From 8505082f168eb44407352dd14d591918af86d3a2 Mon Sep 17 00:00:00 2001
From: Alyssa Haroldsen <kupiakos@google.com>
Date: Thu, 14 Dec 2023 14:09:17 -0800
Subject: [PATCH] Improve thread safety docs/bounds for PrimitiveMut

PiperOrigin-RevId: 591047379
---
 rust/primitive.rs | 2 ++
 rust/vtable.rs    | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/rust/primitive.rs b/rust/primitive.rs
index ea742181bf9f6..193901bb4b443 100644
--- a/rust/primitive.rs
+++ b/rust/primitive.rs
@@ -37,6 +37,8 @@ impl<'msg, T> PrimitiveMut<'msg, T> {
     }
 }
 
+// SAFETY: all `T` that can perform mutations don't mutate through a shared
+// reference.
 unsafe impl<'msg, T> Sync for PrimitiveMut<'msg, T> {}
 
 impl<'msg, T> PrimitiveMut<'msg, T>
diff --git a/rust/vtable.rs b/rust/vtable.rs
index 2691125b46cd2..311809608369b 100644
--- a/rust/vtable.rs
+++ b/rust/vtable.rs
@@ -432,6 +432,8 @@ pub trait PrimitiveWithRawVTable:
     + Debug
     + 'static
     + ProxiedWithPresence
+    + Sync
+    + Send
     + for<'msg> Proxied<View<'msg> = Self, Mut<'msg> = PrimitiveMut<'msg, Self>>
 {
 }