A simpleContent restriction is (annotation?, (simpleType?, facet*),
(attribute|attributeGroup)*, anyAttribute?) and an extension is
(annotation?, (attribute|attributeGroup)*, anyAttribute?): no model group, no
facets/simpleType in an extension, attributes before a single anyAttribute. The
membership table admitted the names but not the order or the model-group ban, so
a model group inside simpleContent, a facet in an extension, a misordered facet
or attribute, or a second anyAttribute (the ctD family) was accepted.
The derivation's children are matched against the context's ordered slot model,
reusing the slot walk built for complexContent. The structure walk's
per-component dispatch is factored into a helper to keep its complexity bounded.
XSTS: invalid schemas accepted 594 to 580, valid schemas rejected held at 72,
instance buckets unchanged.
