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| author | bstrie <865233+bstrie@users.noreply.github.com> | 2021-07-27 18:50:34 -0400 |
|---|---|---|
| committer | bstrie <865233+bstrie@users.noreply.github.com> | 2021-11-08 13:07:20 -0500 |
| commit | 86c0ef8adcf2c60dc21a8a9b8f2d6992f2d7613c (patch) | |
| tree | 191747195cf97b1af521e27abac01e4d67b48a99 /library/alloc/src | |
| parent | 495322d776fd6f679cd8cd4ca02b8fa834da654b (diff) | |
| download | rust-86c0ef8adcf2c60dc21a8a9b8f2d6992f2d7613c.tar.gz rust-86c0ef8adcf2c60dc21a8a9b8f2d6992f2d7613c.zip | |
Add comments regarding superfluous `!Sync` impls
Diffstat (limited to 'library/alloc/src')
| -rw-r--r-- | library/alloc/src/rc.rs | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs index 4fb2f0c8530..03e33a1ff2b 100644 --- a/library/alloc/src/rc.rs +++ b/library/alloc/src/rc.rs @@ -313,6 +313,12 @@ pub struct Rc<T: ?Sized> { #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> !marker::Send for Rc<T> {} + +// Note that this negative impl isn't strictly necessary for correctness, +// as `Rc` transitively contains a `Cell`, which is itself `!Sync`. +// However, given how important `Rc`'s `!Sync`-ness is, +// having an explicit negative impl is nice for documentation purposes +// and results in nicer error messages. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> !marker::Sync for Rc<T> {} |