From 32bf5ca1bbabb1a1c695aaccbcc664bdc5fd711b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Wed, 24 Jul 2019 12:20:43 +0200
Subject: [PATCH 1/2] Don't insta-free in UniqueArc::assume_init.

---
 components/servo_arc/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/components/servo_arc/lib.rs b/components/servo_arc/lib.rs
index 6e86ea7b5f3..1567fd3d421 100644
--- a/components/servo_arc/lib.rs
+++ b/components/servo_arc/lib.rs
@@ -144,7 +144,7 @@ impl<T> UniqueArc<mem::MaybeUninit<T>> {
     #[inline]
     pub unsafe fn assume_init(this: Self) -> UniqueArc<T> {
         UniqueArc(Arc {
-            p: this.0.p.cast(),
+            p: mem::ManuallyDrop::new(this).0.p.cast(),
             phantom: PhantomData,
         })
     }

From 62907afe1c6752f3b70fe7fabc288de09afb1866 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Wed, 24 Jul 2019 13:42:45 +0200
Subject: [PATCH 2/2] style: Properly refcount-log UniqueArcs created with
 new_uninitialized().

---
 components/servo_arc/lib.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/components/servo_arc/lib.rs b/components/servo_arc/lib.rs
index 1567fd3d421..ad4489c10bc 100644
--- a/components/servo_arc/lib.rs
+++ b/components/servo_arc/lib.rs
@@ -125,6 +125,12 @@ impl<T> UniqueArc<T> {
                 .unwrap_or_else(|| alloc::handle_alloc_error(layout))
                 .cast::<ArcInner<mem::MaybeUninit<T>>>();
             ptr::write(&mut p.as_mut().count, atomic::AtomicUsize::new(1));
+
+            #[cfg(feature = "gecko_refcount_logging")]
+            {
+                NS_LogCtor(p.as_ptr() as *mut _, b"ServoArc\0".as_ptr() as *const _, 8)
+            }
+
             UniqueArc(Arc {
                 p,
                 phantom: PhantomData,