aria-labelledby - chaining vs nesting

Bryan,

 

You previously wrote:

 

1.           The aria-labelledby referrals can only be followed once, and
not on any subsequent elements if encountered there such as by chaining
aria-labelledby attributes together on different elements. Only the first
will be followed and no others.

2.           You cannot nest aria-labelledby references, where you have
aria-labelledby on the root node as well as on a child node of the root
node. In this last case, only the root node will be traversed and none of
the child nodes will be parsed.

 

Since child nodes are only processed if the root node supports name from
content, and since aria-labelledby overrides name from content, the only way
I can see that a child node with aria-labelledby could be part of the
calculation is by chaining, e.g.:

 

<h1 aria-labelledby="child-span"><span id="child-span"
aria-labelledby="other-span"></span></h1>

 

In this case, the aria-labelledby attributes are chained as well as nested.

Is there a scenario where you could have nesting without chaining?

 

I'm just trying to determine if we need warnings against both in the
guidance, or if it is sufficient to explain that chaining is prohibited.

 

Thanks