Replace if with if and only if in the definition dox of Sync

The old text was: "The precise definition is: a type T is Sync if &T is Send."

Since we've also got
```
impl<'a, T> Send for &'a T 
where
    T: Sync + ?Sized,
```
I purpose we can change the `if` to `if and only if` to make it more precise.
This commit is contained in:
CrLF0710 2018-05-29 15:58:50 +08:00
parent efc508ba4c
commit 8e90a2d02f

View File

@ -294,7 +294,7 @@ pub trait Copy : Clone {
/// This trait is automatically implemented when the compiler determines
/// it's appropriate.
///
/// The precise definition is: a type `T` is `Sync` if `&T` is
/// The precise definition is: a type `T` is `Sync` if and only if `&T` is
/// [`Send`][send]. In other words, if there is no possibility of
/// [undefined behavior][ub] (including data races) when passing
/// `&T` references between threads.