From ccddaa83c989c23c9af819b2dc60c47dd0abe526 Mon Sep 17 00:00:00 2001
From: Liang-Chi Hsieh <viirya@gmail.com>
Date: Thu, 30 Jun 2022 20:40:13 -0700
Subject: [PATCH] Fix clippy (#1984)

---
 arrow/src/array/array_dictionary.rs     | 2 +-
 arrow/src/array/array_primitive.rs      | 2 +-
 arrow/src/array/array_string.rs         | 2 +-
 arrow/src/compute/kernels/arithmetic.rs | 4 +---
 arrow/src/util/display.rs               | 3 ++-
 parquet/src/encodings/decoding.rs       | 4 +---
 6 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/arrow/src/array/array_dictionary.rs b/arrow/src/array/array_dictionary.rs
index d0222ba9d47..d885a6bc0e5 100644
--- a/arrow/src/array/array_dictionary.rs
+++ b/arrow/src/array/array_dictionary.rs
@@ -114,7 +114,7 @@ pub struct DictionaryArray<K: ArrowPrimitiveType> {
     is_ordered: bool,
 }
 
-impl<'a, K: ArrowPrimitiveType> DictionaryArray<K> {
+impl<K: ArrowPrimitiveType> DictionaryArray<K> {
     /// Attempt to create a new DictionaryArray with a specified keys
     /// (indexes into the dictionary) and values (dictionary)
     /// array. Returns an error if there are any keys that are outside
diff --git a/arrow/src/array/array_primitive.rs b/arrow/src/array/array_primitive.rs
index 6f496562f89..427bda636ee 100644
--- a/arrow/src/array/array_primitive.rs
+++ b/arrow/src/array/array_primitive.rs
@@ -390,7 +390,7 @@ impl<T: ArrowPrimitiveType> From<&Option<<T as ArrowPrimitiveType>::Native>>
     }
 }
 
-impl<'a, T: ArrowPrimitiveType, Ptr: Into<NativeAdapter<T>>> FromIterator<Ptr>
+impl<T: ArrowPrimitiveType, Ptr: Into<NativeAdapter<T>>> FromIterator<Ptr>
     for PrimitiveArray<T>
 {
     fn from_iter<I: IntoIterator<Item = Ptr>>(iter: I) -> Self {
diff --git a/arrow/src/array/array_string.rs b/arrow/src/array/array_string.rs
index 9e09350f7e6..dba983b0180 100644
--- a/arrow/src/array/array_string.rs
+++ b/arrow/src/array/array_string.rs
@@ -211,7 +211,7 @@ where
     }
 }
 
-impl<'a, Ptr, OffsetSize: OffsetSizeTrait> FromIterator<Option<Ptr>>
+impl<Ptr, OffsetSize: OffsetSizeTrait> FromIterator<Option<Ptr>>
     for GenericStringArray<OffsetSize>
 where
     Ptr: AsRef<str>,
diff --git a/arrow/src/compute/kernels/arithmetic.rs b/arrow/src/compute/kernels/arithmetic.rs
index 248e8df2770..0189dade2ef 100644
--- a/arrow/src/compute/kernels/arithmetic.rs
+++ b/arrow/src/compute/kernels/arithmetic.rs
@@ -1071,9 +1071,7 @@ mod tests {
     fn test_primitive_array_add_mismatched_length() {
         let a = Int32Array::from(vec![5, 6, 7, 8, 9]);
         let b = Int32Array::from(vec![6, 7, 8]);
-        let e = add(&a, &b)
-            .err()
-            .expect("should have failed due to different lengths");
+        let e = add(&a, &b).expect_err("should have failed due to different lengths");
         assert_eq!(
             "ComputeError(\"Cannot perform math operation on arrays of different length\")",
             format!("{:?}", e)
diff --git a/arrow/src/util/display.rs b/arrow/src/util/display.rs
index 6da73e4cff6..220aa59ad40 100644
--- a/arrow/src/util/display.rs
+++ b/arrow/src/util/display.rs
@@ -19,6 +19,7 @@
 //! purposes. See the `pretty` crate for additional functions for
 //! record batch pretty printing.
 
+use std::fmt::Write;
 use std::sync::Arc;
 
 use crate::array::Array;
@@ -208,7 +209,7 @@ macro_rules! make_string_hex {
             let mut tmp = "".to_string();
 
             for character in array.value($row) {
-                tmp += &format!("{:02x}", character);
+                let _ = write!(tmp, "{:02x}", character);
             }
 
             tmp
diff --git a/parquet/src/encodings/decoding.rs b/parquet/src/encodings/decoding.rs
index 7c95d553234..b33514aaf62 100644
--- a/parquet/src/encodings/decoding.rs
+++ b/parquet/src/encodings/decoding.rs
@@ -433,7 +433,6 @@ pub struct DeltaBitPackDecoder<T: DataType> {
     initialized: bool,
 
     // Header info
-
     /// The number of values in each block
     block_size: usize,
     /// The number of values that remain to be read in the current page
@@ -444,7 +443,6 @@ pub struct DeltaBitPackDecoder<T: DataType> {
     values_per_mini_block: usize,
 
     // Per block info
-
     /// The minimum delta in the block
     min_delta: T::T,
     /// The byte offset of the end of the current block
@@ -839,7 +837,7 @@ impl<T: DataType> DeltaByteArrayDecoder<T> {
     }
 }
 
-impl<'m, T: DataType> Decoder<T> for DeltaByteArrayDecoder<T> {
+impl<T: DataType> Decoder<T> for DeltaByteArrayDecoder<T> {
     fn set_data(&mut self, data: ByteBufferPtr, num_values: usize) -> Result<()> {
         match T::get_physical_type() {
             Type::BYTE_ARRAY | Type::FIXED_LEN_BYTE_ARRAY => {