There are a couple of things missing in 9.1.1.6. Container-element overriding:

• first, we don't state that it is possible to omit the type-argument-index element if there is only one of them
• second, we should be more clear about what happens in the case of an error (throw a ValidationException)

Error cases:

• declaration on a non generic type
• non existing type argument index
• omitted type argument index while there are several type arguments
• declaring the same container element type twice