From 96ecaa17a7f333f3c374d5742565087a72798479 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 31 Jul 2021 03:57:49 -0700
Subject: [PATCH] Relocate Arc and Rc UnwindSafe impls

---
 library/alloc/src/lib.rs   |  1 -
 library/alloc/src/panic.rs | 11 -----------
 library/alloc/src/rc.rs    |  4 ++++
 library/alloc/src/sync.rs  |  4 ++++
 4 files changed, 8 insertions(+), 12 deletions(-)
 delete mode 100644 library/alloc/src/panic.rs

diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index 12a5868db74..d2ececaa975 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -177,7 +177,6 @@ mod boxed {
 pub mod borrow;
 pub mod collections;
 pub mod fmt;
-mod panic;
 pub mod prelude;
 pub mod raw_vec;
 pub mod rc;
diff --git a/library/alloc/src/panic.rs b/library/alloc/src/panic.rs
deleted file mode 100644
index b854be9f5ce..00000000000
--- a/library/alloc/src/panic.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-use crate::rc::Rc;
-use crate::sync::Arc;
-use core::panic::{RefUnwindSafe, UnwindSafe};
-
-// not covered via the Shared impl in libcore b/c the inner contents use
-// Cell/AtomicUsize, but the usage here is unwind safe so we can lift the
-// impl up one level to Arc/Rc itself
-#[stable(feature = "catch_unwind", since = "1.9.0")]
-impl<T: RefUnwindSafe + ?Sized> UnwindSafe for Rc<T> {}
-#[stable(feature = "catch_unwind", since = "1.9.0")]
-impl<T: RefUnwindSafe + ?Sized> UnwindSafe for Arc<T> {}
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index a1787ceac59..0b3079fa59d 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -262,6 +262,7 @@ use core::marker::{self, PhantomData, Unpin, Unsize};
 use core::mem::size_of_val;
 use core::mem::{self, align_of_val_raw, forget};
 use core::ops::{CoerceUnsized, Deref, DispatchFromDyn, Receiver};
+use core::panic::{RefUnwindSafe, UnwindSafe};
 #[cfg(not(no_global_oom_handling))]
 use core::pin::Pin;
 use core::ptr::{self, NonNull};
@@ -314,6 +315,9 @@ impl<T: ?Sized> !marker::Send for Rc<T> {}
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> !marker::Sync for Rc<T> {}
 
+#[stable(feature = "catch_unwind", since = "1.9.0")]
+impl<T: RefUnwindSafe + ?Sized> UnwindSafe for Rc<T> {}
+
 #[unstable(feature = "coerce_unsized", issue = "27732")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Rc<U>> for Rc<T> {}
 
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 78671c4f64e..3183a6db410 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -19,6 +19,7 @@ use core::marker::{PhantomData, Unpin, Unsize};
 use core::mem::size_of_val;
 use core::mem::{self, align_of_val_raw};
 use core::ops::{CoerceUnsized, Deref, DispatchFromDyn, Receiver};
+use core::panic::{RefUnwindSafe, UnwindSafe};
 use core::pin::Pin;
 use core::ptr::{self, NonNull};
 #[cfg(not(no_global_oom_handling))]
@@ -240,6 +241,9 @@ unsafe impl<T: ?Sized + Sync + Send> Send for Arc<T> {}
 #[stable(feature = "rust1", since = "1.0.0")]
 unsafe impl<T: ?Sized + Sync + Send> Sync for Arc<T> {}
 
+#[stable(feature = "catch_unwind", since = "1.9.0")]
+impl<T: RefUnwindSafe + ?Sized> UnwindSafe for Arc<T> {}
+
 #[unstable(feature = "coerce_unsized", issue = "27732")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Arc<U>> for Arc<T> {}