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| -rw-r--r-- | src/libcore/marker.rs | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/libcore/marker.rs b/src/libcore/marker.rs index f9480b4349d..27d8af2e8a8 100644 --- a/src/libcore/marker.rs +++ b/src/libcore/marker.rs @@ -36,6 +36,17 @@ impl<T> !Send for *const T { } impl<T> !Send for *mut T { } /// 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")] #[lang = "sized"] #[rustc_on_unimplemented = "`{Self}` does not have a constant size known at compile-time"] |