Fix up clippy for Rust 1.78

arrow-cast/src/parse.rs

@@ -435,11 +435,20 @@ impl Parser for Float64Type {
     }
 }
 
+/// This API is only stable since 1.70 so can't use it when current MSRV is lower
+#[inline(always)]
+pub fn is_some_and<T>(opt: Option<T>, f: impl FnOnce(T) -> bool) -> bool {
+    match opt {
+        None => false,
+        Some(x) => f(x),
+    }
+}
+
 macro_rules! parser_primitive {
     ($t:ty) => {
         impl Parser for $t {
             fn parse(string: &str) -> Option<Self::Native> {
-                if !string.as_bytes().last().is_some_and(|x| x.is_ascii_digit()) {
+                if !is_some_and(string.as_bytes().last(), |x| x.is_ascii_digit()) {
                     return None;
                 }
                 match atoi::FromRadix10SignedChecked::from_radix_10_signed_checked(

arrow-integration-testing/src/bin/arrow-json-integration-test.rs

@@ -40,7 +40,13 @@ struct Args {
     arrow: String,
     #[clap(short, long, help("Path to JSON file"))]
     json: String,
-    #[clap(value_enum, short, long, default_value_t = Mode::Validate, help="Mode of integration testing tool")]
+    #[clap(
+        value_enum,
+        short,
+        long,
+        default_value = "VALIDATE",
+        help = "Mode of integration testing tool"
+    )]
     mode: Mode,
     #[clap(short, long)]
     verbose: bool,

arrow-json/src/reader/serializer.rs

@@ -309,16 +309,16 @@ impl<'a, 'b> SerializeMap for ObjectSerializer<'a, 'b> {
     type Ok = ();
     type Error = SerializerError;
 
-    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
+    fn serialize_key<T>(&mut self, key: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: Serialize + ?Sized,
     {
         key.serialize(&mut *self.serializer)
     }
 
-    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_value<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: Serialize + ?Sized,
     {
         value.serialize(&mut *self.serializer)
     }
@@ -333,13 +333,9 @@ impl<'a, 'b> SerializeStruct for ObjectSerializer<'a, 'b> {
     type Ok = ();
     type Error = SerializerError;
 
-    fn serialize_field<T: ?Sized>(
-        &mut self,
-        key: &'static str,
-        value: &T,
-    ) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, key: &'static str, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: Serialize + ?Sized,
     {
         key.serialize(&mut *self.serializer)?;
         value.serialize(&mut *self.serializer)
@@ -376,9 +372,9 @@ impl<'a, 'b> SerializeSeq for ListSerializer<'a, 'b> {
     type Ok = ();
     type Error = SerializerError;
 
-    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: Serialize + ?Sized,
     {
         value.serialize(&mut *self.serializer)
     }
@@ -393,9 +389,9 @@ impl<'a, 'b> SerializeTuple for ListSerializer<'a, 'b> {
     type Ok = ();
     type Error = SerializerError;
 
-    fn serialize_element<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_element<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: Serialize + ?Sized,
     {
         value.serialize(&mut *self.serializer)
     }
@@ -410,9 +406,9 @@ impl<'a, 'b> SerializeTupleStruct for ListSerializer<'a, 'b> {
     type Ok = ();
     type Error = SerializerError;
 
-    fn serialize_field<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    fn serialize_field<T>(&mut self, value: &T) -> Result<(), Self::Error>
     where
-        T: Serialize,
+        T: Serialize + ?Sized,
     {
         value.serialize(&mut *self.serializer)
     }

arrow-json/src/writer/encoder.rs

@@ -155,12 +155,21 @@ struct StructArrayEncoder<'a> {
     explicit_nulls: bool,
 }
 
+/// This API is only stable since 1.70 so can't use it when current MSRV is lower
+#[inline(always)]
+pub fn is_some_and<T>(opt: Option<T>, f: impl FnOnce(T) -> bool) -> bool {
+    match opt {
+        None => false,
+        Some(x) => f(x),
+    }
+}
+
 impl<'a> Encoder for StructArrayEncoder<'a> {
     fn encode(&mut self, idx: usize, out: &mut Vec<u8>) {
         out.push(b'{');
         let mut is_first = true;
         for field_encoder in &mut self.encoders {
-            let is_null = field_encoder.nulls.as_ref().is_some_and(|n| n.is_null(idx));
+            let is_null = is_some_and(field_encoder.nulls.as_ref(), |n| n.is_null(idx));
             if is_null && !self.explicit_nulls {
                 continue;
             }
@@ -447,13 +456,13 @@ impl<'a> MapEncoder<'a> {
         let (values, value_nulls) = make_encoder_impl(values, options)?;
 
         // We sanity check nulls as these are currently not enforced by MapArray (#1697)
-        if key_nulls.is_some_and(|x| x.null_count() != 0) {
+        if is_some_and(key_nulls, |x| x.null_count() != 0) {
             return Err(ArrowError::InvalidArgumentError(
                 "Encountered nulls in MapArray keys".to_string(),
             ));
         }
 
