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Author SHA1 Message Date
Brummel d72fe0c2e6 fix(codegen): drop branch-consume-split owned params (#63 leg 3)
The last leg of the #63 drop-soundness cluster: an (own ...) heap param
consumed on one match-arm / if-branch but live on a sibling was never
dropped on the live path, leaking one slab per call. This was the
residual live=2 leak in series_sma that kept the series headline from
being leak-clean.

Root: the per-fn aggregate consume_count (the worst-case max over all
branches from uniqueness::merge_states) was codegen's only consume
signal, and every owned-param drop site gated on it. A param consumed
on SOME branch makes the aggregate >= 1, so every site skipped it —
including the branch where it stays live. match and if share this root
(if is first-class MTerm::If, not desugared to match).

Mechanism (spec 0068):
- CAPTURE: uniqueness retains the per-branch consume snapshots it
  already computes per branch and discarded at the max merge — new
  BranchConsume + infer_module_with_cross_branches (the aggregate-only
  infer_module_with_cross now delegates and drops the channel).
- CARRY: additive MArm.consume / MTerm::If.{then,else}_consume, attached
  by lower_to_mir via a traversal-order cursor (post-order pop, kind- and
  exhaustion-asserts make a desync a loud panic; neutral for const bodies
  which uniqueness does not walk). The AST carries no node id, so the
  correspondence is the structural pre-order both walks share — pinned by
  branch_consume_maps_attach_to_matching_arms.
- GATE: emit_leakclass_branch_param_drops fires a fall-through drop only
  for the leak class (branch_consume==0 AND aggregate>=1), in match arms
  + both if branches; the pre-tail-call dec switches its gate source from
  the aggregate to per-arm. The fn-return dec and arm-close pattern-binder
  dec are UNCHANGED.

Safety:
- Double-free: the drop sites partition by aggregate (==0 -> existing
  fn-return/pre-tail-call; >=1 -> new per-branch). Disjoint, so no param
  is dropped twice — no fn-return disable, no tail-position analysis.
- Use-after-free: the checker rejects use-after-consume, so an
  aggregate>=1 param is provably dead past the construct (path-terminal
  drop, tail position irrelevant).
- Type eligibility (found by the full-suite gate during implement; spec
  0068 refined): the new agg>=1 site is the FIRST drop site that can
  reach a STATIC closure-pair param (a top-level fn ref like inc in
  Either.either, consumed on one arm, live on the other) — a .rodata
  constant with no rc-header. field_drop_call routes Type::Fn / static-Str
  / Type::Var to the bare ailang_rc_dec, which underflowed on it. The
  helper now drops only params with a real per-type heap-ADT drop fn
  (field_drop_call != "ailang_rc_dec"). Sound (no underflow) and
  leak-correct (a static closure/Str allocates nothing). Witnessed green
  by std_either_demo / std_list_demo / poly_rec_capture_demo.

Verification: full workspace suite green (116 binaries); both new leak
pins (if + match) and series_sma_no_leak_pin green at live=0; legs 1/2
pins still green; INTERCEPTS<->(intrinsic) bijection intact; no
Pattern::Lit reject path added.

The leg-3 helper's type precondition was applied inline by the
orchestrator (a narrowing guard clause in an already-reviewed Task-4
helper, full context loaded) after the implement-orchestrator correctly
surfaced the spec gap rather than papering over the regression.

This clears the series_sma leak tail; the series milestone (#61) close
stays a separate deliberate step (its end-to-end milestone fieldtest).

closes #63
2026-06-02 15:47:01 +02:00
Brummel 6bc0b501cb feat(codegen): relocate per-binder consume_count into MIR; delete codegen's second uniqueness run (mir.3a)
First of two iterations delivering spec 0060's mir.3 row (plan
docs/plans/0117-mir.3a-consume-count-relocation.md). The per-binder
consume_count — the only thing codegen read from its second
infer_module_with_cross run — now lives on a new binder-keyed
MirDef.consume: BTreeMap<String,u32>, filled once by lower_to_mir on the
post-mono body. Codegen builds its existing (def,binder)->consume_count
lookup from those maps and the three scope-close drop sites (own-param,
let-binder, match-arm) read it; the codegen uniqueness run, its
UniquenessTable field, and the import are deleted.

