Commit Graph

48 Commits

Author SHA1 Message Date
Brummel 47bec74b26 iter 22b.2.10: fix — positive green-path test, drop dead let _ = ws
Adds the missing positive counterpart to the no-instance test:
`show 42` with `instance Show Int` PRESENT must typecheck green.
This guards against registry-keying or threading bugs that would
otherwise sneak past the negative-only test (an empty registry at
typecheck time, or a key shape mismatch, would silently fire
no-instance even when the instance exists).

Also drops the dead `let _ = ws;` and its stale comment in
`check_in_workspace` — the line above already consumes
`ws.registry`, so the explicit drop is redundant. The remaining
comment is folded into the registry-threading comment so the
"registry is the only thing threaded" rationale is preserved.
2026-05-09 19:13:32 +02:00
Brummel 3600e82ec2 iter 22b.2.10: no-instance per-fn diagnostic 2026-05-09 19:07:46 +02:00
Brummel b741a8ba05 iter 22b.2.9: fix — superclass-walk tests, simplify class_superclasses map shape 2026-05-09 18:59:15 +02:00
Brummel 7cff741632 iter 22b.2.9: missing-constraint per-fn diagnostic 2026-05-09 18:51:39 +02:00
Brummel afa06a3f3d iter 22b.2.8: fix — fold double-match, IndexMap parity, broader contract test 2026-05-09 18:37:49 +02:00
Brummel 17605a3327 iter 22b.2.8: register class methods in module globals 2026-05-09 18:33:01 +02:00
Brummel b636b883a3 iter 22b.2.1: add Constraint struct, Type::Forall.constraints 2026-05-09 17:34:39 +02:00
Brummel eb4db9dafc iter 22b.1.2: workspace registry skeleton + coherence checks
Adds the workspace-global typeclass instance registry per Decision 11
"Resolution and monomorphisation". Built at the end of load_workspace
after the DFS over imports completes; keyed by (class-name, type-hash)
where type-hash uses the new canonical::type_hash (16-hex prefix,
parallel to def_hash and module_hash).

Three coherence checks fire from build_registry, each surfacing as a
distinct WorkspaceLoadError variant:

- OrphanInstance: `instance C T` not in C's or T's defining module.
- DuplicateInstance: two entries share the same (class, type-hash) key.
- MissingMethod: instance omits a required (non-default) method.

The CLI's workspace_error_to_diagnostic is extended with the three new
codes (orphan-instance / duplicate-instance / missing-method).

All existing Workspace { ... } construction sites get the new
`registry` field, defaulting to Registry::default() at synthetic /
test-only paths and threading through ws.registry.clone() at codepath
sites that already hold a real workspace.

Includes hash-stability regression tests (iter22b1_schema_extension_*
and iter22b1_classdef_empty_optionals_hash_stable) and the empty-
registry positive test against examples/sum.ail.json. Test count:
288 → 291 (3 new tests, all pass).
2026-05-09 12:37:00 +02:00
Brummel f25d7b6cd6 iter 22b.1.1: ClassDef/InstanceDef AST + downstream match arms
Adds Def::Class(ClassDef) and Def::Instance(InstanceDef) variants per
Decision 11 §"Form-A schema". All optional fields (superclass, doc,
default body) carry skip_serializing_if so canonical-JSON bytes of
pre-22b fixtures stay bit-identical.

Downstream match-on-Def sites are extended with explicit Class/Instance
arms. Behaviour for 22b.1 is placeholder (skip in typecheck/codegen,
one-line summary in pretty/manifest, placeholder marker in prose/print)
with TODO comments naming the deferred sub-iters (22b.2 typecheck,
22b.3 codegen, 22b.4 prose-projection arms).
2026-05-09 12:31:23 +02:00
Brummel 50b68267fe check: mode-strict-because suppression (iter 19b)
Closes the 19a/19a.1/19b arc. Corpus signal from 19a.1 (5/65
fixtures fire over-strict-mode, all deliberate RC codegen-test
fixtures) justified shipping the suppress mechanism end-to-end.

Schema: Suppress { code, because } on FnDef. Pre-19b hashes
bit-identical via skip_serializing_if. Typechecker drops matching
diagnostics; empty 'because' is Error severity; wrong codes are
silent no-ops (open-set registry).

Form-A: (suppress (code "...") (because "...")) clause, parser
+ printer round-trip clean. Form-B: '// @suppress <code>: <reason>'
above the doc string, lossless contract metadata.

5 RC fixtures migrated (.ail.json + .ailx + .prose.txt). Corpus
signal: 5/65 -> 0/65. Lint still fires on any future fn that's
accidentally over-strict without an authored reason.

Test counts: ailang-check 55->61, ailang-core 26->28, ailang-surface
21->26, ailang-prose 49->52, e2e 70 unchanged.

Known debt: .ailx comment headers lost on regen (ail render's
contract excludes comments); parse_suppress_attr accepts
duplicate code/because attrs without diagnose (bounded by canonical
print order).
2026-05-08 19:36:04 +02:00
Brummel 9f3f10ce6e check: precise sub-binder analysis for over-strict-mode (iter 19a.1)
Corpus-signal upgrade: orchestrator ran 19a's lint across 65
fixtures, zero warnings fired. The conservative match-scrutinee
carve-out filtered every (own T) fixture because every such body
destructures the param via match. Real-corpus signal warranted
the precise variant.

Precise rule: for an Own param with consume_count == 0, walk each
match arm whose scrutinee is the param; if any HEAP-TYPED
pattern-binder has consume_count > 0, stay silent (sub-consume
forces ownership). Otherwise fire.

Heap-type filter is the implementer's design call (not in the
brief): reading a primitive (h: Int) is load-by-value, no RC, no
heap-data move; reading heap-typed t: IntList IS a pointer move
requiring outer-cell ownership. Documented in module-doc.

