Enforce `tabpanel` role on elements controlled by a `tab`

[TastyPi]

Product

axe-core

Feature Description

For an element with the tab role, aria-controls should refer to an element with the role tabpanel. This does not seem to be enforced by axe.

[WilcoFiers]

That seems reasonable. I would put that in the best practice category of things though. I don't think there's any problem if aria-controls points to a container of the tab. But as a rule of thumb it certainly makes sense. Perhaps axe-core should test this in the way ARIA describes it here:

https://www.w3.org/TR/wai-aria-1.2/#tabpanel
Authors SHOULD associate a tabpanel element with its tab, either by using the aria-controls attribute on the tab to reference the tab panel, or by using the aria-labelledby attribute on the tab panel to reference the tab.

That would mean two things:

1. If aria-controls is used, it most point to a tab
2. if aria-controls isn't used, the tab must have aria-labelledby, pointing back to the tabpanel.