mir.3 is split into two iterations (recorded in spec 0060): the named
deletion depends ONLY on consume_count. All three drop sites read
consume_count from self.uniqueness, while the modes they also gate on
(param_modes for the own-param dec, scrutinee_is_owned for the match
dec) come from the type, not the uniqueness pass (UniquenessInfo carries
no mode). So mir.3a relocates consume_count and ships the deletion;
mir.3b (next) fills MArg.mode/MTerm::Let.mode and switches emit_call's
anon-temp gate onto MArg.mode. The split halves the change at the
codebase's highest-risk surface (RC/drop correctness, the raw-buf leak
saga) and makes each half independently verifiable against the live=0
leak pins.

Design: consume_count lands on MirDef (binder-keyed), NOT on MArg. The
drop sites key by (def, binder_name) — a per-binder aggregate — while the
spec-sketched MArg.consume_count is per-arg-position and never reaches
them; the per-def map matches the UniquenessTable's own keying and all
three binder kinds (param/let/pattern) uniformly. MArg.consume_count
stays a mir.1 default. Source = run check's infer_module_with_cross
inside lower_to_mir post-mono (the synth_pure single-engine-re-walked
pattern); retaining a check-time result is blocked (check's uniqueness
is pre-mono and runs on-demand-from-codegen, never in check_workspace,
so it would miss the mono specialisations). cross_module_types
(= codegen's module_def_ail_types) is rebuilt in elaborate_workspace
from the post-mono workspace.

Safety property held: this is a PURE RELOCATION of an identical
computation — infer_module_with_cross ran on the post-mono module in
codegen and now runs on the same post-mono module in lower_to_mir, so
drop placement is byte-identical. cross_module_types matches
module_def_ail_types exactly (both insert f.name->f.ty over post-mono
Def::Fn), confirmed by the leak pins staying green.

Verification (orchestrator, post-implement inspect): diff matches the
plan; codegen grep-clean for infer_module_with_cross + UniquenessTable
(now ailang-check-internal); cargo build --workspace clean (no errors,
no unused warnings — module_def_ail_types survives for emit_call's
anon-temp param_modes gate); cargo test --workspace 701 passed / 0
failed / 3 ignored (+1 = the new producer pin
mirdef_consume_is_populated_for_let_binder; no #[ignore] added). The
live=0 drop-correctness witnesses all green:
alloc_rc_loop_valued_rawbuf_binder_drops_at_scope_close (#43/#47),
alloc_rc_heap_loop_binder_replaced_by_recur_does_not_leak,
alloc_rc_print_int_does_not_leak_show_result_str. #49 stays #[ignore]
(mir.4); #51/#53 build guards green.
2026-05-31 19:48:57 +02:00
Brummel a6fd93adba feat(codegen): pre-resolve the App callee in MIR; delete is_static_callee + type_home_module (mir.2)
Second re-deriver removal of the typed-MIR milestone (spec
docs/specs/0060-typed-mir.md, plan docs/plans/0116-mir.2-callee-static.md).
Static-callee resolution moves out of codegen and into lower_to_mir:
every Term::App callee is classified once, mirroring check's own synth
Term::Var ladder (lib.rs:3409-3582), and emitted as a resolved Callee.
Codegen reads the callee identity off MIR and routes each kind to the
right lowering. The codegen re-derivers is_static_callee and
type_home_module are deleted, and the lower_app <-> is_static_callee
lockstep pair is struck from CLAUDE.md.

