pub unsafe trait Tag: Copy { }Expand description
A type suitable for tagging length, indices, and containers.
Safety
The manner in which new ExactSize instances of types implementing this trait can be created
is an invariant of each individual type. It must not be allowed to subvert the invariants
imposed by any other type implementing this trait. In particular you mustn’t create an instance
that allows coercing a ExactSize<ATag> into ExactSize<BTag> where you don’t control both
these types. Note that this restriction MUST hold for every possible coercion allowed by the
language. There are no inherently safe constructors for ExactSize but each tag type might
define some.
The type must further promise to be zero-sized and have an alignment of exactly 1. This
allows tags to be virtually added to other referenced objects in-place.
Object Safety§
Implementors§
impl Tag for Generative<'_>
SAFETY: This is invariant over the lifetime. There are no other coercions. See https://doc.rust-lang.org/nomicon/coercions.html#coercions