From 1efd9958a35b79841cbf6118fef73a34811dbcfe Mon Sep 17 00:00:00 2001
From: John-John Tedro <udoprog@tedro.se>
Date: Thu, 23 Jan 2020 19:05:20 +0100
Subject: [PATCH] Assert that the alignment of Shared is appropriate (#362)

---
 src/bytes.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/bytes.rs b/src/bytes.rs
index d8af5b5..35a3c75 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -905,6 +905,12 @@ struct Shared {
     ref_cnt: AtomicUsize,
 }
 
+// Assert that the alignment of `Shared` is divisible by 2.
+// This is a necessary invariant since we depend on allocating `Shared` a
+// shared object to implicitly carry the `KIND_ARC` flag in its pointer.
+// This flag is set when the LSB is 0.
+const _: [(); 0 - mem::align_of::<Shared>() % 2] = []; // Assert that the alignment of `Shared` is divisible by 2.
+
 static SHARED_VTABLE: Vtable = Vtable {
     clone: shared_clone,
     drop: shared_drop,