RE: Referencing attributes

The WG discussed this 2007-03-28. It is tracked as bugzilla #4346.
http://www.w3.org/Bugs/Public/show_bug.cgi?id=4363

Conclusions:

There is no rule in the specification that forbids referring to attributes
in the http://www.w3.org/2001/XMLSchema-instance namespace.

However, as shown, schema document is not valid because it lacks an import.
The specification requires imports, which serve a dual purpose of
identifying the resource containing the schema definitions (unnecessary in
this case) and licensing the import of definitions from that namespace.

However, note that even if the schema were valid, it would be ineffective.
The rules in Validation Rule: Element Locally Valid (Complex Type) mean
that the attribute use settings such as default values will not have any
effect because they are not consulted for the attributes in the
http://www.w3.org/2001/XMLSchema-instance namespace.

For the WG

//Mary