Corpus signal after upgrade: 5/65 fixtures fire — all RC
codegen-test fixtures with deliberate over-strictness for the
codegen path. Justifies 19b (mode-strict-because suppression).

ailang-check test count: 53 → 55. e2e + everything else green.
Known debt: deeply-nested-match-on-sub-binder (no fixture hits).
2026-05-08 19:19:31 +02:00
Brummel 41804a39fb check: over-strict-mode lint (iter 19a)
When a fn-param is annotated (own T) but the body never consumes
it (consume_count == 0) and never destructures it via match, the
linearity pass now emits a Severity::Warning diagnostic with a
form-A-rendered (borrow T) rewrite as suggested_rewrite. Pure
advisory, Decision 10 unchanged.

First Warning-severity diagnostic the typechecker emits; three
CLI exit paths gated on Error-only.

JOURNAL: design entry + iter 19a shipping entry.
2026-05-08 17:56:58 +02:00
Brummel 6b3ff3bbed tidy: rewrite stale 18b/18c.x doc-headers to match shipped state
First half of the post-18-arc tidy-iter (per the new CLAUDE.md
iter-cycle rule). Architect's drift review flagged module-doc
headers describing 18b's leak-everything snapshot or 18c.x's
"deferred" debt that has since shipped. Doc-only changes; cargo
build clean, cargo test --workspace green at e2e=61, no
behavioural change.

- runtime/rc.c top-of-file header: rewrote from "Iter 18b
  deliberately stops at the layout and the alloc... programs
  leak every allocation" (false post-18c.3) to a stage summary
  spanning 18b–18e. Fixed `--memory=rc` reference (renamed to
  `--alloc=rc` in 18b's CLI work). Updated ailang_rc_inc /
  ailang_rc_dec block comments to point at `drop_<m>_<T>` and
  the worklist as the cascade owners, not at "18c will wire
  this up".

- ailang-check uniqueness.rs module-doc: replaced the "deferred
  to later iters" block (which named 18c.4 + 18d as future
  work, both shipped) with a current "what this pass does NOT
  do" block. Cross-fn reasoning is still genuinely deferred;
  per-type drop fns and recursive cascades are NOT this pass's
  job by design (codegen does them, not the inference).

- ailang-codegen emit_drop_fn_for_type doc + in-body comment:
  rewrote "Iter 18e replaces the recursive call with an
  iterative worklist free" to describe the actual shipped
  behaviour — the 18e (drop-iterative) annotation routes
  annotated types through emit_iterative_drop_fn_for_type;
  unannotated types stay recursive by orchestrator design
  (cheaper IR, no worklist alloc).

Held back for the second half of the tidy-iter (pending the
ailang-bencher determinism result):

- DESIGN.md Decision 10 line 700 says modes are "mandatory"
  but lines 940–952 admit they're opt-in with deferred
  mandatoriness. The bench result either supports tightening
  the mandatoriness claim or backs down to "opt-in with
  performance benefit" — orchestrator-level decision blocked
  on the bench data.
- Dynamic-tag partial-drop debt is captured in JOURNAL but
  should be surfaced in DESIGN as a known precision gap.
2026-05-08 13:34:32 +02:00
Brummel ce6ab8ee44 Iter 18e: (drop-iterative) annotation + worklist allocator
Closes the 18-arc's stack-recursion limit. Recursive drop
cascades from 18c.4 overflow on long ADT chains (Linux's 8 MB
default stack maxes out around 1M cells of List). The new
opt-in (drop-iterative) annotation on a Def::Type switches the
synthesised drop_<m>_<T> body from recursive to iterative-with-
explicit-worklist for that type.

Schema:
- TypeDef.drop_iterative: bool. Default false; serde-skip
  when false so existing fixtures' canonical JSON hashes stay
  stable.
- Form-A: (drop-iterative) clause inside (data T ...).

Worklist runtime (4 new ABI symbols in runtime/rc.c):
- ailang_drop_worklist_new(initial_capacity)
- ailang_drop_worklist_push(wl, ptr)
- ailang_drop_worklist_pop(wl) -> ptr
- ailang_drop_worklist_free(wl)

Heap stretchy buffer, doubling on overflow, null-filtering on
push. Lean 4 / Roc precedent documented in the runtime; the
slot-repurposing strategy was considered and rejected because
not every box has a free pointer-typed slot to thread the
worklist through (Cons head is i64, slot 1 is ptr but it's
the field we're following — no free slot).

Codegen (emit_iterative_drop_fn_for_type): for a
drop_iterative type, drop_<m>_<T>(ptr %p) emits a worklist
loop. Fields of the SAME annotated type push onto the
worklist (mono-typed); fields of DIFFERENT types call their
own drop fn directly (recursive on those, but only if THEY
are themselves recursive — i.e. one level of cascade jump
maximum). Mono-typed-worklist is sound for the deep-self-
recursion case the iter targets (List of List of T just
needs the spine flattened).

Tests:
- examples/rc_drop_iterative_long_list — 1M-cell List of Int
  with (drop-iterative) annotation.
- alloc_rc_drop_iterative_handles_million_cell_list E2E —
  builds + runs under --alloc=rc, asserts clean exit. With
  annotation: exits 0. Without annotation (control): SIGSEGV
  at exit code 139 (verified by hand). Worklist is load-
  bearing.
- iter18e_drop_iterative_emits_worklist_body_no_self_recursion
  IR-shape: worklist body has br to loop_head AND no direct
  recursive call into drop_<m>_<T>.
- iter18e_no_annotation_keeps_recursive_drop_body — control:
  unannotated variant still emits the 18c.4 recursive shape.
- 3 surface parse-tests for the annotation round-trip.

Test deltas: e2e 58 -> 61 (+3), surface 18 -> 21 (+3). All
other buckets unchanged. cargo test --workspace green.

