From d9fde2504a1e77765e9505d2346a15867ad5a4b8 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Thu, 20 Jun 2024 19:55:38 +1000
Subject: [PATCH 1/3] Merge some `core::iter` entries.

---
 library/core/src/prelude/common.rs | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/library/core/src/prelude/common.rs b/library/core/src/prelude/common.rs
index a6a1a055e29..bdaa1661354 100644
--- a/library/core/src/prelude/common.rs
+++ b/library/core/src/prelude/common.rs
@@ -33,10 +33,7 @@
 pub use crate::default::Default;
 #[stable(feature = "core_prelude", since = "1.4.0")]
 #[doc(no_inline)]
-pub use crate::iter::{DoubleEndedIterator, ExactSizeIterator};
-#[stable(feature = "core_prelude", since = "1.4.0")]
-#[doc(no_inline)]
-pub use crate::iter::{Extend, IntoIterator, Iterator};
+pub use crate::iter::{DoubleEndedIterator, ExactSizeIterator, Extend, IntoIterator, Iterator};
 #[stable(feature = "core_prelude", since = "1.4.0")]
 #[doc(no_inline)]
 pub use crate::option::Option::{self, None, Some};

From 75b6ec980059292faa9cdf538b552faf6b70fb29 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Thu, 20 Jun 2024 15:44:13 +1000
Subject: [PATCH 2/3] Avoid comments that describe multiple `use` items.

There are some comments describing multiple subsequent `use` items. When
the big `use` reformatting happens some of these `use` items will be
reordered, possibly moving them away from the comment. With this
additional level of formatting it's not really feasible to have comments
of this type. This commit removes them in various ways:

- merging separate `use` items when appropriate;

- inserting blank lines between the comment and the first `use` item;

- outright deletion (for comments that are relatively low-value);

- adding a separate "top-level" comment.

We also entirely skip formatting for four library files that contain
nothing but `pub use` re-exports, where reordering would be painful.
---
 .../src/interpret/validity.rs                 |  1 -
 compiler/rustc_lint/src/lib.rs                |  1 -
 compiler/rustc_pattern_analysis/src/lib.rs    |  4 +--
 .../rustc_smir/src/rustc_internal/internal.rs |  1 +
 library/core/src/char/mod.rs                  |  6 ++---
 library/core/src/prelude/common.rs            |  3 +++
 library/core/src/prelude/mod.rs               |  3 +++
 library/core/src/ptr/mod.rs                   |  5 ++--
 library/core/src/unicode/mod.rs               | 26 +++++++++----------
 library/std/src/lib.rs                        |  1 -
 library/std/src/os/fortanix_sgx/mod.rs        |  1 -
 library/std/src/prelude/common.rs             |  3 +++
 library/std/src/prelude/mod.rs                |  3 +++
 library/std/src/rt.rs                         |  1 -
 library/std/src/sys/pal/wasi/mod.rs           |  9 ++++---
 library/std/src/sys/pal/wasip2/mod.rs         |  9 ++++---
 library/test/src/lib.rs                       |  1 -
 17 files changed, 43 insertions(+), 35 deletions(-)

diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 7fea0617666..4da7e233889 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -34,7 +34,6 @@
     Pointer, Projectable, Scalar, ValueVisitor,
 };
 
-// for the validation errors
 use super::InterpError::UndefinedBehavior as Ub;
 use super::InterpError::Unsupported as Unsup;
 use super::UndefinedBehaviorInfo::*;
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index 8be8996e4c8..4e83ef0c629 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -120,7 +120,6 @@
 use unit_bindings::*;
 use unused::*;
 
-/// Useful for other parts of the compiler / Clippy.
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{CheckLintNameResult, FindLintError, LintStore};
 pub use context::{EarlyContext, LateContext, LintContext};
diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs
index c9590ad06b0..1b4bcb789d2 100644
--- a/compiler/rustc_pattern_analysis/src/lib.rs
+++ b/compiler/rustc_pattern_analysis/src/lib.rs
@@ -21,9 +21,7 @@
 
 use std::fmt;
 
-// Re-exports to avoid rustc_index version issues.
-pub use rustc_index::Idx;
-pub use rustc_index::IndexVec;
+pub use rustc_index::{Idx, IndexVec}; // re-exported to avoid rustc_index version issues
 
 #[cfg(feature = "rustc")]
 use rustc_middle::ty::Ty;
diff --git a/compiler/rustc_smir/src/rustc_internal/internal.rs b/compiler/rustc_smir/src/rustc_internal/internal.rs
index 7c3553b60fd..854295dc048 100644
--- a/compiler/rustc_smir/src/rustc_internal/internal.rs
+++ b/compiler/rustc_smir/src/rustc_internal/internal.rs
@@ -4,6 +4,7 @@
 //! due to incomplete stable coverage.
 
