XL-2 carrier: wildcard arm delivered at resolve grain, QualifiedFieldTypeVisibility outstanding, accessor partial evidence

[gunbai-bot]

WildcardMatchArmResolution -> DELIVERED by #12297 (0579afa) at RESOLVE
grain; no lowered wildcard form exists and the RFM stays open.
QualifiedFieldTypeVisibility added OUTSTANDING, tracked by
a_qualified_field_type_mention_is_absent_from_the_census_today.
OptionalAccessorLocatedRefusal stays OUTSTANDING with #12245 (56f13fc)
recorded as partial evidence. Partition witness: 19 arms, 11 delivered,
8 outstanding. P5's roster derives from xl2_prerequisites_outstanding, so it
stays one cause per outstanding arm; XL-2 stays NotDerivable.

Co-Authored-By: Claude Opus 5.5 (1M context) noreply@anthropic.com

Witnesses not run locally: remote runners refuse with HostBudgetUnreadable, so CI floor is the evidence.

🤖 Generated with Claude Code

[briansrls]

APPROVE at exact head 7880b55, for merge-queue landing.

This is the carrier follow-up required after #12297. WildcardMatchArmResolution is delivered only at resolve grain: no spurious '_' unbound-reference residual, not a distinct lowered wildcard form, and the original RFM remains OPEN. QualifiedFieldTypeVisibility is admitted as an explicit OUTSTANDING prerequisite rather than remaining outside the carrier's universe. OptionalAccessorLocatedRefusal remains OUTSTANDING with #12245 only partial evidence.

The code updates the enum/roster/label/evidence consistently, and the partition witness checks named membership and uniqueness as well as the 19 = 11 delivered + 8 outstanding partition. P5 consumes the outstanding roster; XL-2 remains NotDerivable. There is no premature whole-milestone completion here.

I reviewed the two-file patch and inspected exact-head Actions run 36176329247: all five jobs succeeded. The PR is honest that local execution was blocked by HostBudgetUnreadable; I did not run the witnesses locally either.

Require the actual merge_group candidate to pass against then-current main, including integration with the other compiler_frontend_program_status edits. No direct merge or bypasses.