The doc page for [`std::array`](https://doc.rust-lang.org/nightly/std/primitive.array.html) says this: > Arrays dereference to slices (`[T]`), so their methods can be called on arrays. However, though this is true of `Vec<T>`, arrays in fact coerce via [`CoerceUnsized`](https://doc.rust-lang.org/std/ops/trait.CoerceUnsized.html), not via deref coercion.