## `Sized`
The [`Sized`] trait indicates that the size of this type is known at compile-time; that is, it's not a [dynamically sized type].
-[Type parameters] are `Sized` by default, as are [associated types].
+[Type parameters] (except `Self` in traits) are `Sized` by default, as are [associated types].
`Sized` is always implemented automatically by the compiler, not by [implementation items].
These implicit `Sized` bounds may be relaxed by using the special `?Sized` bound.