Known debt (deliberate):
- Mono-typed worklist: cross-type drop-iterative fields call
  the other type's drop fn directly. A heterogeneous
  worklist would be more general but adds tag tracking
  complexity for a case (drop-iterative T containing
  drop-iterative T') that's narrower than the deep-self-
  recursion target. Documented in
  emit_iterative_drop_fn_for_type's doc.
- Closure / Type::Var / Type::Forall fields fall back to
  shallow ailang_rc_dec via field_drop_call — same as the
  recursive variant.
- Dynamic-tag partial-drop fallback (head_or_zero epilogue
  shallow dec when moved_slots non-empty) — out of scope per
  brief.
2026-05-08 12:53:09 +02:00
Brummel 73545ab086 Iter 18d.2: codegen reuse-as in-place rewrite under --alloc=rc
Lowers Term::ReuseAs { source, body=Term::Ctor } under
--alloc=rc to a runtime refcount-1 dispatch. At the reuse-as
site:

  %hdr_ptr = getelementptr i8, ptr %src, i64 -8
  %refcnt  = load i64, ptr %hdr_ptr
  %is_one  = icmp eq i64 %refcnt, 1
  br i1 %is_one, label %reuse, label %fresh

The reuse arm overwrites the source's box in place: stores the
new tag at offset 0 and the new field values at offsets 8, 16,
... — no malloc, no outer drop. The fresh arm allocates a brand-
new box via ailang_rc_alloc, stores tag and fields, then shallow-
dec's the source. Both arms phi-join to the same `ptr` result.

Other allocators (gc, bump) keep 18d.1's identity behaviour
unchanged.

Static shape compatibility is enforced by a new pre-codegen
pass crates/ailang-check/src/reuse_shape.rs. It tracks the
path-resolved ctor of every let-bound and pattern-matched
binder, then checks each Term::ReuseAs site against the body's
ctor. Mismatches emit reuse-as-shape-mismatch with stable
ctx.reason sub-codes (field-count-mismatch, field-type-mismatch,
indeterminate-source-ctor, cross-module-body-ctor, ctor-not-in-
module) and a drop-the-wrapper SuggestedRewrite. Build fails on
mismatch — the structured diagnostic tells the author whether
to fix the shapes or remove the hint.

Field-cleanup design — deliberate scope cut:

The reuse arm does NOT dec the old pointer-typed field values
before overwriting them. Doing so on the canonical fixture
`(reuse-as xs (Cons (+h 1) (map_inc t)))` causes use-after-free:
the recursive map_inc(t) returns t's in-place-rewritten box, so
the "new tail" being stored is the same pointer as the "old
tail". A dec-old-then-store-new schedule would dec the box (to
zero, free), then store the freed pointer.

The root cause is upstream: 18c.4 doesn't yet null-out pattern-
moved field slots, so codegen can't statically distinguish
"old field still owned" from "already moved out". The chosen
trade-off: skip the field dec entirely; pattern-wildcarded
fields (rare in shipping fixtures) leak; pattern-moved fields
are the body's responsibility (consistent with the 18c.4 leak
baseline — Own params still leak today). 18d.2 ships zero
regression vs 18c.4, plus the perf win on the alloc + outer
cascade. Closing the leak is the move-aware-pattern story
queued for 18d.3 / 18e.

Tests:
- e2e reuse_as_demo_under_rc_uses_inplace_rewrite — runs
  examples/reuse_as_demo.ail.json under --alloc=rc, asserts
  stdout 9 and locks in the IR shape (icmp eq i64 ..., 1; the
  reuse arm has no @ailang_rc_alloc call).
- workspace reuse_as_shape_mismatch_is_reported_on_cons_to_nil
  — happy negative for the new diagnostic.
- 3 unit tests in reuse_shape::tests covering same-ctor-clean,
  cons-to-nil-reject, and indeterminate-source-ctor-reject.

Test deltas: e2e 56, ailang-check unit 46 -> 49 (+3), workspace
9 -> 10 (+1). cargo test --workspace green. Hand-verified
--alloc=rc binary on reuse_as_demo: stdout 9, exit 0.
2026-05-08 11:21:02 +02:00
Brummel 74379b29e5 Iter 18d.1: Term::ReuseAs schema + linearity check
Schema floor for explicit reuse hints. Adds Term::ReuseAs
{ source: Box<Term>, body: Box<Term> } with serde tag "reuse-as",
form-A (reuse-as <source> <body>). Schema choice (wrapper, not
modifier-on-Ctor) and rationale recorded in DESIGN.md.

Codegen is identity under all --alloc strategies — lower body,
drop source on the floor. Iter 18d.2 will lower this as the
in-place rewrite under --alloc=rc.

User-facing diagnostics:
- typecheck reuse-as-non-allocating-body: body must be a
  Term::Ctor or Term::Lam, the two AST shapes that allocate.
  Other shapes (literal, var, app, ...) emit this with a
  suggested_rewrite that drops the wrapper.
- linearity reuse-as-source-not-bare-var: source must be a
  Term::Var referring to an in-scope binder. Anything else
  (literal, nested expression) is rejected here. Suggested
  rewrite drops the wrapper.
- linearity use-after-consume at a reuse-as site: source must
  not have been consumed earlier in the body. Suggested rewrite
  drops the wrapper.
- Visiting reuse-as marks source consumed for the rest of the
  body, so a subsequent use of the same binder flags
  use-after-consume against it.

Uniqueness inference treats source as Consume — the consume
shows up in the side table for the codegen consumer.

Tests:
- 4 surface parse-tests (round-trip, no-args, one-arg, full
  parse_term/term_to_form_a round-trip).
- 1 typecheck unit test (non-allocating body).
- 2 linearity unit tests (non-var source, after-consume).
- 1 integration test (happy-path map_inc in all-explicit mode
  is linearity-clean).
- 1 E2E test running the canonical map_inc-via-reuse-as fixture
  under --alloc=gc, asserting stdout 9.
- New fixture examples/reuse_as_demo.{ailx,ail.json}.

Test deltas: E2E 55 -> 56, ailang-check unit 43 -> 46,
ailang-check workspace 8 -> 9, surface 14 -> 18. cargo test
--workspace green. No existing fixture's canonical JSON changed.
2026-05-08 10:55:31 +02:00
Brummel 307a3ea848 Iter 18c.3: uniqueness inference + non-recursive RC inc/dec
Ends the leak-everything era under --alloc=rc. Codegen now emits
ailang_rc_inc at every Term::Clone site and ailang_rc_dec at
end-of-scope of trackable RC-allocated let-binders. Default
--alloc=boehm path is byte-identical to before this iter.

