---

yaml
---
r: 175572
b: refs/heads/auto
c: a7525bc
h: refs/heads/master
v: v3

Author: Aatch

[refs]

@@ -10,7 +10,7 @@ refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/tags/release-0.3.1: 495bae036dfe5ec6ceafd3312b4dca48741e845b
 refs/tags/release-0.4: e828ea2080499553b97dfe33b3f4d472b4562ad7
 refs/tags/release-0.5: 7e3bcfbf21278251ee936ad53e92e9b719702d73
-refs/heads/auto: 9bbfd681c9fa47f462a89e8f5eedd3fa2a5de2e7
+refs/heads/auto: a7525bc4c8eb8507a5c248d29286e77133217cf3
 refs/heads/servo: af82457af293e2a842ba6b7759b70288da276167
 refs/tags/release-0.6: b4ebcfa1812664df5e142f0134a5faea3918544c
 refs/tags/0.1: b19db808c2793fe2976759b85a355c3ad8c8b336

branches/auto/src/liballoc/rc.rs

@@ -909,6 +909,8 @@ trait RcBoxPtr<T> {
     fn inc_strong(&self) {
         let strong = self.strong();
         // The reference count is always at least one unless we're about to drop the type
+        // This allows the bulk of the destructor to be omitted in cases where we know that
+        // the reference count must be > 0.
         unsafe { assume(strong > 0); }
         self.inner().strong.set(strong + 1);
     }
@@ -917,6 +919,8 @@ trait RcBoxPtr<T> {
     fn dec_strong(&self) {
         let strong = self.strong();
         // The reference count is always at least one unless we're about to drop the type
+        // This allows the bulk of the destructor to be omitted in cases where we know that
+        // the reference count must be > 0
         unsafe { assume(strong > 0); }
         self.inner().strong.set(strong - 1);
     }
@@ -936,7 +940,9 @@ impl<T> RcBoxPtr<T> for Rc<T> {
     fn inner(&self) -> &RcBox<T> {
         unsafe {
             // Safe to assume this here, as if it weren't true, we'd be breaking
-            // the contract anyway
+            // the contract anyway.
+            // This allows the null check to be elided in the destructor if we
+            // manipulated the reference count in the same function.
             assume(!self._ptr.is_null());
             &(**self._ptr)
         }
@@ -949,6 +955,8 @@ impl<T> RcBoxPtr<T> for Weak<T> {
         unsafe {
             // Safe to assume this here, as if it weren't true, we'd be breaking
             // the contract anyway
+            // This allows the null check to be elided in the destructor if we
+            // manipulated the reference count in the same function.
             assume(!self._ptr.is_null());
             &(**self._ptr)
         }