[Migrated] Rust Language Support

Issue automatically imported from old repo: https://github.com/EmbarkStudios/rust-gpu/issues/78
Old labels: t: tracking issue
Originally creatd by XAMPPRocky on 2020-10-21T09:57:13Z 👍: 18 🎉: 5 🚀: 2 👀: 5

This is a tracking issue for adding support for using Rust language features and the core library with rustc_codegen_spirv.

Language Support

• Closures
• Enums
  • Data-less enums. enum Foo { A, B }
  • Algebraic data types. enum Option<T> { Some(T), None }
• Loops
  • loop
  • while
  • for
• if
• match
• Proc macros
• Try (?) operator
• 128 bit integers
• union
• Compiles on stable
  • Blocked on stabilisation of -Z codegen-backend, also see https://github.com/rust-lang/rust/issues/77933

Compiler & Library Support

• Debug builds
  • Blocked on #81, #186
• Iterators
• Option<T>

Features that don't work

• Dynamic Dispatch
• Pointer casts
• Unsized slices (&[T])

About Tracking Issues

Tracking issues are meant for providing status updates on the progress of a feature, it's not meant for bug reports or discussions on a feature. Please instead file a new issue or join the #rust-gpu channel on Discord.

This is a broad tracking issue rather than a self-contained task. Start by reviewing the unchecked items under Language Support and Compiler & Library Support, including linked issues such as #196, #415, #192, #81, #186, and #234. Done means completing a specific linked feature and updating the corresponding checklist item.