Two parts:

(A) New module ailang-check::uniqueness — post-typecheck
    dataflow producing UniquenessTable: BTreeMap<(def, binder),
    UniquenessInfo>. consume_count is max-over-paths: at if/match
    the walker saves state, walks each arm against the snapshot,
    and merges by taking the per-binder max. Term::Clone is a
    Borrow on its inner term — the explicit clone is the user's
    signal that a fresh ref is being produced via inc.

(B) Codegen emission in ailang-codegen. Term::Clone emits inc
    under --alloc=rc, gated on val_ty == "ptr" and
    !val_ssa.starts_with('@') (top-level fn closure-pair globals
    live in the LLVM data segment, not in runtime/rc.c's heap).
    Term::Let emits dec at scope close iff the value is
    rc_alloc'd (Term::Ctor / Term::Lam in escape set under
    --alloc=rc), val_ty == "ptr", consume_count == 0 (no callee
    or outer site already took ownership), body's tail SSA is
    not the binder itself (caller-takes-ownership case), and the
    block isn't already terminated.

Header declares of @ailang_rc_inc / @ailang_rc_dec are gated on
--alloc=rc so Boehm/Bump IR shape is unchanged.

Fixture examples/rc_box_drop.ail.json: single-cell Box(Int) ADT
where shallow free is sufficient (no boxed children). E2E test
alloc_rc_emits_dec_for_unique_let_bound_box runs it under both
gc and rc, asserts byte-identical stdout, clean exit, expected
output (42).

Scope cuts deferred to 18c.4: per-type drop fn / recursive dec
cascades for ADTs with boxed children (List, Tree still leak
their tails). Fn params have no dec emission yet (no static
"caller handed off ownership" signal under Implicit mode);
under explicit (own T) the signal exists but wiring is 18d.

Tests: E2E 52 -> 53, ailang-check unit 38 -> 43 (+5 uniqueness),
all other buckets unchanged. cargo test --workspace green.
2026-05-08 10:25:22 +02:00
Brummel 09fb5bb113 Iter 18c.2: linearity check + suggested_rewrites
Adds a per-fn linearity check that runs on every fn whose
param_modes are all explicit (Borrow or Own, no Implicit), tracks
each binder's consume/borrow state through the AST, and emits
two diagnostics with form-A `suggested_rewrites`:

- `use-after-consume` — a binder is referenced after it has
  already been consumed.
- `consume-while-borrowed` — a binder is consumed while a borrow
  of it is still live (sibling arg slot, or an enclosing-fn
  Borrow param).

Fns with any Implicit param skip the check entirely; that's the
back-compat lane that keeps every existing fixture green. Pure
diagnostic addition: no IR change, no codegen change, no runtime
change.

Each diagnostic carries a non-empty `suggested_rewrites` whose
`replacement` is form-A AILang text (typically `(clone <name>)`).
Adds two new public entrypoints to ailang-surface — `parse_term`
and `term_to_form_a` — so the round-trip
`parse_term(term_to_form_a(t)) ≡ t` is the contract every
emitted replacement must satisfy. Tests assert the contract.

Linearity pass runs only on modules that typechecked clean (any
upstream typecheck error suppresses it for that module — running
on partly-defined IR would produce noise).

Tests: 3 unit tests in `linearity::tests`, 3 integration tests
in `ailang-check/tests/workspace.rs`, 1 serialisation test in
`diagnostic.rs`. `cargo test --workspace` green.
2026-05-08 10:06:14 +02:00
Brummel 7dfc88a4f3 Iter 18c.1: Term::Clone schema (no inc emission yet)
Adds (clone X) as a new Term variant. Form-A:
  (let p (expensive_fn x)
    (do consume_a (clone p))    ; explicit RC inc — needs 18c.3
    (do consume_b p))

Schema floor for the LLM-aware RC design (Decision 10): explicit
clone is the author-visible alternative to implicit sharing. In
18c.1 the variant is purely additive — typechecker treats it as
identity (same type as inner), codegen lowers it to the inner
term's IR with no extra calls. Iter 18c.3 will replace the
codegen identity-arm with a single call:

  Term::Clone { value } =>
      let v = self.lower_term(value, ...)?;
      self.emit("call void @ailang_rc_inc(ptr {v})");
      Ok(v)

Match-arm count: ~10 sites across 6 files, all mechanical
structural recursion through `value`. The codegen `lower_term`
arm carries an explicit comment marking the 18c.3 emission seam.

Hash invariant: `(clone X)` uses a new serde tag "clone" that no
pre-18c.1 fixture contains. Every existing fixture's canonical
JSON is bit-identical (git diff examples/ empty).

New fixture examples/clone_demo.{ailx,ail.json}:
  (let x 42 (do io/print_int (clone x)))
Stdout 42 under both --alloc=gc and --alloc=rc.

Tail-position propagates through clone (verify_tail_positions
treats `(clone tail-call)` as itself a tail call), per the
identity-of-clone semantics in 18c.1.

Verified:
- cargo build --workspace clean
- cargo test --workspace green: 52 e2e (+1), 14 surface parse
  (+2 for clone tests), all other buckets unchanged
- ail render round-trip exact
- clone_demo --alloc=gc → 42; --alloc=rc → 42
2026-05-08 02:26:12 +02:00
Brummel b9ca8894a5 Iter 18a: (borrow T) / (own T) mode annotations on fn signatures
Adds form-A surface (borrow T) / (own T) wrappers in fn-type
params and ret slots. Internally these are not new Type variants
but per-position metadata on Type::Fn:

  Type::Fn { params, param_modes, ret, ret_mode, effects }
  enum ParamMode { Implicit, Own, Borrow }

This keeps Type itself unchanged, so unification, occurs, apply,
and ~190 other Type match-arms in the typechecker need no new
branch. Fields use serde skip-if-default predicates so canonical
JSON hashes for every pre-18a fixture stay bit-identical (sum,
list, hof, closure, list_map, etc.: zero diff under git).

