A complex type's or attribute group's attribute-use set (flattened through
attributeGroup references) may not contain two distinct declarations with the
same name and namespace (ct-props-correct.4 / ag-props-correct.2), nor more than
one attribute whose type is or derives from xs:ID (ct-props-correct.5).
Declarations are deduplicated by the identity of their declaring node, so the
same declaration reached by two attribute-group paths (a diamond) is one use,
not a clash. Names carry their resolved namespace (form / attributeFormDefault
for locals, the prefix binding for refs), so a local attribute and a reference
to a same-local-name attribute in an imported namespace do not collide. The
check runs after named simple types are resolved, so a named user type derived
from xs:ID is recognized, not just the built-in and inline forms.
XSTS: invalid schemas accepted 505 to 495 (attQ008/009/012/013, attgD006/007/
009/017, ctM003/004 now rejected), no other bucket raised. An adversarial critic
caught a false positive on same-local-name-different-namespace (fixed by
resolving the ref namespace) and a missed named-user-ID type (fixed by ordering
the check after type resolution). Disclosed under-rejections: the set inherited
through extension is not composed in; a duplicate needing an unprefixed
reference with no default namespace is not detected.
Mihaela Mihaljevic
067f04184f