Typealias extensions are not shown on its page, but the extensions tab is rendered

[IgnatBeresnev]

Context

Typealiases have their own dedicated pages since Dokka 1.9.0 (#2862). It's a relatively new enhancement, so this particular issue likely slipped unnoticed and we didn't think of this use case, but it's not necessarily regression.

Expected

The dedicated page should either contain extension functions for typealiases or it should not, but either way there should be no empty tabs. Either no extension and no tab, or extensions under a tab.

Actual

The Members & Extensions tab is rendered, but there's no content, so the tab is empty.

Screenshot

Reproducer

Generate documentation for the following code and visit the page for TypeAliasToMyClass.

typealias TypeAliasToMyClass = Unit

fun TypeAliasToMyClass.extension() {}

[IgnatBeresnev]

Update:

1. Discuss it with Ilya/Seva, see if there are any objections from stdlib; Send a poll to libraries team
2. It seems we can show extensions only, no members, so the tab should be renamed if possible

Possible confusion points:

• The users might think that this extension is only available for the typalias, but in reality you can also call it on the aliased class.

[CLOVIS-AI]

Hey! As a library author, I think having the ability to view extension functions declared on a typealias in its dedicated page would be very useful.

I often use type parameters and extension functions to restrict usage of some functionality to some specific situation, as described by the type parameter. Because this can become unwieldy quickly, I create typealiases for these situations. It would be great if users could open a typealias' page and immediately see all the functionality that typealias is responsible for.