Iter 18a is purely additive: typechecker treats modes as
transparent (mode-compat check deferred to 18c), no codegen
change (--alloc=gc / Boehm path unchanged), no linearity
enforcement. The annotation info flows into the JSON side-table
that 18c will consume.

Equality of mode slices is length-tolerant: a vec![] (the form
written by mechanically-updated construction sites that elide
modes) compares equal to vec![Implicit; n]. This kept the patch
from being a 100-site mechanical migration through the
typechecker. 18c will choose: keep the slack, or normalise to
full-length on construction.

New fixture examples/borrow_own_demo.{ailx,ail.json} exercises
both modes. list_length declares (borrow (con List)); sum_list
declares (own (con List)). Stdout: 3 then 6.

Documentation: DESIGN.md schema-additions block clarified that
modes are Type::Fn metadata (not Type variants); migration plan
flag rename --memory=rc → --alloc=rc to match the existing CLI
flag.

Verification:
- cargo build --workspace green
- cargo test --workspace green (154 tests, +1 vs baseline 153)
- git diff examples/{sum,list,hof,closure,list_map,...}.ail.json: empty
- borrow_own_demo runtime stdout: "3\n6\n"
- canonical JSON contains "param_modes":["borrow"] and ["own"]
2026-05-08 02:07:07 +02:00
Brummel 937782e36d Iter 16e: == polymorphic over Int / Bool / Str / Unit
Lifts the Int-only restriction on `==`. Declared type becomes
forall a. Fn(a, a) -> Bool; codegen monomorphises and dispatches:

  Int  → icmp eq i64
  Bool → icmp eq i1
  Str  → call @strcmp + icmp eq i32 0
  Unit → constant true (operands still emitted for side effects)
  ADT / Fn / other → CodegenError::Internal

This unblocks 16c's build_eq for non-Int lit patterns. == joins
__unreachable__ as the second polymorphic builtin (same Forall
machinery).

- check/builtins.rs: == registered as Forall(a, Fn(a, a) -> Bool).
- codegen: lower_eq dispatch table; @strcmp declared in IR header
  alongside @printf/@GC_malloc/@puts.
- examples/eq_demo.{ailx,ail.json}: covers all four supported
  scalars including a Str-lit-pattern match.
- IR snapshots refreshed: only +declare i32 @strcmp(ptr, ptr) in
  the header; every define body bit-identical.
- e2e + check + codegen tests: 124 → 133 (+9, of which +1 is the
  e2e fixture and the rest exercise the new dispatch / typecheck
  surface).

Other comparison ops (<, <=, >, >=, !=) remain Int-only — out of
scope for this iter.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 23:12:24 +02:00
Brummel af35612c1d Iter 16d: chain-terminator via __unreachable__ builtin
Eliminates the Unit-typed chain default that 16c left in place.
Adds __unreachable__ : forall a. a — codegen lowers to LLVM
unreachable. The 16a/16c chain machinery now uses it as the
deepest fall-through, so exhaustive matches with non-Unit arms
no longer need a (case _ ...) workaround.

- check/builtins.rs: register __unreachable__ as Forall(a, a).
- codegen: Term::Var "__unreachable__" emits LLVM unreachable
  and sets block_terminated; If/Match/fn-body gate downstream
  work on that flag.
- desugar: chain default switched from Lit{Unit} to Var.
- examples/lit_pat: categorize_first's trailing _ arm removed.
  Hash changes from c4faec3abc2ed388 to 644de0c0ec15fc17.
- examples/unreachable_demo: positive fixture using safe_div
  with __unreachable__ in the impossible branch.
- e2e + desugar tests: 122 → 124 (+2).

Path-a from 16b.2 planning: real primitive over a desugar-time
exhaustiveness pre-check (which would need cross-module type
registry access from desugar).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 23:00:23 +02:00
Brummel e5f9828a04 Iter 16b.7: nested LetRec mutual capture (params, not name)
Inner LetRec capturing outer LetRec's params now lifts cleanly via
the existing post-order traversal — outer's params are KnownType
in inner's outer-scope, so 16b.2's fast-path handles them. Inner
LetRec capturing outer's NAME remains rejected (closure-of-self
in body, deferred separately).

Plus hardening: lift.rs's deferred path tracks the outer LetRec
name in a parallel `enclosing_letrec_names` set so the symmetric
inner-captures-outer-name rejection fires there too — without it
a silent lift produced a runtime arity mismatch.

- examples/nested_let_rec.{ailx,ail.json}: outer counts down via
  inner that captures the outer's threshold param.
- desugar.rs: clarified panic message for outer-name capture.
- lift.rs: enclosing_letrec_names tracking.
- e2e + desugar tests: 120 → 122 (+2).

End-of-16b series: feature-complete except for closure-of-self
in body and closure-with-polymorphism, both queued separately.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 22:48:14 +02:00
Brummel 76d61aeced Iter 16b.6: LetRec inside polymorphic enclosing fn
Lifts the monomorphic-only restriction. Lifted top-level fn now
becomes Forall(α..., Fn(t..., T...) -> tr) when the enclosing fn
is polymorphic; capture types may mention outer type vars and
the existing mono pipeline (Iter 12b/14a) specializes them
correctly at call sites.

- desugar.rs / lift.rs: scope-building unified — Forall fn-params
  are now KnownType, not LetBound. Lift wraps augmented_ty in
  Forall mirroring the enclosing fn.
- Name-as-value-in-in-term in a polymorphic enclosing fn is
  rejected (eta-Lam wrap from 16b.5 has no Forall). Queued
  separately as closure-conversion-with-polymorphism.
- examples/poly_rec_capture.{ailx,ail.json}: apply_n_times :
  Forall(a). drives at Int and Bool to exercise two mono
  instantiations.
- e2e + check + desugar tests: 116 → 120 (+4).