Callee reshape (beyond the spec's original {module, fn_name} sketch —
spec 0060's Concrete-code-shapes block is updated in this iteration):

  pub enum Callee {
      Static  { module, fn_name, sig: Type },  // user/prelude fn -> emit_call, module pre-resolved
      Builtin { name, sig: Type },             // operator/intrinsic -> inline opcode lowering
      Indirect(Box<MTerm>),                    // dynamic: fn-pointer / closure / shadowed name
  }

Two forced refinements, both settled in planning:

- sig:Type on each resolved variant. drop::synth_callee_ret_mode reads
  the callee ret_mode, today off Callee::Indirect(inner).ty(). A
  resolved callee has no sub-term, so the sig (= synth_pure(callee),
  mode-preserving) is the lossless replacement. This is NOT a mir.3
  pull-forward: the MArg param-mode / consume_count fields stay at their
  mir.1 defaults. Without it, every statically-resolved call would lose
  its drop signal and the RawBuf / int_to_str RC-stats pins mir.1b fixed
  would regress.

- Builtin variant. Operators and the str-num builtins (+, not,
  str_concat, ...) are lowered inline by name and have no module/fn_name;
  a separate variant is cleaner than a sentinel module. The classifier
  decides Builtin vs Static from CHECK'S OWN resolution (a name in
  env.globals with no owning module is a builtin), never a copy of
  codegen's old is_static_callee allowlist. The recon's divergence audit
  confirmed check's builtin set and codegen's inline-arm set match
  exactly, so the single-engine rule is mechanically satisfiable with no
  env threading gap.

type_home_module is fully deletable: a workspace-wide grep confirmed no
program references a type-scoped T.fn as a value, so its only other
consumer (resolve_top_level_fn) collapses to the module-name fallback
with no behaviour change. (The spec's "x3 mirrors" wording over-counted;
the live surface was the definition plus two call sites.)

Alternatives rejected during planning: sentinel module in Static
(ugly); builtins left as Indirect (breaks — no fn-pointer for an
operator); name-rewrite Static{name,sig} keeping lower_app's by-name
dispatch (blurs builtin/user and still needs sig). The mir.1b
re-synth-strictness trap (post-mono synth_pure re-unify surfacing
mode-strip / bare-vs-qualified / metavar leaks) did NOT fire under the
new producer path — qualify_local_types mode-preservation and the $u
wildcard normalisation from mir.1b held.

Verification (orchestrator, post-implement inspect): diff matches the
plan; grep-clean for is_static_callee + type_home_module across
ailang-codegen and ail; cargo build --workspace green; cargo test
--workspace 700 passed / 0 failed / 3 ignored (no #[ignore] added this
iteration — the 3 are the pre-existing #49 Str-leg pin + two doctests).
Acceptance witnesses green: #53 (mono_new_over_user_adt_builds_and_runs),
#51 (rawbuf_new_int_size_only_builds_and_runs still builds), show_print
cross-module (print_user_adt_runs_end_to_end), the new mir.2 pins
(mir2_resolved_callee_kinds_run_end_to_end, callee_classification_*,
strengthened new_over_user_adt_carries_node_types asserting Callee::Static).
#49 heap-Str loop binder stays #[ignore] (lifts at mir.4).

Two new examples/ fixtures back the new pins (classify_pin.ail for the
producer classification pin, mir2_callee_kinds.ail for the E2E),
ail-parse / round-trip clean.

Forward note (cycle-close architect): crates/ail/tests/codegen_import_map_fallback_pin.rs:14-15
doc prose names lower_app's cross-module arm and synth_with_extras as
failure-mode targets — both now deleted (mir.2 / mir.1b). The pin's
protected invariant is still valid and green; the prose is stale and
wants a doc-honesty reword, left out of this iteration's footprint.
2026-05-31 19:27:56 +02:00
Brummel 600565d356 fix(check): localize own-ADT type-args in free-fn mono; complete the lower_to_mir producer
Additive producer-side work for the typed-MIR milestone (spec
docs/specs/0060-typed-mir.md), surfaced while building the mir.1b
codegen-consumption switch. Nothing here consumes MIR — codegen is
untouched; the whole existing suite stays green and one new RED pin
goes green. The mir.1b codegen switch itself stays in the working tree.

