In 1232, Michael Kay notes:

The Data Model section 3.3.1.2 says that if an element is annotated with an
atomic type T, then the typed value of the element is an instance of T. If my
reasoning above is correct, then this statement isn't true: the typed value of
<e xsi:nil="true"/> can surely only be ().

If it remains true that the type of a nilled element is not (), then this
section needs to be updated to point out that it matches T? but not T.