Codegen pipeline untouched — apply_subst_to_type substitutes
through Fn.params uniformly (original params + appended captures).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 22:39:28 +02:00
Brummel ca507c9f52 Iter 16b.5: LetRec name as value (in_term only) via eta-Lam wrapper
Drops the direct-call-only restriction on the LetRec name when it
appears in `in_term`. No new ABI: the lift wraps the in-term in
`(let f (lam P (app f$lr_N P CAPTURES)) in_term')` so codegen's
existing Iter-8b closure-pair machinery handles it. Body-position
name-as-value still rejected (deferred — eta-of-self is harder).

- desugar.rs / lift.rs: split find_non_callee_use into body
  (panic) and in_term (wrap).
- examples/local_rec_as_value.{ailx,ail.json}: no-capture path
  (factorial passed to apply5 → 120).
- examples/local_rec_as_value_capture.{ailx,ail.json}: capture
  path; lifted fn has captures, eta-Lam picks them up via 8b.
- e2e + desugar tests: 113 → 116 (+3).

Codegen Lam machinery handled the wrapped form on the first try.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 22:27:21 +02:00
Brummel c0668178bb Iter 16b.4: LetRec captures of match-arm pattern bindings
Flips the desugar's MatchArm-capture rejection from panic to defer.
The 16b.3 lift_letrecs pass already handled match-arm bindings via
type_check_pattern_for_lift (Pattern::Var, Pattern::Ctor with sub-
patterns, ctor-field substitution against scrutinee args), so this
iter is a single-line classification change in desugar plus the
fixture and tests that exercise it.

- desugar.rs: MatchArm classification now defers (same arm as
  LetBound); EnclosingLetRec panic remains for 16b.7.
- examples/local_rec_match_capture.{ailx,ail.json}: enclosing fn
  pattern-matches on Pair<Int,Int>, inner LetRec captures both
  match-arm bindings simultaneously. Lifts to
  loop$lr_0(i: Int, threshold: Int, n: Int) -> Int.
- e2e + check + desugar tests: 110 → 113 (+3).

First fixture lifting more than one capture; subst_call_with_extras
already handled it generically.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 22:16:12 +02:00
Brummel ca30606aec Iter 16b.3: post-typecheck lift for LetRec with Let-bound captures
Adds path-2 from the 16b.2 planning entry. Desugar now defers
LetRecs whose captures include Term::Let-bound names; a new
ailang-check::lift_letrecs pass runs after typecheck and uses the
elaborated env to resolve capture types. ailang-check learns a real
Term::LetRec typing rule in synth and verify_tail_positions.

- desugar: Term::LetRec arm gains a defer-arm; helpers promoted to
  pub for reuse by the lift pass; find_non_callee_use moved before
  classification.
- ailang-check::synth/verify_tail_positions: real LetRec rules
  (effect-subset, locals install, recursive name in body+in_term).
- ailang-check::lift.rs (new, 720 LOC): post-typecheck lift with
  post-order traversal, env-walk for capture-type resolution,
  fast-path skip when no LetRec is present.
- ail::main.rs: build path now does load → check → desugar →
  lift_letrecs → codegen.
- examples/local_rec_let_capture.{ailx,ail.json}: new fixture
  capturing a let-bound `threshold` in a recursive helper.
- e2e + check unit tests: 106 → 110 (+4).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 22:07:05 +02:00
Brummel 8860600e37 Iter 16b.1 — local recursive let (no-capture)
Add `(let-rec NAME (params ...) (type ...) (body ...) (in ...))`
as a form-A surface and a `Term::LetRec` AST variant. The 16a
desugar pass lifts each LetRec whose body has no captures from
the enclosing scope to a synthetic top-level fn `<hint>$lr_N`
and substitutes the original name; typecheck and codegen never
see LetRec. Capture detection panics at desugar time, queued
for 16b.2.

Tests: 95 → 99 (+1 e2e local_rec_factorial_demo, +2 desugar
unit, +1 parse unit). The new fixture `examples/local_rec_demo`
runs `fact` at n=1, 3, 5 → prints 1, 6, 120.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 20:33:48 +02:00
Brummel 0e90709a94 Iter 16a: nested constructor patterns via AST desugaring
Lifts the gate that rejected `(pat-ctor Cons a (pat-ctor Cons b _))`.
Approach: a pure AST → AST pass `ailang_core::desugar::desugar_module`
that flattens nested-Ctor sub-patterns into chains of single-level
matches with let-bound fresh vars and duplicate fall-through. Both
ailang-check and ailang-codegen call the pass at pipeline entry.
Hash-relevant canonical bytes are untouched: the pass runs after
load_module, in memory only. `check`'s returned CheckedModule.symbols
still carries hashes of the original defs so `ail diff` / `ail manifest`
see on-disk identities.

Lit sub-patterns inside a Ctor still rejected — that's the narrower
scope of `nested-ctor-pattern-not-allowed` post-16a; the variant doc
reflects the new meaning.

Fresh-name safety: `$` is a valid ident character in form (A), so
the Desugarer pre-walks every Term::Var / Pattern::Var name into a
BTreeSet and bumps its counter past any user-spelled `$mp_N`.

Already-flat matches go through `is_flat()` and emit identical AST
shapes; every existing fixture produces the same output as before.

New: examples/nested_pat.{ailx,ail.json} prints 30 from
first_two_sum on [10, 20, 30]. e2e test
`nested_ctor_pattern_first_two_sum` guards the path.

