[devin-ai-integration]

Summary

This is item 497. It pays S3's item 474 NEXT (a), the strict-lead carry that S3 handed to Row 19. It works on the flow side only and touches none of R12's producers.

FlowArm.openNest.h_lead's ε disjunct now also carries trailingPropertyRun sc.tokens = []. accum_step_flow's h_tuple open-lead conjunct carries the same fact.

-- before
(sp_br = sp_flow₂ ∧ (gapTail sc).leadFree = true)
-- after
(sp_br = sp_flow₂ ∧ (gapTail sc).leadFree = true ∧ trailingPropertyRun sc.tokens = [])

Effect on accum_step_flow_trace:

• A held run (GapRead.props' h_held : trailingPropertyRun sc.tokens ≠ []) refutes the ε disjunct.
• The lead is then the strict separation SSeparate n .flowIn sp_scan sp_br that openNestSeqProps / openNestMapProps ask for.
• So the old fourth disjunct, the held-run nested open [&a [b]], is deleted.
• That case now lands in the first disjunct with trace ev ++ ev_p. The conclusion has three disjuncts.

Size:

• StreamAccum.lean: 5 lines. Only the white arm of h_tuple needed a new term, trailingPropertyRun_eq_nil_of_sync h_sync. The props arm already returned Or.inl, and the two openNest producer sites build unchanged.
• TraceOf/FlowWalk.lean: about 18 lines.
• accum_step_flow_trace has no other consumer.

Rule 2: the existing P109 (iii) row holds on this tree: the run is never glued to the bracket (glued 0, spanning a line break 1).

Pins moved:

• GhostIndexCensus: the FlowArm.openNest[14].h_lead ε row text gains the new conjunct. The count stays 123.
• ValueLineOrigins: liteNodes 673507 → 674092. This is term size only.

Closure log: items 491–496 are declared as gaps, each claimed by an open PR (#311, #313, #312, #316, #315, #317). check-closure-log is green for 11..497.

Local battery:

• lake build: 1564 jobs, exit 0.
• All gates are green.
• hygiene: 11565 / 0 / 0.
• run-all-tests: 0.
• suiterunner: 869 / 0 / 151.
• eventscore: 347 / 358.
• adversarial: 62181 / 62181.
• Axioms: the standard three on accum_step_flow and accum_step_flow_trace, and propext on FlowArm.openNest.

Link to Devin session: https://nasa-jpl-demo.devinenterprise.com/sessions/12a32597e3554be1aeeb264f49263290
Open in Devin Desktop: https://nasa-jpl-demo.devinenterprise.com/desktop/session/12a32597e3554be1aeeb264f49263290?variant=devin
Requested by: @NicolasRouquette

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🟢 Devin Review found nothing to fix · View findings

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.