A redefined model group whose body references itself expands, in the compiled
content model, to the original group it redefines. Two gaps let an ambiguity
created that way slip through the Unique Particle Attribution check (cos-nonambig).
The compositional determinism engine treated the self-reference as contributing
an empty decision set, so the original group's particles were invisible to the
overlap test. It now expands one level to the redefine base, exactly as the
instance content-model path does, so a particle the original contributes is seen.
The expansion only surfaces genuinely reachable items, so the decision sets stay
a subset of the true model: the check can catch a real ambiguity but never invent
one, holding the false-positive direction at zero.
Separately, the UPA check walked only the root document, so an ambiguity a root
redefine creates in a complex type that lives in an included document was never
evaluated. It now runs over every schema root in the composition under the shared
redefine-effective context, mirroring the existing cross-document top-level
declaration check.
Closes XSTS schN10 (a three-level redefine chain). XSTS invalid-schemas-accepted
11 -> 10, valid-schemas-rejected held at 0. Full suite 1609 tests green in debug
and release.
Mihaela Mihaljevic
3a6aad0eb2