<pre>
type T[P *C] …
type T[P (C)] …
type T[P *C|Q] …
…
</pre>

<p>
In these rare cases, the type parameter list is indistinguishable from an
expression and the type declaration is parsed as an array type declaration.
To resolve the ambiguity, embed the constraint in an
<a href="#Interface_types">interface</a> or use a trailing comma:
</p>

<pre>
type T[P interface{*C}] …
type T[P *C,] …

See [CVE-2021-32677](https://github.com/tiangolo/fastapi/security/advisories/GHSA-8h2j-cgx8-6xv7) for more details.