diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 7fea061766666..4da7e233889f0 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -34,7 +34,6 @@ use super::{
     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 8be8996e4c8f0..4e83ef0c6291b 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -120,7 +120,6 @@ use types::*;
 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 c9590ad06b05d..1b4bcb789d2da 100644
--- a/compiler/rustc_pattern_analysis/src/lib.rs
+++ b/compiler/rustc_pattern_analysis/src/lib.rs
@@ -21,9 +21,7 @@ rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 
 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 7c3553b60fddb..854295dc04818 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/alloc/src/testing/crash_test.rs b/library/alloc/src/testing/crash_test.rs
index bcf5f5f72510e..ff72f99b2cbed 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};
 
diff --git a/library/core/src/char/mod.rs b/library/core/src/char/mod.rs
index 26b463e25ea62..3c641a2e01c93 100644
--- a/library/core/src/char/mod.rs
+++ b/library/core/src/char/mod.rs
@@ -24,7 +24,6 @@ mod convert;
 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 @@ pub use self::convert::ParseCharError;
 #[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 a6a1a055e2983..e38ef1e147c76 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)]
@@ -33,10 +36,7 @@ pub use crate::convert::{AsMut, AsRef, From, Into};
 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};
diff --git a/library/core/src/prelude/mod.rs b/library/core/src/prelude/mod.rs
index ca33ef160e88b..496b78439ea6c 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 a8a47b69632f7..f2247e83ec5c5 100644
--- a/library/core/src/ptr/mod.rs
+++ b/library/core/src/ptr/mod.rs
@@ -1809,10 +1809,9 @@ pub(crate) const unsafe fn align_offset<T: Sized>(p: *const T, a: usize) -> usiz
     // 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 e1faa407d54c5..5ddd9f7476dd8 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 @@ mod unicode_data;
 /// [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 66aeb35aceec0..b11670d88c277 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -469,7 +469,6 @@ pub mod rt;
 // 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 39a42f4e17fec..b31dc06f8dfbd 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 usercalls {
         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 055ab7eb6d987..b231bd871b3b4 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 2d4639342bf85..0c610ba67e65c 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 c0a1c5f5594ae..82ededa58001a 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 8dfb733043e77..d8fe06d1973c9 100644
--- a/library/std/src/sys/pal/wasi/mod.rs
+++ b/library/std/src/sys/pal/wasi/mod.rs
@@ -39,12 +39,15 @@ pub mod time;
 #[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 7af0917b8ed42..0930d2e22fa8d 100644
--- a/library/std/src/sys/pal/wasip2/mod.rs
+++ b/library/std/src/sys/pal/wasip2/mod.rs
@@ -41,13 +41,16 @@ pub mod time;
 #[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 7aff7fe1fdd68..71cb796b93705 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};