Change #1206403 had a related patch set uploaded (by Reedy; author: Reedy):

[mediawiki/extensions/WebAuthn@master] WebAuthnManageForm: Remove $module property and replace with @property

https://gerrit.wikimedia.org/r/1206403

Why is it empty union type rather than MediaWiki\Extension\WebAuthn\Module\WebAuthn (which implements IModule so that should be a valid case of covariance)?

I guess that's not how it works:

By default, properties are neither covariant nor contravariant, hence invariant. That is, their type may not change in a child class at all. The reason for that is "get" operations must be covariant, and "set" operations must be contravariant. The only way for a property to satisfy both requirements is to be invariant.

I guess OATHAuthOOUIHTMLForm should use generics in its phpdoc?

Change #1206403 merged by jenkins-bot:

[mediawiki/extensions/WebAuthn@master] WebAuthnManageForm: Remove $module property and replace with @property

https://gerrit.wikimedia.org/r/1206403