Headline fix — own-ADT type-arg localization in free-fn mono:

  monomorphise_workspace's free-fn arm normalises every observed
  type-arg through Registry::normalize_type_for_lookup. That
  normalisation is load-bearing for cross-module dedup and a stable
  specialisation symbol name, but it qualifies a *defining-module-own*
  ADT to `<module>.<T>`. synthesise_mono_fn_for_free_fn then substitutes
  those qualified type-args into the polymorphic source signature and
  body, which are in the module's own *bare* convention (the qualify
  pre-pass deliberately leaves own-module type-cons bare — lib.rs:4358,
  "the current module sees its own types bare"). The result is a
  self-inconsistent specialisation: e.g. fold_left specialised with
  accumulator b := List<Int> minted
    ((std_list.List<Int>, Int) -> std_list.List<Int>,
     std_list.List<Int>, List<Int>) -> std_list.List<Int>
  — a qualified accumulator parameter against a bare list argument and a
  bare Lam body. check_workspace never hits this (it synths the pre-mono
  bodies, bare throughout); the old codegen tolerated it via the
  now-deleted synth_arg_type's loose type-tracking. The post-mono synth
  re-entry in lower_to_mir does full unification and correctly rejects
  it: `expected std_list.List<Int>, got List<Int>`.

  Fix: localize_own_types (mono.rs) strips the `<defining_module>.`
  prefix back to bare for the module's own ADTs, applied to the type-args
  before they are substituted, so the synthesised signature and body stay
  uniformly bare-own. The *stored* type_args remain normalised, so the
  symbol name and the Phase-3 rewrite-cursor key on the same canonical
  form — the byte-identity invariant between synthesis and rewrite is
  untouched. The ClassMethod arm needs no analogue: it already
  substitutes the un-normalised target.type_ (mono.rs:841).

  Alternatives rejected: (a) drop the normalisation in the shared
  apply_subst_and_normalize helper — breaks cross-module dedup, mints
  duplicate specialisations under divergent names. (b) Make
  lower_to_mir's synth treat `<owner>.T` and bare `T` as equal during
  unification — papers over the producer inconsistency in the consumer
  and contradicts the established own-types-stay-bare invariant the rest
  of check relies on. (c) Qualify the whole synthesised def own->qualified
  — fights lib.rs:4358 and would require the lower path to also flip,
  cascading the convention change through synth.

Producer completeness (additive, mirrors existing guards):

  - lower_module skips Type::Forall defs (lower_to_mir.rs), mirroring
    emit_module's guard. Polymorphic defs are stale source kept for
    round-trip; their bodies carry mono-rewritten call names for
    specialisations that were never synthesised, so a synth re-entry
    would hit UnknownIdentifier.
  - lower_module lowers non-literal const bodies to typed MTerm, carried
    in MirModule.consts (+ MirConst in ailang-mir). A non-literal const
    (e.g. a List ctor expression) needs a typed body once the consumer
    walk takes &MTerm; literal consts emit a global and need no body.
  - MirModule gains `ast: Module`, populated by lower_module — forward
    scaffolding the mir.1b codegen consumption reads for module
    structure. Populated here, consumed by the in-tree switch.

Verification: full `cargo test --workspace` green (697 passed, 0 failed)
with the codegen-consumption switch stashed out, including the new pin
crates/ailang-check/tests/lower_to_mir_ty.rs::poly_free_fn_accumulating_into_own_adt_elaborates
(RED before the localize fix with the exact mismatch above, GREEN after)
and the full e2e corpus (the own-ADT-poly demos elaborate clean and run
through the old codegen). This proves the producer fix is
regression-free and the remaining 22 e2e reds in the working tree are
codegen-consumption defects, not producer defects.
2026-05-31 17:41:05 +02:00
Brummel 135f4ceed7 feat(check): mir.1a — typed-MIR types + post-mono lower_to_mir + elaborate_workspace (additive)
First half of spec iteration mir.1 (docs/specs/0060-typed-mir.md,
plan docs/plans/0114-mir.1a-mir-infrastructure.md). Purely additive: a
new leaf crate plus a post-mono lowering walk plus the front-end entry.
Nothing consumes MIR yet — codegen and the CLI are untouched — so the
whole existing suite stays green (102 test-result-ok lines, 0 failed;
the one ignored is the #49 pin, which lifts at mir.4). mir.1b flips
codegen to consume MIR and deletes the synth_with_extras mirror.

