Use tidy to sort crate attributes for all compiler crates.

We already do this for a number of crates, e.g. `rustc_middle`,
`rustc_span`, `rustc_metadata`, `rustc_span`, `rustc_errors`.

For the ones we don't, in many cases the attributes are a mess.
- There is no consistency about order of attribute kinds (e.g.
  `allow`/`deny`/`feature`).
- Within attribute kind groups (e.g. the `feature` attributes),
  sometimes the order is alphabetical, and sometimes there is no
  particular order.
- Sometimes the attributes of a particular kind aren't even grouped
  all together, e.g. there might be a `feature`, then an `allow`, then
  another `feature`.

This commit extends the existing sorting to all compiler crates,
increasing consistency. If any new attribute line is added there is now
only one place it can go -- no need for arbitrary decisions.

Exceptions:
- `rustc_log`, `rustc_next_trait_solver` and `rustc_type_ir_macros`,
  because they have no crate attributes.
- `rustc_codegen_gcc`, because it's quasi-external to rustc (e.g. it's
  ignored in `rustfmt.toml`).

Author: nnethercote

compiler/rustc_abi/src/lib.rs

@@ -1,7 +1,9 @@
-#![cfg_attr(feature = "nightly", feature(step_trait))]
+// tidy-alphabetical-start
 #![cfg_attr(feature = "nightly", allow(internal_features))]
 #![cfg_attr(feature = "nightly", doc(rust_logo))]
 #![cfg_attr(feature = "nightly", feature(rustdoc_internals))]
+#![cfg_attr(feature = "nightly", feature(step_trait))]
+// tidy-alphabetical-end
 
 use std::fmt;
 use std::num::{NonZeroUsize, ParseIntError};

compiler/rustc_arena/src/lib.rs

@@ -7,23 +7,25 @@
 //!
 //! This crate implements several kinds of arena.
 
+// tidy-alphabetical-start
+#![allow(clippy::mut_from_ref)] // Arena allocators are one place where this pattern is fine.
+#![allow(internal_features)]
+#![cfg_attr(test, feature(test))]
+#![deny(unsafe_op_in_unsafe_fn)]
 #![doc(
     html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     test(no_crate_inject, attr(deny(warnings)))
 )]
 #![doc(rust_logo)]
-#![feature(rustdoc_internals)]
 #![feature(core_intrinsics)]
+#![feature(decl_macro)]
 #![feature(dropck_eyepatch)]
-#![feature(new_uninit)]
 #![feature(maybe_uninit_slice)]
-#![feature(decl_macro)]
+#![feature(new_uninit)]
 #![feature(rustc_attrs)]
-#![cfg_attr(test, feature(test))]
+#![feature(rustdoc_internals)]
 #![feature(strict_provenance)]
-#![deny(unsafe_op_in_unsafe_fn)]
-#![allow(internal_features)]
-#![allow(clippy::mut_from_ref)] // Arena allocators are one of the places where this pattern is fine.
+// tidy-alphabetical-end
 
 use smallvec::SmallVec;
 

compiler/rustc_ast/src/lib.rs

@@ -4,20 +4,22 @@
 //!
 //! This API is completely unstable and subject to change.
 
+// tidy-alphabetical-start
+#![allow(internal_features)]
 #![doc(
     html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/",
     test(attr(deny(warnings)))
 )]
 #![doc(rust_logo)]
-#![allow(internal_features)]
-#![feature(rustdoc_internals)]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
-#![feature(never_type)]
 #![feature(negative_impls)]
+#![feature(never_type)]
+#![feature(rustdoc_internals)]
 #![feature(stmt_expr_attributes)]
+// tidy-alphabetical-end
 
 pub mod util {
     pub mod case;

compiler/rustc_ast_ir/src/lib.rs

@@ -1,6 +1,8 @@
+// tidy-alphabetical-start
+#![cfg_attr(feature = "nightly", allow(internal_features))]
 #![cfg_attr(feature = "nightly", feature(never_type))]
 #![cfg_attr(feature = "nightly", feature(rustc_attrs))]
-#![cfg_attr(feature = "nightly", allow(internal_features))]
+// tidy-alphabetical-end
 
