The section in the RFC titled "Background: What is kindedness?" is the most concise and helpful description of higher-kinded types I've encountered anywhere, and I absolutely love the attitude expressed at several points:<p><pre><code> Kinds are often called 'the type of a type,' the exact sort of
unhelpful description that only makes sense to someone who already
understands what is being explained.
</code></pre>
and<p><pre><code> the term "type constructor" is an obscure piece of jargon from type
theory which most users cannot be expected to be familiar with.
</code></pre>
Any fear I had that this RFC was an expression of Rust evolving into an academic toy is greatly assuaged by this. This is supposed to be a systems programming language and it needs to stay amenable to people that think in terms of bits and bytes, not categories and type theory.