It’s not clear to me in the spec whether or not this should work. I think we need to either add support for this syntax or clear up the ambiguity in the spec. In either case, I think this would be better suited as a github issue to track this until it is addressed.
Feel free to make these types of topics GitHub issues to begin with. If it turns out to be a non-issue or user error, we can close it and it will stay in the issue archives for others to search against if they run into the same user error.