From 7033468a67c0e39b2e34de2b43f78a29d101861d Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Thu, 26 Sep 2024 22:10:04 -0400
Subject: [PATCH 1/2] Mark some more types as having insignificant dtor

---
 library/alloc/src/ffi/c_str.rs             | 1 +
 library/std/src/io/error/repr_bitpacked.rs | 1 +
 2 files changed, 2 insertions(+)

diff --git a/library/alloc/src/ffi/c_str.rs b/library/alloc/src/ffi/c_str.rs
index 797d591a8b5..d496899e72b 100644
--- a/library/alloc/src/ffi/c_str.rs
+++ b/library/alloc/src/ffi/c_str.rs
@@ -696,6 +696,7 @@ impl CString {
 // memory-unsafe code from working by accident. Inline
 // to prevent LLVM from optimizing it away in debug builds.
 #[stable(feature = "cstring_drop", since = "1.13.0")]
+#[rustc_insignificant_dtor]
 impl Drop for CString {
     #[inline]
     fn drop(&mut self) {
diff --git a/library/std/src/io/error/repr_bitpacked.rs b/library/std/src/io/error/repr_bitpacked.rs
index 80ba8455df3..a839a2fbac1 100644
--- a/library/std/src/io/error/repr_bitpacked.rs
+++ b/library/std/src/io/error/repr_bitpacked.rs
@@ -124,6 +124,7 @@ const TAG_SIMPLE: usize = 0b11;
 /// is_unwind_safe::<std::io::Error>();
 /// ```
 #[repr(transparent)]
+#[rustc_insignificant_dtor]
 pub(super) struct Repr(NonNull<()>, PhantomData<ErrorData<Box<Custom>>>);
 
 // All the types `Repr` stores internally are Send + Sync, and so is it.

From 24290efafffb83514da4e37f5f42a962d0e9bb1f Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Fri, 27 Sep 2024 11:59:35 -0400
Subject: [PATCH 2/2] Mark some more smart pointers as insignificant

---
 library/alloc/src/boxed.rs | 1 +
 library/alloc/src/sync.rs  | 1 +
 2 files changed, 2 insertions(+)

diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index 6421504b896..5f207295683 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -228,6 +228,7 @@ mod thin;
 #[lang = "owned_box"]
 #[fundamental]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_insignificant_dtor]
 // The declaration of the `Box` struct must be kept in sync with the
 // compiler or ICEs will happen.
 pub struct Box<
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index ced789c4f92..5d099a49854 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -237,6 +237,7 @@ macro_rules! acquire {
 /// [rc_examples]: crate::rc#examples
 #[cfg_attr(not(test), rustc_diagnostic_item = "Arc")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_insignificant_dtor]
 pub struct Arc<
     T: ?Sized,
     #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,