[ARROW-4678] [Rust] Minimize unstable feature usage

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.12.0
• Fix Version/s: 0.13.0
• Component/s: Rust
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/21208
• Assignee: Steven Fackler
• Reporter: Steven Fackler
• Created: 26/Feb/19 00:57
• Updated: 11/Jan/23 07:35
• Resolved: 28/Feb/19 08:33

Description

The Rust implementation currently uses quite a few nightly features. This is unfortunately a hard blocker on using these crates for many users.

Here's the list of currently use nightly features:

• type_ascription: Unused, can be trivially removed.
• rustc_private: Unused, can be trivially removed.
• box_syntax: Indefinitely far from stabilization, trivially replaceable with Box::new.
• box_patterns: Indefinitely far from stabilization, replaceable with some minor restructuring of a couple of matches.
• serde's alloc feature: Unused, can be trivially removed.
• try_from: Scheduled for stabilization in Rust 1.35.
• specialization: Actively being worked on - maybe ~1 year timeframe?
• packed_simd: Actively being worked on - maybe ~1 year timeframe?

The first set of features are easy enough to get rid of - I'll make a PR to do that (https://github.com/sfackler/arrow/tree/more-stable). I'm a bit less sure of what to do with specialization and packed_simd, though.

Issue Links

• relates to: ARROW-6717 [Rust] Support stable Rust
• links to: GitHub Pull Request #3764