What lands:
- `ailang-mir` (new leaf crate, depends only on ailang-core): MTerm /
  MArg / MArm / MLoopBinder / MNewArg / Callee / Mode / StrRep / MirDef
  / MirModule / MirWorkspace, structurally complete over all 17 Term
  variants plus the dedicated Str split (MTerm::Str{lit,rep}). Every
  later-iteration annotation field exists now at a mir.1 default
  (App.callee = Indirect, MArg.mode/consume_count = Owned/1, Str.rep =
  Static, New.elem = None); the struct shape will not change across
  mir.2–mir.5, only the values. MTerm::ty() reads the carried type.
- `ailang-check::lower_to_mir`: the post-mono walk. Carries no second
  type engine — it calls the canonical `synth` per node with fresh
  throwaway inference scaffolding (subst/counter/residuals/…), applies
  the substitution, and threads only the lexical locals/loop_stack,
  maintained by the same push/pop rules synth uses (Let, Loop, Lam,
  LetRec, and Match via synth's own type_check_pattern). This is the
  "one engine, not two" property the milestone buys, on the producer
  side.
- `ailang-check::elaborate_workspace`: the single front-end entry —
  check (diagnostics gate) → desugar+lift → monomorphise → lower_to_mir
  — transcribed from the CLI build path. check_workspace stays for the
  diagnostics-only callers.
- Three ty-fill pins (crates/ailang-check/tests/lower_to_mir_ty.rs)
  load the #51/#53/#49 witnesses as fixtures and elaborate the whole
  workspace, so lower_to_mir is exercised over the full prelude+kernel,
  not just the tiny witness. Two new witness fixtures
  (examples/new_{rawbuf_size_only,counter_user_adt}.ail); #49 reuses the
  existing loop_recur_str_binder_no_leak_pin.ail.

Deviations from the plan, all forced by ground truth and verified
against the live code before commit:
- FnDef.export is Option<String>, not bool — dropped from MirDef (the
  plan's note allowed this fallback). Codegen reads FnDef.export
  directly, unaffected.
- fn_param_types did not exist — lifted the param-type extraction into
  a shared pub(crate) fn and rewired both mono.rs sites
  (collect_mono_targets, collect_rewrite_targets) to it, so the
  param-type source cannot drift between mono and lower_to_mir. The
  helper unwraps a top-level Forall then reads Type::Fn.params —
  identical to the inner_ty extraction it replaces; the early-return
  non-fn guard is preserved at both sites. Behaviour-preserving (whole
  suite green; this is the only edit to existing mono behaviour).
- lower_module mirrors two more mono.rs scaffolding rules the plan
  under-transcribed: skip intrinsic-bodied fns (they are
  signature-only; lowering them would hit synth's Term::Intrinsic
  guard) and seed env.current_module + env.globals + env.imports per
  module so synth's Var lookup resolves post-mono specialisations
  (e.g. compare__Int) in the prelude.
- The #53 pin asserts the lowered (new Counter 42) init carries ty
  Counter, not that it is an MTerm::New: a monomorphic `new` over a
  user ADT is desugared to a dotted call `(app Counter.new 42)` before
  lower_to_mir runs (desugar.rs:1078-1098), so it lowers to MTerm::App.
  MTerm::New survives only for a polymorphic `new` carrying a written
  NewArg::Type (the #51 RawBuf path, covered by the rawbuf pin). The
  pin's intent — ty-fill correctness — is preserved; the structural
  variant is mir.2/mir.5 territory.
- ailang-mir uses workspace-inherited Cargo fields for consistency with
  the existing crates (added it to [workspace.dependencies]).

refs #49
2026-05-31 14:04:03 +02:00