One forward iteration; main never rewound. 1ff7e81 (the pre-9973546
commit) is the per-region byte oracle — every reverted source/test
file is byte-identical to it; crates/ailang-check/src/lib.rs fully so.
Root cause being corrected: the Iteration-discipline milestone was an
over-escalation of fieldtest finding F1 (a [friction] item whose own
minimal recommendation was a DESIGN.md note). Its totality dichotomy
made the maximally-LLM-natural build(d:Int)=Node(1,build(d-1),
build(d-1)) inexpressible (it.3 BLOCKED); the only in-thesis escape
(A1/it.2b) conceded the language's first documented-unenforced
totality precondition — a purity-pillar dilution the user rejected in
favour of a full revert + rebuild.
Removed: Term::Loop/Term::Recur/LoopBinder; the verify_structural_
recursion guardedness pass + term_contains_loop + Diverge-injection +
the transitively-it.2 module_fns plumbing; the five Recur*/
NonStructuralRecursion CheckError variants (+ code() + the 3 dedicated
ctx() arms); the it.1 codegen loop-header/phi/back-edge + parallel
block_terminated setter; all Loop/Recur walker arms; 16 it.1/it.2
fixtures; 2 pin files; bench/it3-oracle/. Restored: 2 RC fixtures to
1ff7e81 content.
Surgically kept (not in 1ff7e81, landed with the milestone but
independently sound): feature-acceptance clause 3 in DESIGN.md and
skills/brainstorm/SKILL.md, with its worked example de-claimed from
"shipped" to hypothetical-illustration form; the F3 P2 todo.
bench/orchestrator-stats/2026-05-15-iter-it.{1,2,3}.json kept as
historical record (like journals/plans).
Sole net addition: an honest F1/F4 documented-idiom note in DESIGN.md
(the tail-recursive accumulator fallback; examples/mut_counter.ail),
guarded by a doc-presence test — "a documentation note is not a
reshape", asserts nothing at the typecheck level.
Roadmap: the Iteration-discipline block + blocking-fork section
removed; the genuine total-Int-recursion ambition preserved as a
deferred P2 milestone sequenced behind a future Nat/refinement-types
milestone (not abandoned — correctly sequenced after the type
machinery it needs). 2026-05-15-iteration-discipline.md carries a
superseded header; it.1/it.2/it.3 journals + plans stay as history.
Correctness gate PRISTINE: 164 surviving 1ff7e81-era fixtures
ail check/ail run byte-identical to pre-milestone behaviour (verified
against a 1ff7e81 worktree reference compiler, zero drift);
cargo test --workspace 600/0; zero residual it.1/it.2 production
surface.
Spec docs/specs/2026-05-16-iteration-discipline-revert.md (b3853bf),
plan docs/plans/2026-05-16-iter-revert.md (abf0013).
Two HEAD-vs-spec defects the it.3 recon found, fixed at the spec:
(1) "remove is_false" was wrong — is_false is shared with
WorkspaceDef.drop_iterative; it survives, doc re-scoped only.
(2) "remove the Decision-3 Diverge line" struck — it.2 already
rewrote Decision 3 to make Diverge the real effect (the milestone's
payload); it.3 touches Decision 8 only.
(3) The codegen-rework bullet under-described the real risk: the
18g.1 pre-tail-call husk-dec (match_lower.rs:658-736) reads
Term::App{tail:true} directly, protects the 18f.2 RC-RSS pin, and
its field-forced deletion is RC-safe ONLY if it.1 loop codegen
drops superseded owned binders across recur — unverified. Spec now
names this as the load-bearing it.3 risk with a RED-gated
verification + a named remediation (owned-loop-binder-drop-on-recur
in scope for it.3). Only 3 (not 7) setters are tail-driven.
No design decision (D1-D4) changes; design validated by shipped
it.1/it.2. Not relitigating shipped work (spec_over_plan_patches).
The original spec premise "21 .ail fixtures / 34 (tail-app …) sites"
under-counted the corpus's non-structural-recursion surface. it.2
proved the true it.3 migration set is three classes: the ~20
tail-app-marked fixtures + ~18 no-ADT-candidate counter-recursion
fixtures (deferred via it.2's no-candidate skip) + the 2 RC fixtures
it.2 joined to the transitional grandfather. it.3 removes the
tail==false grandfather AND the no-ADT-candidate skip together.
No design decision (D1-D4) changes — factual scope-widening only,
traceable to 2026-05-15-iter-it.2.md §Concerns. Not relitigating
the complete, green it.2 (feedback: spec_over_plan_patches — fix
the spec where it governs, not the plan around it).
User-approved 2026-05-15 (read, probed via the sma_factory.myc streaming
analysis, no D1/D2 change requested, proceed-by-/boss). Grounding-check
PASS holds: spec bytes unchanged since the Step 7.5 dispatch (the
non-load-bearing "34 vs 36 tail-app sites" wording left as attested
rather than re-grounding for a count the agent ruled non-defect; the
21-fixture migration unit is exact). Three ordered iterations: it.1
loop/recur additive, it.2 guardedness checker + Diverge effect, it.3
tail-app/tail-do retirement + corpus migration.
Brummel