 // Prefer importing stable_mir over internal rustc constructs to make this file more readable.
+
 use crate::rustc_smir::Tables;
 use rustc_middle::ty::{self as rustc_ty, Const as InternalConst, Ty as InternalTy, TyCtxt};
 use rustc_span::Symbol;
diff --git a/library/core/src/char/mod.rs b/library/core/src/char/mod.rs
index 26b463e25ea..3c641a2e01c 100644
--- a/library/core/src/char/mod.rs
+++ b/library/core/src/char/mod.rs
@@ -24,7 +24,6 @@
 mod decode;
 mod methods;
 
-// stable re-exports
 #[stable(feature = "try_from", since = "1.34.0")]
 pub use self::convert::CharTryFromError;
 #[stable(feature = "char_from_str", since = "1.20.0")]
@@ -32,11 +31,10 @@
 #[stable(feature = "decode_utf16", since = "1.9.0")]
 pub use self::decode::{DecodeUtf16, DecodeUtf16Error};
 
-// perma-unstable re-exports
 #[unstable(feature = "char_internals", reason = "exposed only for libstd", issue = "none")]
-pub use self::methods::encode_utf16_raw;
+pub use self::methods::encode_utf16_raw; // perma-unstable
 #[unstable(feature = "char_internals", reason = "exposed only for libstd", issue = "none")]
-pub use self::methods::encode_utf8_raw;
+pub use self::methods::encode_utf8_raw; // perma-unstable
 
 use crate::ascii;
 use crate::error::Error;
diff --git a/library/core/src/prelude/common.rs b/library/core/src/prelude/common.rs
index bdaa1661354..e38ef1e147c 100644
--- a/library/core/src/prelude/common.rs
+++ b/library/core/src/prelude/common.rs
@@ -2,6 +2,9 @@
 //!
 //! See the [module-level documentation](super) for more.
 
+// No formatting: this file is nothing but re-exports, and their order is worth preserving.
+#![cfg_attr(rustfmt, rustfmt::skip)]
+
 // Re-exported core operators
 #[stable(feature = "core_prelude", since = "1.4.0")]
 #[doc(no_inline)]
diff --git a/library/core/src/prelude/mod.rs b/library/core/src/prelude/mod.rs
index ca33ef160e8..496b78439ea 100644
--- a/library/core/src/prelude/mod.rs
+++ b/library/core/src/prelude/mod.rs
@@ -4,6 +4,9 @@
 //! This module is imported by default when `#![no_std]` is used in the same
 //! manner as the standard library's prelude.
 
+// No formatting: this file is nothing but re-exports, and their order is worth preserving.
+#![cfg_attr(rustfmt, rustfmt::skip)]
+
 #![stable(feature = "core_prelude", since = "1.4.0")]
 
 mod common;
diff --git a/library/core/src/ptr/mod.rs b/library/core/src/ptr/mod.rs
index a8a47b69632..f2247e83ec5 100644
--- a/library/core/src/ptr/mod.rs
+++ b/library/core/src/ptr/mod.rs
@@ -1809,10 +1809,9 @@ pub unsafe fn write_volatile<T>(dst: *mut T, src: T) {
     // FIXME(#75598): Direct use of these intrinsics improves codegen significantly at opt-level <=
     // 1, where the method versions of these operations are not inlined.
     use intrinsics::{
-        assume, cttz_nonzero, exact_div, mul_with_overflow, unchecked_rem, unchecked_sub,
-        wrapping_add, wrapping_mul, wrapping_sub,
+        assume, cttz_nonzero, exact_div, mul_with_overflow, unchecked_rem, unchecked_shl,
+        unchecked_shr, unchecked_sub, wrapping_add, wrapping_mul, wrapping_sub,
     };
-    use intrinsics::{unchecked_shl, unchecked_shr};
 
