rust/compiler/rustc_ast
Dylan DPC 20bf34f8c5
Rollup merge of #94461 - jhpratt:2024-edition, r=pnkfelix
Create (unstable) 2024 edition

[On Zulip](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Deprecating.20macro.20scoping.20shenanigans/near/272860652), there was a small aside regarding creating the 2024 edition now as opposed to later. There was a reasonable amount of support and no stated opposition.

This change creates the 2024 edition in the compiler and creates a prelude for the 2024 edition. There is no current difference between the 2021 and 2024 editions. Cargo and other tools will need to be updated separately, as it's not in the same repository. This change permits the vast majority of work towards the next edition to proceed _now_ instead of waiting until 2024.

For sanity purposes, I've merged the "hello" UI tests into a single file with multiple revisions. Otherwise we'd end up with a file per edition, despite them being essentially identical.

````@rustbot```` label +T-lang +S-waiting-on-review

Not sure on the relevant team, to be honest.
2022-04-15 20:50:43 +02:00
..
src Rollup merge of #94461 - jhpratt:2024-edition, r=pnkfelix 2022-04-15 20:50:43 +02:00
Cargo.toml Migrate to 2021 2021-09-20 22:21:42 -04:00
README.md docs(rustc_ast): update crate descriptions 2021-11-02 21:11:17 -05:00

The rustc_ast crate contains those things concerned purely with syntax that is, the AST ("abstract syntax tree"), along with some definitions for tokens and token streams, data structures/traits for mutating ASTs, and shared definitions for other AST-related parts of the compiler (like the lexer and macro-expansion).

For more information about how these things work in rustc, see the rustc dev guide: