[ARROW-10108] [Rust] [Parquet] Fix compiler warning about unused return value

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: Rust
• External issue URL: https://github.com/apache/arrow/issues/26122
• Assignee: Neville Dipale
• Reporter: Andy Grove
• Created: 27/Sep/20 14:23
• Updated: 11/Jan/23 08:11
• Resolved: 04/Dec/20 23:11

Description

When compiling with latest nightly, this warning is produced:

warning: unused return value of `std::mem::replace` that must be used
   --> parquet/src/encodings/encoding.rs:391:9
    |
391 |         mem::replace(&mut self.hash_slots, new_hash_slots);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(unused_must_use)]` on by default
    = note: if you don't need the old value, you can just assign the new value directly