical_plan/planner.rs

@@ -59,12 +59,8 @@ fn aggregate_expr_to_scan_agg(
         .collect()
 }
 
+#[derive(Default)]
 pub struct DefaultPlanner {}
-impl Default for DefaultPlanner {
-    fn default() -> Self {
-        Self {}
-    }
-}
 
 impl PhysicalPlanner for DefaultPlanner {
     fn create_physical_plan(