diff options
| -rw-r--r-- | library/core/src/mem/mod.rs | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/library/core/src/mem/mod.rs b/library/core/src/mem/mod.rs index b810318fe7d..bf10ada0176 100644 --- a/library/core/src/mem/mod.rs +++ b/library/core/src/mem/mod.rs @@ -1132,10 +1132,12 @@ impl<T> fmt::Debug for Discriminant<T> { /// /// [Reference]: ../../reference/items/enumerations.html#custom-discriminant-values-for-fieldless-enumerations /// -/// The value of a [`Discriminant<T>`] is independent of any *lifetimes* in `T`. As such, reading -/// or writing a `Discriminant<Foo<'a>>` as a `Discriminant<Foo<'b>>` (whether via [`transmute`] or -/// otherwise) is always sound. Note that this is **not** true for other kinds of generic -/// parameters; `Discriminant<Foo<A>>` and `Discriminant<Foo<B>>` might be incompatible. +/// The value of a [`Discriminant<T>`] is independent of any *free lifetimes* in `T`. As such, +/// reading or writing a `Discriminant<Foo<'a>>` as a `Discriminant<Foo<'b>>` (whether via +/// [`transmute`] or otherwise) is always sound. Note that this is **not** true for other kinds +/// of generic parameters and for higher-ranked lifetimes; `Discriminant<Foo<A>>` and +/// `Discriminant<Foo<B>>` as well as `Discriminant<Bar<dyn for<'a> Trait<'a>>>` and +/// `Discriminant<Bar<dyn Trait<'static>>>` may be incompatible. /// /// # Examples /// |