</p>

<p>
Interfaces that are not <a href="#Basic_interfaces">basic</a> may only be used as type
constraints, or as elements of other interfaces used as constraints.
They cannot be the types of values or variables, or components of other,
non-interface types.
</p>

<pre>
var x Float                     // illegal: Float is not a basic interface

var x interface{} = Float(nil)  // illegal

type Floatish struct {

This release adds support for [Trio](https://trio.readthedocs.io/en/stable/). ✨

It upgrades the version of Starlette to `0.15.0`, now based on [AnyIO](https://anyio.readthedocs.io/en/stable/), and the internal async components in **FastAPI** are now based on AnyIO as well, making it compatible with both **asyncio** and **Trio**.