XL-2 carrier: record lowering fixes since #12584; add ServiceModuleLowering

[gunbai-bot]

XL-2 carrier update (gunbc.compiler_frontend_program_status xl2_prerequisite_standing, its witness; the P5 rehearsal roster is derived from xl2_prerequisites_outstanding, so it keeps one cause per outstanding arm by construction).

Every SHA cited was checked as an ancestor of main.

Arm	Standing	Basis (the RFM row)
CaretSymbolOperandLowering	DELIVERED #12420 aa3b461	caret_symbol_has_no_lowered_form records its trigger REACHED by MQ-1 PR-2. The #12617 handoff (39a0093) is cited too. The literal's type is not claimed.
ElseLessIfStatementLowering	DELIVERED #12713 2e95e66 (after #12607 1021d9f)	The RFM records its trigger MET for the guard. The residue still refuses located and is qualified in the arm.
OptionalAccessorLocatedRefusal	OUTSTANDING	The RFM is still open on the binder-chain route. Records #12615 7f14427, #12725 3feb055 and #12754 414782c.
LoweringOccurrenceProjection	OUTSTANDING	Records #12598 077af24 and #12757 fbdfd65: every NameRoleNotYetRead row is gone and role_not_yet_read went from 399 to 0. The RFM has no trigger-met receipt. Also notes that 5 of 116 transport files still fail v2 parse (#12778, then classes B/C).
WildcardMatchArmResolution	DELIVERED (resolve grain, unchanged)	Adds #12597 6571276. The RFM is still open at the typed-pattern-carrier trigger.
QualifiedFieldTypeVisibility	DELIVERED (unchanged, #12033)	It was already delivered before #12598.
ServiceModuleLowering (new)	OUTSTANDING	Tracked by service_interface_member_has_no_carrier. Refusal at normalize (service_realization_unreachable) keeps these modules' references out of the census. Trigger: a typed operation-modifier and io wire-key/default carrier. No owner today.

Also DELIVERED on their RFM rows' own receipts (at the parent's request): AsCastOperandLowering #12315 696a77d (trigger MET; refinement-cast residue on infer stays refused, typed), LambdaArgumentValueLowering #12210 c2c064f (row records CLIMBED; generic-Arrow emission is residue outside the class).

ListLiteralElementVisibility is DELIVERED by #12208 575fc48 on the canonical RFM list_literal_has_no_lowered_form (CLIMBED); the stale duplicate RFM list_literal_elements_dropped_at_v2_body_lowering is deleted (review 5369451225).

Partition: 24 arms, 21 delivered and 3 outstanding (OptionalAccessorLocatedRefusal, LoweringOccurrenceProjection, ServiceModuleLowering). XL-2 stays NotDerivable. The nesting-ruling wording is untouched.

🤖 Generated with Claude Code

[briansrls]

HOLD / REQUEST_CHANGES at exact head 45d33bb.

[P1] ListLiteralElementVisibility is already delivered, so the proposed 20-delivered / 4-outstanding partition and the P5 roster derived from it are wrong.

The landed receipt is gunbc#12208, merge 575fc486add332a5f5cce866a9338520c9192361, which is an ancestor of this PR's base. Its exact contract is the capability this arm names: one body_lower_list_literal producer reached from body_lower_primary_expr through the shared value reader on call-argument, data-initializer, let-value, operand and scrutinee routes; every element lowers whole, and an unreadable element refuses located. That implementation is present at this exact head. The canonical RFM list_literal_has_no_lowered_form explicitly records CLIMBED BY gunbc#12208, with production-route shape, resolve and reference-conservation evidence.

The carrier instead follows the stale duplicate RFM list_literal_elements_dropped_at_v2_body_lowering, whose receipts still claim body_lower_primary_expr answers [a] with [ and that no fix has merged. That contradicts both the live compiler and the canonical RFM. It also leaves the CompoundCallArgumentValueLowering qualification falsely saying a list-valued argument still refuses at the list.

Bounded correction:

• make ListLiteralElementVisibility PrerequisiteDelivered with gunbc#12208 / 575fc486ad and qualification matching the canonical RFM;
• change the partition and witness to 24 = 21 delivered / 3 outstanding (OptionalAccessorLocatedRefusal, LoweringOccurrenceProjection, ServiceModuleLowering), and change the XL-2 NotDerivable control's delivered count to 21;
• remove the list-literal row from xl2_prerequisites_outstanding(), which removes its spurious rehearsal/P5 cause;
• reconcile the two list-literal RFMs, preferably deleting or retiring the stale duplicate rather than leaving two contradictory authorities; and correct the stale compound-call qualification.

The other delivered flips, residue qualifications, three genuinely outstanding arms, new service-module arm, derived rehearsal wiring, unchanged nesting ruling and exact-head checks otherwise look coherent. Return with the corrected exact head for merge-queue-only review; require the actual merge_group candidate to pass, with no direct merge or check bypass.

[briansrls]

APPROVE-MERGE at exact head ab71a1b. This supersedes CHANGES_REQUESTED review 5369451225.

The blocker is resolved: ListLiteralElementVisibility is delivered by gunbc#12208 / 575fc48 with the canonical list_literal_has_no_lowered_form CLIMBED receipt and the discriminating list-literal truncation owner. The stale duplicate RFM is deleted, its remaining prose citation is repointed, and CompoundCallArgumentValueLowering no longer claims list/lambda/caret values remain refused.

The carrier and witness now agree on 24 prerequisites = 21 delivered / 3 outstanding: OptionalAccessorLocatedRefusal, LoweringOccurrenceProjection, and ServiceModuleLowering. The NotDerivable control derives 21 delivered. The rehearsal/P5 refusal roster remains derived from xl2_prerequisites_outstanding(), so moving ListLiteral to Delivered removes its cause without a second roster edit. Current main is merged.

No findings. Merge queue only: require all exact-head checks and the actual merge_group candidate to pass against then-current main; no direct merge or check bypass. A later #12780 carrier update is a separate post-landing delta and is not a condition on this exact head.