AILang/docs/journals/2026-05-18-audit-prose-loop-binders.md

audit prose-loop-binders — Milestone-prose-loop-binders tidy (clean)

Date: 2026-05-18 Milestone: prose-loop-binders (single-iteration) Commit range: 6cbd0fe..c9355d7 (prev close = loop/recur at 6cbd0fe) Status: CLOSED — clean, carry-on (no fix, no ratify)

Step 1 — Architect drift review

ailang-architect over 6cbd0fe..HEAD: clean, zero drift, zero debt. Verified against the diff (not journal trust):

• Single hunk in crates/ailang-prose/src/lib.rs (the Term::Loop arm of write_term, lines 936–953). The two non-render Term::Loop sites (count_free_var, subst_var_with_term) and all Term::Recur arms are absent from the diff — untouched.
• DESIGN.md and PROSE_ROUNDTRIP.md make no claim about how prose renders loop (grep: no match), so the spec's "no doc edit needed" is correct, not a skipped obligation. DESIGN.md:714 loop(n-1) is an ordinary recursive-call illustration in Decision 8, unrelated to the Term::Loop construct — not stale.
• Diff touches only the four named code/fixture files plus expected docs (spec/plan/journal/INDEX/roadmap/stats). No carve-out / hash-pin / round-trip lockstep bypassed (prose is off the Form-A↔JSON round-trip path by construction).
• The architect_sweeps.sh Sweep-1 DESIGN.md hits all pre-date 6cbd0fe and are outside this milestone's diff (zero DESIGN.md lines changed) — flagged for the record, not attributable here.

Architect recommendation: carry on as planned.

Step 2 — Bench-regression check

• bench/compile_check.py → exit 0, 24 metrics, 0 regressed.
• bench/cross_lang.py → exit 0, 25 metrics, 0 regressed. Notably its independent bench_list_sum.ail_bump_s reads +1.50% (±15% tol) → ok — corroborates that check.py's bump_s firing is baseline-staleness, not a real bump regression.
• bench/check.py → exit 1. First run: 3 regressed (bench_list_sum.bump_s +13.17%; latency.implicit_at_rc.p99_9_us +37.30%; latency.implicit_at_rc.max_us +114.14%), 4 improved, 56 stable. Confirmatory identical re-run (no code change): p99_9_us +10.22% → ok, max_us +22.17% → ok (median and p99 within tol on both runs) — the two latency-tail firings were single-sample 5-run RC-mode jitter, proven by re-run. bench_list_sum.bump_s persisted at +11.79% (consistent with the +13.17% first run): summary 63 metrics; 1 regressed.

Step 3 — Classification

Item	Class	Rationale
Architect drift	carry-on	clean — nothing actionable
throughput.bench_list_sum.bump_s +~12%	carry-on	The already-tracked P2 roadmap todo "*.bump_s throughput baseline is stale vs current hardware" — byte-oracle-proven environmental (not codegen) at the 2026-05-16 iteration-discipline-revert audit. Causally impossible to attribute to a projection-only ailang-prose change (prose is not in the bench runtime path; architect verified the diff is one render-arm + test fixtures).
latency.implicit_at_rc p99.9 / max	carry-on	Single-sample 5-run RC-mode tail jitter; vanished on identical re-run with median/p99 always within tolerance. Not a regression; the queued P3 "latency methodology rework" (histogram-based) exists precisely to de-noise this metric family.

Step 4 — Resolution

Carry-on on every item. No fix iteration, no baseline ratify.

Explicitly not ratified: the *.bump_s baseline is NOT bumped here. The P2 roadmap todo scopes a holistic recapture+recalibration of the entire *.bump_s set on current hardware from a known-clean commit as a dedicated bench-harness iteration; opportunistically bumping one metric's baseline inside an unrelated projection-only milestone is exactly the "bump the baseline, the regression is expected" rationalisation the audit Iron Law forbids, and would fragment the recapture the P2 todo owns. The pointer stands; the todo is unchanged.

Fieldtest applicability

Not applicable / not dispatched. fieldtest is Boss-dispatched for a milestone that touched the authoring surface — the fieldtester writes .ail Form-A programs and runs them through the public ail CLI. This milestone changed only the Form-B reading projection (ail prose output); the Form-A authoring surface, the typechecker, codegen, and runtime are byte-unchanged. A fieldtester authoring .ail programs would not exercise the prose-render change at all — there is no friction/bug/spec-gap axis for it to probe. The two committed whole-file byte-equality .prose.txt snapshots + the live-CLI ail prose | diff acceptance checks (iter journal) are the end-to-end gate for a projection-only milestone.

Milestone close

The prose-loop-binders milestone is CLOSED, clean. Architect drift clear; bench carry-on (sole persistent firing is the tracked P2 *.bump_s environmental staleness, latency-tail proven sampling noise by re-run). Roadmap P0 entry flipped to closed; no follow-up iteration spawned.