Tests: 92/92 (e2e 32→33, ailang-core unit 10→12).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 19:10:01 +02:00
Brummel 92f4b4f8c7 Iter 15b: std_list ships, three more compiler gaps closed
Second stdlib module. Tester wrote std_list.ailx (10 combinators,
164 LOC) and a consumer demo. std_list typechecked standalone;
demo did not, surfacing three compiler bugs:

1. Check-side: Iter 14h's qualify_local_types was applied to
   Term::Var cross-module lookup but not to ctor-field types in
   Term::Ctor synth or Pattern::Ctor resolution. First recursive
   cross-module ADT (List has Cons a (List a) — recursive Con
   self-ref) triggers the bug. std_maybe slipped through because
   Maybe's ctors have no recursive Con field.
2. Codegen-side: same gap mirrored across 4 sites in codegen
   (Term::Ctor synth, lower_ctor, lower_match) plus a tweak to
   unify_for_subst (recurse on re-bind instead of strict equality
   so sibling-derived List<Int> accepts nullary-ctor's List<$u>
   wildcard).
3. Const codegen: emit_const rejected non-literal const bodies.
   The demo's xs : List<Int> = Cons 1 (...) requires it. Fix:
   per-module const table, Term::Var resolution loads literal
   consts from global, inlines non-literal bodies. Bare and
   qualified refs both supported.

All three fixes carry an "Iter 15b" code comment at their site.
~349/25 LOC across ailang-check, ailang-codegen, e2e.rs.

Tests 85 -> 87. New e2e std_list_demo asserts 11-line stdout:
length 5, is_empty false/true, head via from_maybe, tail length,
append length, reverse head, map double head, filter is_even
length, fold_left sum, fold_right sum. New ailang-check unit
test cross_module_recursive_adt_term_and_pat_ctor covers both
the original bug and the symmetric pat-ctor latent twin.

Hash invariance: all pre-15b fixtures + std_maybe defs
bit-identical. 14a / 14e / 14h regressions all green.

Cumulative state: 2 stdlib modules (std_maybe, std_list), 14
combinators, cross-module recursive ADT working end-to-end.
Three compiler bugs surfaced + fixed in dogfood since 14a (each
dogfood iter has surfaced ≥1).

Authoring observation: form (A) at 10 combinators is fine; main
friction is paren-counting in nested seq chains, not the form
itself. n-ary seq would help but is sugar.

Plan 15c: 1000-element list stress test for fold_left (tail-call-
marked) vs fold_right (constructor-blocked).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 18:34:49 +02:00
Brummel 12e9a9c0cc Iter 14h: cross-module parameterised-ADT import (15a unblocked)
The 15a tester surfaced a real compiler limitation: cross-module
type and ctor references were not implemented. Iter 5b only
carried fns + consts via module_globals; types/ctors stayed
module-local with an explicit DESIGN comment. This iter completes
the cross-module mechanism using the Iter-5b convention:
qualified-only access via module.Name.

Implementation:
- ailang-check: Env.module_types populated by build_module_types.
  Qualified resolution in Type::Con, Term::Ctor, with cross-module
  fallback for pat-ctor (local wins, multi-import collision -> new
  ambiguous-ctor diagnostic). Four new unit tests.
- ailang-codegen: workspace-level module_ctor_index replaces
  per-Emitter table. lookup_ctor_by_type / lookup_ctor_in_pattern
  thread qualified type names through box-tag and field-type
  resolution.
- examples/std_maybe_demo.{ailx,ail.json}: type-name slots now
  qualified (std_maybe.Maybe).
- New e2e test cross_module_maybe_demo asserts the demo prints
  ["7","99","true","true","42"].

Net diff ~550 LOC. Tests 80 -> 85. All Iter 14a regressions
(parameterised_box_round_trip, parameterised_maybe_match,
list_map_poly_inc_then_prints, polymorphic_id_at_int_and_bool)
verified green — the 14h derive_substitution change (default
unpinned forall vars to Unit for monomorphiser) sits on a
different layer than 14a's $u-wildcard fix and they coexist.

Hash invariance: all five std_maybe def hashes unchanged. All
80-test-suite fixtures retain bit-identical hashes — cross-module
support is purely additive at the language level.

Process note: the std_maybe.ailx file landed in the 14g commit
via a sloppy git-add-A; should have spotted it before staging.
Not a correctness issue but a hygiene one.

Implementer flagged Unit-default monomorphisation as wasteful-
but-correct; rethink if stdlib grows toward overload-resolution-
style cases needing distinct unconstrained instantiations.

std_maybe stdlib effectively ships: module + four combinators +
e2e-tested consumer demo. Plan 15b: std_list importing std_maybe,
exercising Maybe-returning head/tail and tail-call-marked
fold_left.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 18:08:56 +02:00
Brummel 41d406bcbb Iter 14g: Term::If restored (revert of 14d)
Reconsidered 14d's removal of Term::If. The decision was wrong.
"No redundancies" requires judgment; reducibility (if -> match)
is not redundancy in the strong sense. Term::If is a primitive
control-flow shape; bool branching is the second most common
shape after sequencing, and removing it cost 3x tokens on every
branch site (`(if c a b)` 4 tokens vs the match-on-Bool form
12 tokens).

Meta-pattern fixed: I had been treating user observations as
directives. User said "if is a subset of match"; I jumped to
remove it citing CLAUDE.md, with no independent conviction.
The leak appeared in 14f's JOURNAL prose ("three lines for what
if used to do in one"), which read as regret. Two feedback
memories saved (memory/feedback_user_suggestions_not_directives,
memory/feedback_no_nostalgia_for_removed_features) to head this
off.

Implementation: mechanical reverse-application of 14d's diff at
every site (AST, check including the 14e tail-position arm,
codegen 4 sites, surface parser/printer, pretty, CLI walker,
e2e test mutation). Removed lower_bool_match helper — it existed
only because 14d's migration shape needed codegen for non-ptr
match scrutinees; with Term::If back, match-on-Bool returns to
its pre-14d unsupported state. Three fixtures (sum, sort, max3)
restored to pre-14d shape. gc_stress (added in 14f) also
migrated back to (if ...) since it was authored under the wrong
constraint.

14e (musttail) and 14f (GC_malloc) verified intact in IR.

Hashes restored to pre-14d values:
- sum.sum: db33f57cb329935e
- sort.insert: 697fcb9f30f8633a
- max3.max: 65c45d6a45dd0a72
- max3.max3: 624b14429bf302f5

All other defs across all 18 fixtures keep their post-14f
hashes. Tests 80/80 green; cargo doc 0 warnings. LOC delta
+265/-295 net -30.

