mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Warn against relying on ?Sized being last

Browse Source
This commit is contained in:
Mark Rousskov 2019-12-21 20:35:41 -05:00
parent 5535c25314
commit a34c2677af
2 changed files with 4 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/liballoc/rc.rs
View File

@ -2106,6 +2106,8 @@ impl<T: ?Sized> Unpin for Rc<T> { }
unsafe fn data_offset<T: ?Sized>(ptr: *const T) -> isize {
// Align the unsized value to the end of the `RcBox`.
// Because it is ?Sized, it will always be the last field in memory.
// Note: This is a detail of the current implementation of the compiler,
// and is not a guaranteed language detail. Do not rely on it outside of std.
data_offset_align(align_of_val(&*ptr))
}

2
src/liballoc/sync.rs
View File

@ -2161,6 +2161,8 @@ impl<T: ?Sized> Unpin for Arc<T> { }
unsafe fn data_offset<T: ?Sized>(ptr: *const T) -> isize {
// Align the unsized value to the end of the `ArcInner`.
// Because it is `?Sized`, it will always be the last field in memory.
// Note: This is a detail of the current implementation of the compiler,
// and is not a guaranteed language detail. Do not rely on it outside of std.
data_offset_align(align_of_val(&*ptr))
}