{
  "iter_id": "0121-implicit-cutover",
  "date": "2026-06-01",
  "mode": "standard",
  "outcome": "PARTIAL",
  "tasks_total": 1,
  "tasks_completed": 0,
  "reloops_per_task": { "4": 0 },
  "review_loops_spec": 0,
  "review_loops_quality": 0,
  "blocked_reason": "worker-blocked",
  "corpus_files_mode_flipped_this_session": 6,
  "corpus_files_migrated_total": 280,
  "test_failures_remaining": 82,
  "test_failures_at_session_start": 96,
  "notes": "Continuation. Phase A Step 3 FINISHED: corpus linearity-clean (6 files own->borrow for read-only-heap/HOF params: std_list filter+fold predicate, bench_hof_pipeline, bench_latency_implicit loop/one_op/pin_root, rc_pin_recurse_implicit pin, rc_let_alias pin_aliased, floats_2_average sum_acc/count_acc; std_*_demo import std_list so its fix propagates). Must-fail fixtures (real_consume, c4_double_consume, 3 own_return_provenance) correctly stay RED (criterion 4). Fixed a real codegen index-panic (codegen lib.rs:1341/1494 + surface print.rs:406: param_modes[i] -> .get(i).unwrap_or(Own)) for synthesised fn-defs with empty param_modes (lambda thunks / local-rec lifts) — unblocked local_rec/nested_let_rec/poly_rec demos. Rewrote 2 obsolete linearity in-source tests to binary-model semantics. REMAINING BLOCKER: a real codegen double-free (segfault, exit 139) from the lit-sub-pattern desugar (core/desugar.rs:1221) x arm-close Iter-A drop (codegen/match_lower.rs:788): an (own ADT) param matched with a (Cons (pat-lit K) _) arm double-drops the tail because the lit `else`/fall_k re-matches the same scrutinee and each re-match arm-close drop fires on the same children. Latent pre-cutover (Implicit scrutinees skipped the drop, leaking); the cutover's Own scrutinees activate it. Gates ~7 list demos + cascading mono/rewrite tests. Needs RED-first codegen debugging (debug-skill class), NOT mechanical fixture work. Hash pins deliberately NOT reset (ordering: pins last, only after codegen correct, so the irreversible reset is not baked over a buggy state)."
}