 #[cfg(feature = "nightly")]
 use rustc_macros::{Decodable, Encodable, HashStable_NoContext};

compiler/rustc_ast_lowering/src/lib.rs

@@ -30,12 +30,14 @@
 //! get confused if the spans from leaf AST nodes occur in multiple places
 //! in the HIR, especially for multiple identifiers.
 
+// tidy-alphabetical-start
 #![allow(internal_features)]
-#![feature(rustdoc_internals)]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
 #![feature(let_chains)]
+#![feature(rustdoc_internals)]
+// tidy-alphabetical-end
 
 use crate::errors::{AssocTyParentheses, AssocTyParenthesesSub, MisplacedImplTrait};
 use rustc_ast::node_id::NodeMap;

compiler/rustc_ast_passes/src/lib.rs

@@ -4,13 +4,15 @@
 //!
 //! The crate also contains other misc AST visitors, e.g. `node_count` and `show_span`.
 
+// tidy-alphabetical-start
 #![allow(internal_features)]
 #![doc(rust_logo)]
-#![feature(rustdoc_internals)]
 #![feature(box_patterns)]
 #![feature(if_let_guard)]
 #![feature(iter_is_partitioned)]
 #![feature(let_chains)]
+#![feature(rustdoc_internals)]
+// tidy-alphabetical-end
 
 pub mod ast_validation;
 mod errors;

compiler/rustc_ast_pretty/src/lib.rs

@@ -1,7 +1,9 @@
+// tidy-alphabetical-start
 #![allow(internal_features)]
-#![feature(rustdoc_internals)]
 #![doc(rust_logo)]
 #![feature(box_patterns)]
+#![feature(rustdoc_internals)]
+// tidy-alphabetical-end
 
 mod helpers;
 pub mod pp;

compiler/rustc_attr/src/lib.rs

@@ -4,10 +4,12 @@
 //! The goal is to move the definition of `MetaItem` and things that don't need to be in `syntax`
 //! to this crate.
 
+// tidy-alphabetical-start
 #![allow(internal_features)]
-#![feature(rustdoc_internals)]
 #![doc(rust_logo)]
 #![feature(let_chains)]
+#![feature(rustdoc_internals)]
+// tidy-alphabetical-end
 
 mod builtin;
 mod session_diagnostics;

compiler/rustc_baked_icu_data/src/lib.rs

@@ -20,10 +20,12 @@
 //! --cldr-tag latest --icuexport-tag latest -o src/data
 //! ```
 
+// tidy-alphabetical-start
+#![allow(elided_lifetimes_in_paths)]
 #![allow(internal_features)]
-#![feature(rustdoc_internals)]
 #![doc(rust_logo)]
-#![allow(elided_lifetimes_in_paths)]
+#![feature(rustdoc_internals)]
+// tidy-alphabetical-end
 
 mod data {
     include!("data/mod.rs");

compiler/rustc_borrowck/src/lib.rs

@@ -1,7 +1,7 @@
 //! This query borrow-checks the MIR to (further) ensure it is not broken.
 
+// tidy-alphabetical-start
 #![allow(internal_features)]
-#![feature(rustdoc_internals)]
 #![doc(rust_logo)]
 #![feature(assert_matches)]
 #![feature(box_patterns)]
@@ -10,8 +10,10 @@
 #![feature(min_specialization)]
 #![feature(never_type)]
 #![feature(rustc_attrs)]
+#![feature(rustdoc_internals)]
 #![feature(stmt_expr_attributes)]
 #![feature(try_blocks)]
+// tidy-alphabetical-end
 
 #[macro_use]
 extern crate tracing;