4a4098a00e
Support async recursive calls (as long as they have indirection) Before #101692, we stored coroutine witness types directly inside of the coroutine. That means that a coroutine could not contain itself (as a witness field) without creating a cycle in the type representation of the coroutine, which we detected with the `OpaqueTypeExpander`, which is used to detect cycles when expanding opaque types after that are inferred to contain themselves. After `-Zdrop-tracking-mir` was stabilized, we no longer store these generator witness fields directly, but instead behind a def-id based query. That means there is no technical obstacle in the compiler preventing coroutines from containing themselves per se, other than the fact that for a coroutine to have a non-infinite layout, it must contain itself wrapped in a layer of allocation indirection (like a `Box`). This means that it should be valid for this code to work: ``` async fn async_fibonacci(i: u32) -> u32 { if i == 0 || i == 1 { i } else { Box::pin(async_fibonacci(i - 1)).await + Box::pin(async_fibonacci(i - 2)).await } } ``` Whereas previously, you'd need to coerce the future to `Pin<Box<dyn Future<Output = ...>>` before `await`ing it, to prevent the async's desugared coroutine from containing itself across as await point. This PR does two things: 1. Only report an error if an opaque expansion cycle is detected *not* through coroutine witness fields. * Instead, if we find an opaque cycle through coroutine witness fields, we compute the layout of the coroutine. If that results in a cycle error, we report it as a recursive async fn. 4. Reworks the way we report layout errors having to do with coroutines, to make up for the diagnostic regressions introduced by (1.). We actually do even better now, pointing out the call sites of the recursion! |
||
|---|---|---|
| .cargo | ||
| .github | ||
| .vscode | ||
| assets | ||
| bench_data | ||
| crates | ||
| docs | ||
| editors/code | ||
| lib | ||
| xtask | ||
| .editorconfig | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitignore | ||
| Cargo.lock | ||
| Cargo.toml | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| PRIVACY.md | ||
| README.md | ||
| rust-bors.toml | ||
| rustfmt.toml | ||
| triagebot.toml | ||
rust-analyzer is a modular compiler frontend for the Rust language. It is a part of a larger rls-2.0 effort to create excellent IDE support for Rust.
Quick Start
https://rust-analyzer.github.io/manual.html#installation
Documentation
If you want to contribute to rust-analyzer or are just curious about how things work under the hood, check the ./docs/dev folder.
If you want to use rust-analyzer's language server with your editor of choice, check the manual folder. It also contains some tips & tricks to help you be more productive when using rust-analyzer.
Security and Privacy
See the corresponding sections of the manual.
Communication
For usage and troubleshooting requests, please use "IDEs and Editors" category of the Rust forum:
https://users.rust-lang.org/c/ide/14
For questions about development and implementation, join rust-analyzer working group on Zulip:
https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Frust-analyzer
Quick Links
- Website: https://rust-analyzer.github.io/
- Metrics: https://rust-analyzer.github.io/metrics/
- API docs: https://rust-lang.github.io/rust-analyzer/ide/
- Changelog: https://rust-analyzer.github.io/thisweek
License
rust-analyzer is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0).
See LICENSE-APACHE and LICENSE-MIT for details.