A model group may not contain itself (mg-props-correct.2), an attribute group
may not reference itself transitively (ag-props-correct.3), and a substitution
chain may not loop (e-props-correct.6).
The model-group check follows references only within a definition's own
compositor tree, stopping at element and type boundaries: a group referenced
inside an element's content is a recursive data structure (permitted), not the
group containing itself (particlesZ010, addB077). A reference is followed only
when it resolves to the schema's own target namespace; a group or attribute
group redefined in xs:redefine ends the chain (its single self-reference is the
legal redefinition).
XSTS: invalid schemas accepted 516 to 505 (attgC010/020/031, attgD015,
groupB012-015, addB180, xsd009.e, xsd010.e now rejected), no other bucket
raised. A genuine cycle introduced across two redefined definitions is a
disclosed under-rejection (an adversarial critic's only finding).
Mihaela Mihaljevic
7c059e1355