Assertion required for property <constraint>

See - Part 1, 3.1.3 References to Element Declarations and Type Definitions

The assertions include the following rule from this section about the
'element' attribute of  <fault>, <input> and <output>:
Schema-0020. An element attribute information item MUST NOT refer to a
global xs:simpleType or xs:complexType definition.†

I think there's a similar assertion that needs to be captured in the next
paragraph:
A constraint attribute information item MUST NOT refer to a global
xs:element definition.

....although the text needs to be corrected to reflect that constraint is a
child element of <property>, not an attribute, and it's the QName within
<constraint> that must not refer to a global xs:element declaration.

regards,
John Kaputin