     /// Calculate multiplicative modular inverse of `x` modulo `m`.
     ///
diff --git a/library/core/src/unicode/mod.rs b/library/core/src/unicode/mod.rs
index e1faa407d54..5ddd9f7476d 100644
--- a/library/core/src/unicode/mod.rs
+++ b/library/core/src/unicode/mod.rs
@@ -1,6 +1,19 @@
 #![unstable(feature = "unicode_internals", issue = "none")]
 #![allow(missing_docs)]
 
+// The `pub use` ones are for use in alloc, and are not re-exported in std.
+
+pub(crate) use unicode_data::alphabetic::lookup as Alphabetic;
+pub use unicode_data::case_ignorable::lookup as Case_Ignorable;
+pub use unicode_data::cased::lookup as Cased;
+pub(crate) use unicode_data::cc::lookup as Cc;
+pub use unicode_data::conversions;
+pub(crate) use unicode_data::grapheme_extend::lookup as Grapheme_Extend;
+pub(crate) use unicode_data::lowercase::lookup as Lowercase;
+pub(crate) use unicode_data::n::lookup as N;
+pub(crate) use unicode_data::uppercase::lookup as Uppercase;
+pub(crate) use unicode_data::white_space::lookup as White_Space;
+
 pub(crate) mod printable;
 mod unicode_data;
 
@@ -16,16 +29,3 @@
 /// [Unicode 11.0 or later, Section 3.1 Versions of the Unicode Standard](https://www.unicode.org/versions/Unicode11.0.0/ch03.pdf#page=4).
 #[stable(feature = "unicode_version", since = "1.45.0")]
 pub const UNICODE_VERSION: (u8, u8, u8) = unicode_data::UNICODE_VERSION;
-
-// For use in alloc, not re-exported in std.
-pub use unicode_data::{
-    case_ignorable::lookup as Case_Ignorable, cased::lookup as Cased, conversions,
-};
-
-pub(crate) use unicode_data::alphabetic::lookup as Alphabetic;
-pub(crate) use unicode_data::cc::lookup as Cc;
-pub(crate) use unicode_data::grapheme_extend::lookup as Grapheme_Extend;
-pub(crate) use unicode_data::lowercase::lookup as Lowercase;
-pub(crate) use unicode_data::n::lookup as N;
-pub(crate) use unicode_data::uppercase::lookup as Uppercase;
-pub(crate) use unicode_data::white_space::lookup as White_Space;
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 66aeb35acee..b11670d88c2 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -469,7 +469,6 @@
 // The Rust prelude
 pub mod prelude;
 
-// Public module declarations and re-exports
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use alloc_crate::borrow;
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/std/src/os/fortanix_sgx/mod.rs b/library/std/src/os/fortanix_sgx/mod.rs
index 39a42f4e17f..b31dc06f8df 100644
--- a/library/std/src/os/fortanix_sgx/mod.rs
+++ b/library/std/src/os/fortanix_sgx/mod.rs
@@ -28,7 +28,6 @@ pub mod raw {
         pub use crate::sys::abi::usercalls::raw::{do_usercall, Usercalls as UsercallNrs};
         pub use crate::sys::abi::usercalls::raw::{Register, RegisterArgument, ReturnValue};
 
-        // fortanix-sgx-abi re-exports
         pub use crate::sys::abi::usercalls::raw::Error;
         pub use crate::sys::abi::usercalls::raw::{
             ByteBuffer, Cancel, FifoDescriptor, Return, Usercall,
diff --git a/library/std/src/prelude/common.rs b/library/std/src/prelude/common.rs
index 055ab7eb6d9..b231bd871b3 100644
--- a/library/std/src/prelude/common.rs
+++ b/library/std/src/prelude/common.rs
@@ -2,6 +2,9 @@
 //!
 //! See the [module-level documentation](super) for more.
 