-        if array.entries().nulls().is_some_and(|x| x.null_count() != 0) {
+        if is_some_and(array.entries().nulls(), |x| x.null_count() != 0) {
             return Err(ArrowError::InvalidArgumentError(
                 "Encountered nulls in MapArray entries".to_string(),
             ));
@@ -478,7 +487,7 @@ impl<'a> Encoder for MapEncoder<'a> {
 
         out.push(b'{');
         for idx in start..end {
-            let is_null = self.value_nulls.as_ref().is_some_and(|n| n.is_null(idx));
+            let is_null = is_some_and(self.value_nulls.as_ref(), |n| n.is_null(idx));
             if is_null && !self.explicit_nulls {
                 continue;
             }

arrow-select/src/take.rs

@@ -1401,9 +1401,9 @@ mod tests {
         );
     }
 
-    fn _test_take_string<'a, K: 'static>()
+    fn _test_take_string<'a, K>()
     where
-        K: Array + PartialEq + From<Vec<Option<&'a str>>>,
+        K: Array + PartialEq + From<Vec<Option<&'a str>>> + 'static,
     {
         let index = UInt32Array::from(vec![Some(3), None, Some(1), Some(3), Some(4)]);
 

arrow/src/util/string_writer.rs

@@ -63,6 +63,7 @@
 //! }
 //! ```
 
+use std::fmt::Formatter;
 use std::io::{Error, ErrorKind, Result, Write};
 
 #[derive(Debug)]
@@ -83,10 +84,9 @@ impl Default for StringWriter {
         Self::new()
     }
 }
-
-impl ToString for StringWriter {
-    fn to_string(&self) -> String {
-        self.data.clone()
+impl std::fmt::Display for StringWriter {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.data)
     }
 }
 

parquet/src/column/writer/mod.rs

@@ -1172,13 +1172,6 @@ fn compare_greater<T: ParquetValueType>(descr: &ColumnDescriptor, a: &T, b: &T)
 // https://github.com/apache/parquet-mr/blob/master/parquet-column/src/main/java/org/apache/parquet/column/values/factory/DefaultV1ValuesWriterFactory.java
 // https://github.com/apache/parquet-mr/blob/master/parquet-column/src/main/java/org/apache/parquet/column/values/factory/DefaultV2ValuesWriterFactory.java
 
-/// Trait to define default encoding for types, including whether or not the type
-/// supports dictionary encoding.
-trait EncodingWriteSupport {
-    /// Returns true if dictionary is supported for column writer, false otherwise.
-    fn has_dictionary_support(props: &WriterProperties) -> bool;
-}
-
 /// Returns encoding for a column when no other encoding is provided in writer properties.
 fn fallback_encoding(kind: Type, props: &WriterProperties) -> Encoding {
     match (kind, props.writer_version()) {

parquet/src/encodings/encoding/mod.rs

@@ -24,7 +24,7 @@ use crate::data_type::private::ParquetValueType;
 use crate::data_type::*;
 use crate::encodings::rle::RleEncoder;
 use crate::errors::{ParquetError, Result};
-use crate::util::bit_util::{self, num_required_bits, BitWriter};
+use crate::util::bit_util::{num_required_bits, BitWriter};
 
 use bytes::Bytes;
 pub use dict_encoder::DictEncoder;
@@ -47,12 +47,13 @@ pub trait Encoder<T: DataType>: Send {
     /// identified by `valid_bits`.
     ///
     /// Returns the number of non-null values encoded.
+    #[cfg(test)]
     fn put_spaced(&mut self, values: &[T::T], valid_bits: &[u8]) -> Result<usize> {
         let num_values = values.len();
         let mut buffer = Vec::with_capacity(num_values);
         // TODO: this is pretty inefficient. Revisit in future.
         for (i, item) in values.iter().enumerate().take(num_values) {
-            if bit_util::get_bit(valid_bits, i) {
+            if crate::util::bit_util::get_bit(valid_bits, i) {
                 buffer.push(item.clone());
             }
         }
@@ -727,6 +728,7 @@ mod tests {
     use crate::encodings::decoding::{get_decoder, Decoder, DictDecoder, PlainDecoder};
     use crate::schema::types::{ColumnDescPtr, ColumnDescriptor, ColumnPath, Type as SchemaType};
     use crate::util::test_common::rand_gen::{random_bytes, RandGen};
+    use crate::util::bit_util;
 
     const TEST_SET_SIZE: usize = 1024;
 

parquet/src/file/statistics.rs

@@ -271,8 +271,8 @@ pub fn to_thrift(stats: Option<&Statistics>) -> Option<TStatistics> {
 
     if stats.is_min_max_backwards_compatible() {
         // Copy to deprecated min, max values for compatibility with older readers
-        thrift_stats.min = min.clone();
-        thrift_stats.max = max.clone();
+        thrift_stats.min.clone_from(&min);
+        thrift_stats.max.clone_from(&max);
     }
 
     if !stats.is_min_max_deprecated() {