Check for use of aria-hidden paired with hidden=until-found

[scottaohara]

ARIA in HTML is updating to indicate that the use of aria-hidden=true on an element that also has the hidden=until-found attribute needs to be treated as a MUST NOT author error.

Using both together means that someone could find the hidden content using a browser in-page search, but the revealed previously hidden content will now be visually hidden, but still inaccessible to people using AT.

e.g.,

<p hidden=until-found aria-hidden=true>some content</p>

[gezlemon]

Hi @scottaohara, apologies it's taken so long to get to this.

Is there a change required? The validator currently flags using aria-hidden=true along with the hidden attribute as invalid, which would include using hidden=until-found. Is a special case required for hidden=until-found?

[scottaohara]

the change here is that aria-hidden=true on just a hidden element is an author SHOULD NOT, where as this new update is a MUST NOT for the specific hidden attribute value.

just wanted to raise this in case a distinction wanted to be made. but if not, then we're good to go. thanks!

[gezlemon]

Thanks, @scottaohara I think that's worth distinguishing, so I've submitted a PR