+// No formatting: this file is nothing but re-exports, and their order is worth preserving.
+#![cfg_attr(rustfmt, rustfmt::skip)]
+
 // Re-exported core operators
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)]
diff --git a/library/std/src/prelude/mod.rs b/library/std/src/prelude/mod.rs
index 2d4639342bf..0c610ba67e6 100644
--- a/library/std/src/prelude/mod.rs
+++ b/library/std/src/prelude/mod.rs
@@ -95,6 +95,9 @@
 //! [book-enums]: ../../book/ch06-01-defining-an-enum.html
 //! [book-iter]: ../../book/ch13-02-iterators.html
 
+// No formatting: this file is nothing but re-exports, and their order is worth preserving.
+#![cfg_attr(rustfmt, rustfmt::skip)]
+
 #![stable(feature = "rust1", since = "1.0.0")]
 
 mod common;
diff --git a/library/std/src/rt.rs b/library/std/src/rt.rs
index c0a1c5f5594..82ededa5800 100644
--- a/library/std/src/rt.rs
+++ b/library/std/src/rt.rs
@@ -16,7 +16,6 @@
 #![deny(unsafe_op_in_unsafe_fn)]
 #![allow(unused_macros)]
 
-// Re-export some of our utilities which are expected by other crates.
 pub use crate::panicking::{begin_panic, panic_count};
 pub use core::panicking::{panic_display, panic_fmt};
 
diff --git a/library/std/src/sys/pal/wasi/mod.rs b/library/std/src/sys/pal/wasi/mod.rs
index 8dfb733043e..d8fe06d1973 100644
--- a/library/std/src/sys/pal/wasi/mod.rs
+++ b/library/std/src/sys/pal/wasi/mod.rs
@@ -39,12 +39,15 @@
 #[deny(unsafe_op_in_unsafe_fn)]
 #[allow(unused)]
 mod common;
+
 pub use common::*;
 
 mod helpers;
-// These exports are listed individually to work around Rust's glob import
-// conflict rules. If we glob export `helpers` and `common` together, then
-// the compiler complains about conflicts.
+
+// The following exports are listed individually to work around Rust's glob
+// import conflict rules. If we glob export `helpers` and `common` together,
+// then the compiler complains about conflicts.
+
 pub use helpers::abort_internal;
 pub use helpers::decode_error_kind;
 use helpers::err2io;
diff --git a/library/std/src/sys/pal/wasip2/mod.rs b/library/std/src/sys/pal/wasip2/mod.rs
index 7af0917b8ed..0930d2e22fa 100644
--- a/library/std/src/sys/pal/wasip2/mod.rs
+++ b/library/std/src/sys/pal/wasip2/mod.rs
@@ -41,13 +41,16 @@
 #[deny(unsafe_op_in_unsafe_fn)]
 #[allow(unused)]
 mod common;
+
 pub use common::*;
 
 #[path = "../wasi/helpers.rs"]
 mod helpers;
-// These exports are listed individually to work around Rust's glob import
-// conflict rules. If we glob export `helpers` and `common` together, then
-// the compiler complains about conflicts.
+
+// The following exports are listed individually to work around Rust's glob
+// import conflict rules. If we glob export `helpers` and `common` together,
+// then the compiler complains about conflicts.
+
 pub use helpers::abort_internal;
 pub use helpers::decode_error_kind;
 use helpers::err2io;
diff --git a/library/test/src/lib.rs b/library/test/src/lib.rs
index 7aff7fe1fdd..71cb796b937 100644
--- a/library/test/src/lib.rs
+++ b/library/test/src/lib.rs
@@ -25,7 +25,6 @@
 #![feature(test)]
 #![allow(internal_features)]
 
-// Public reexports
 pub use self::bench::{black_box, Bencher};
 pub use self::console::run_tests_console;
 pub use self::options::{ColorConfig, Options, OutputFormat, RunIgnored, ShouldPanic};

From 7f0ccfe69d7c79ed84a7fb23081fd2d15434da62 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Thu, 20 Jun 2024 20:10:25 +1000
Subject: [PATCH 3/3] Adjust some comments on individual `use` declarations.

When we do the big `use` reformatting there are a tiny number of cases
where rustfmt moves a comment from one `use` item to another in an
undesirable way. This commit pre-emptively rearranges things to prevent
this from happening.
---
 library/alloc/src/testing/crash_test.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/library/alloc/src/testing/crash_test.rs b/library/alloc/src/testing/crash_test.rs
index bcf5f5f7251..ff72f99b2cb 100644
--- a/library/alloc/src/testing/crash_test.rs
+++ b/library/alloc/src/testing/crash_test.rs
@@ -1,5 +1,4 @@
-// We avoid relying on anything else in the crate, apart from the `Debug` trait.
-use crate::fmt::Debug;
+use crate::fmt::Debug; // the `Debug` trait is the only thing we use from `crate::fmt`
 use std::cmp::Ordering;
 use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};