A block on a substitution-group head's TYPE (its {prohibited substitutions}), not
only on the head element, bars a member whose type reaches the head's type by the
blocked derivation method. filterSubstitutions consulted only the head element's
own block, so block="restriction" on the head's complex type let a
restriction-derived member substitute.
The substitution-group filter now drops a member when its derivation method to the
head's type is in the union of the head element's {disallowed substitutions} and
the head type's {prohibited substitutions}. The element-level block="substitution"
outright bar stays element-only (a type's prohibited-substitutions never carries
substitution), and a member derived by a method the block does not list still
substitutes.
invalid-instances-accepted 53 to 50, no false positive (valid-instances-rejected
and valid-schemas-rejected held at 0). An adversarial review confirmed members
derived by an allowed method, the positive disallowedSubst instances, transitive
chains, and blockDefault interactions all still substitute. (A separate
cross-document cross-namespace substitution-group rejection was confirmed
pre-existing on HEAD, not introduced here.)
Mihaela Mihaljevic
75bb89dac7