ARROW-11602: [Rust] Clippy lints

rust/datafusion/src/execution/context.rs

@@ -172,7 +172,7 @@ impl ExecutionContext {
         // create a query planner
         let state = self.state.lock().unwrap().clone();
         let query_planner = SqlToRel::new(&state);
-        Ok(query_planner.statement_to_plan(&statements[0])?)
+        query_planner.statement_to_plan(&statements[0])
     }
 
     /// Registers a variable provider within this context.

rust/datafusion/src/physical_plan/functions.rs

@@ -474,7 +474,7 @@ pub fn create_physical_expr(
         BuiltinScalarFunction::DateTrunc => {
             |args| Ok(Arc::new(datetime_expressions::date_trunc(args)?))
         }
-        BuiltinScalarFunction::Array => |args| Ok(array_expressions::array(args)?),
+        BuiltinScalarFunction::Array => |args| array_expressions::array(args),
     });
     // coerce
     let args = coerce(args, input_schema, &signature(fun))?;

rust/parquet/src/arrow/arrow_reader.rs

@@ -147,7 +147,7 @@ impl ArrowReader for ParquetFileArrowReader {
             self.file_reader.clone(),
         )?;
 
-        Ok(ParquetRecordBatchReader::try_new(batch_size, array_reader)?)
+        ParquetRecordBatchReader::try_new(batch_size, array_reader)
     }
 }
 

rust/parquet/src/compression.rs

@@ -208,7 +208,7 @@ mod brotli_codec {
                 BROTLI_DEFAULT_COMPRESSION_QUALITY,
                 BROTLI_DEFAULT_LG_WINDOW_SIZE,
             );
-            encoder.write_all(&input_buf[..])?;
+            encoder.write_all(input_buf)?;
             encoder.flush().map_err(|e| e.into())
         }
     }
@@ -308,7 +308,7 @@ mod zstd_codec {
 
         fn compress(&mut self, input_buf: &[u8], output_buf: &mut Vec<u8>) -> Result<()> {
             let mut encoder = zstd::Encoder::new(output_buf, ZSTD_COMPRESSION_LEVEL)?;
-            encoder.write_all(&input_buf[..])?;
+            encoder.write_all(input_buf)?;
             match encoder.finish() {
                 Ok(_) => Ok(()),
                 Err(e) => Err(e.into()),

rust/parquet/src/encodings/decoding.rs

@@ -995,7 +995,7 @@ mod tests {
         let mut decoder: PlainDecoder<T> = PlainDecoder::new(type_length);
         let result = decoder.set_data(data, num_values);
         assert!(result.is_ok());
-        let result = decoder.get(&mut buffer[..]);
+        let result = decoder.get(buffer);
         assert!(result.is_ok());
         assert_eq!(decoder.values_left(), 0);
         assert_eq!(buffer, expected);
@@ -1013,7 +1013,7 @@ mod tests {
         let mut decoder: PlainDecoder<T> = PlainDecoder::new(type_length);
         let result = decoder.set_data(data, num_values);
         assert!(result.is_ok());
-        let result = decoder.get_spaced(&mut buffer[..], num_nulls, valid_bits);
+        let result = decoder.get_spaced(buffer, num_nulls, valid_bits);
         assert!(result.is_ok());
         assert_eq!(num_values + num_nulls, result.unwrap());
         assert_eq!(decoder.values_left(), 0);

rust/parquet/src/schema/parser.rs

@@ -345,7 +345,7 @@ impl<'a> Parser<'a> {
         if let Some(id) = id {
             builder = builder.with_id(id);
         }
-        Ok(builder.build()?)
+        builder.build()
     }
 }