A constraining facet must apply to its simple type's variety (XSD 1.0 Part 2):
a list may be constrained only by length/minLength/maxLength, pattern,
enumeration, whiteSpace; a union only by pattern and enumeration. A value-bound
facet (maxInclusive, totalDigits, ...) constrains an atomic value space, so
restricting a list of integer by maxInclusive was wrongly accepted.
The base's variety is resolved from the raw tree (this runs before the types
are compiled), namespace-aware so a user type sharing a built-in's local name
does not flip the variety: a base in the XSD namespace is a built-in (only the
list datatypes are list-variety), a base in the schema's own target namespace
resolves to a declared global, and an external or unresolvable base is skipped.
XSTS: invalid schemas accepted 664 to 638, valid schemas rejected held at 72,
instance buckets unchanged.