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Document DST parameters on std::marker::Sized

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This is for discoverability.  If someone wants to know what ?Sized means, then
Sized will be the only keyword they can use to search; so even though this is
technically a language matter, it makes sense to document it where it will be
looked for.
This commit is contained in:
Stefan O'Rear
2015-10-18 04:17:33 -07:00
parent 206af38e74
commit dc61d0f093
1 changed files with 11 additions and 0 deletions
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11
src/libcore/marker.rs
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@@ -36,6 +36,17 @@ impl<T> !Send for *const T { }
impl<T> !Send for *mut T { } impl<T> !Send for *mut T { }
/// Types with a constant size known at compile-time. /// Types with a constant size known at compile-time.
///
/// All type parameters which can be bounded have an implicit bound of `Sized`. The special syntax
/// `?Sized` can be used to remove this bound if it is not appropriate.
///
/// ```
/// struct Foo<T>(T);
/// struct Bar<T: ?Sized>(T);
///
/// // struct FooUse(Foo<[i32]>); // error: Sized is not implemented for [i32]
/// struct BarUse(Bar<[i32]>); // OK
/// ```
#[stable(feature = "rust1", since = "1.0.0")] #[stable(feature = "rust1", since = "1.0.0")]
#[lang = "sized"] #[lang = "sized"]
#[rustc_on_unimplemented = "`{Self}` does not have a constant size known at compile-time"] #[rustc_on_unimplemented = "`{Self}` does not have a constant size known at compile-time"]