DESIGN.md Decision 7 preserved with a "Status: REVERTED" header
for audit trail. Form-(A) `if-term` production restored.

Plan: back to 15a (std_maybe stdlib module).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 17:45:33 +02:00
Brummel d64031c234 Iter 14e: explicit, verified tail calls
Decision 8 ships. Term::App and Term::Do gain tail: bool with
serde-default false and skip-when-false serialisation. New
typecheck pass verify_tail_positions enforces tail-position rules
(Scheme-style propagation through match arms, seq.rhs, let body,
lam body). Codegen emits musttail call for marked App calls.

Hash invariance verified: only the two migrated print_list defs
(list_map_poly.print_list, sort.print_list) changed hashes; all
other defs across all 18 fixtures kept bit-identical hashes —
confirms the skip-when-false serialisation rule works.

Tests 76 -> 79: tail_call_in_non_tail_position_is_rejected,
tail_call_in_tail_position_is_accepted, plus an IR-grep e2e test
asserting that print_list's recursive call site emits musttail
in the lowered IR. Existing 25 e2e tests unchanged in behaviour
(map -> [2,3,4], sort -> sorted list).

IR evidence at the recursive site:
  %v7 = musttail call i8 @ail_list_map_poly_print_list(ptr %v6)
  ret i8 %v7

Two deviations called out in the implementer report and JOURNAL:
1. tail-do uses tail call, not musttail. Cross-type return
   (runtime helpers return i32, AILang Unit is i8) would have
   LLVM reject musttail. Path is implemented but not exercised
   by any current fixture; proper fix is runtime-helper signature
   change, punted.
2. block_terminated flag in codegen so tail-call emit
   (musttail call + ret) doesn't get a duplicate trailing ret
   from surrounding code (match-arm phi, fn-body, lambda thunk).
   Internal plumbing; required for IR well-formedness.

Form (A) productions now at ~30, exactly the constraint-1
budget. Future surface additions need to retire something or
explicit-budget-rebalance in DESIGN.md.

GC notes from implementer survey land in JOURNAL:
- Allocations cluster in lower_ctor; every term-ctor does
  malloc(8+8n).
- Tail recursion does not reduce alloc pressure, only stack.
  For map-style ctor-blocked recursions, allocation IS the
  bottleneck.
- Per-fn arena is sound only when fn return type contains no
  boxed ADT. Most current fixtures violate this.

Plan 14f: Boehm conservative GC (GC_malloc, -lgc) as a first
cut. Single-iter integration, no AST/schema change. Stress
test: build a 100k Cons list, observe RSS doesn't blow up.

After 14f the language is feature-complete enough for stdlib
work (15a).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 17:16:28 +02:00
Brummel 8d97a924de Iter 14d: remove Term::If as a redundancy
Term::If was semantically a subset of Term::Match on Bool. Per
CLAUDE.md the language must contain no redundancies; two AST nodes
for the same operation produces an authoring decision with no
semantic content and a duplicate codegen path. Removed.

Migration shape (applied to sum, sort, max3 fixtures):
  (if c a b) -> (match c (case (lit-bool true) a) (case _ b))

No schema version bump (per user direction): no third-party consumes
ailang/v0, so version ceremony is pure overhead. Edited AST and
fixtures in place; pinned hashes in hash.rs updated.

Implementer deviation, called out and justified: a tightly-scoped
lower_bool_match helper (~95 LOC) was needed in codegen because
the existing match path rejects i1 scrutinees and Pattern::Lit.
Helper accepts only the canonical two-arm migration shape, errors
on anything else, emits the same br/phi IR Term::If used to. No
generalisation of the ADT-match codegen.

Diff: 13 files, +286/-221 (net +65 LOC). AST got smaller
(one variant gone), form-(A) got smaller (one production gone),
typecheck got smaller (one branch gone). Codegen got slightly
larger by the bool-match helper.

Hash deltas: sum.sum, sort.insert, max3.max, max3.max3 changed.
All other defs (e.g. sum.main, sort.IntList, sort.sort,
sort.print_list, max3.main) kept bit-identical hashes — confirms
canonical-JSON byte format intact.

Verification: 76/76 tests green; sum->55, max3->17, sort->[1,1,2,
3,3,4,5,5,5,6,9] (identical to pre-migration). cargo doc 0 warnings.

Tail-call survey by implementer (informs 14e): print_list
recursions are already in tail position (rhs of seq inside match
arm); map/sort/insert recursions are NOT (constructor-blocked
inside Cons applications). 14e annotation will benefit terminal
recursions; ctor-blocked ones need accumulator-form rewrites in
source, not a compiler-side transform.

Decision 7 added to DESIGN.md. JOURNAL entry has the language-
completion sequence (14d done, 14e tail-calls, 14f GC, 15a stdlib).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 16:56:02 +02:00
Brummel d8727d5bdb Iter 13e: rustdoc polish for ailang-check
Second docwriter mission. Pure rustdoc additions (no API or
behaviour change) across the typechecker crate:

- builtins.rs: module root expanded; EffectOpSig (struct + 3
  fields) and install() got /// strings.
- diagnostic.rs: Severity (+ both variants), Diagnostic (+
  severity/code/message fields) and the error/with_def/with_ctx
  helpers got /// strings; super:: link rewritten to crate::.
- lib.rs: CheckError + every variant, to_diagnostic, CheckedModule
  (+ symbols), check, Env (+ globals/effect_ops/types/
  module_globals/current_module), CtorRef (+ type_name) got ///
  strings; crate-root prose upgraded with intra-doc link to
  check_module.

Verification: cargo doc --no-deps zero warnings; cargo build
--workspace green; cargo test --workspace 64/64 + 3 ignored
doctests green. Diff is 188 LOC, all in /// or //! lines (verified
by filtering).

Findings (not fixed; orchestrator-deferred):
- Env is pub but only privately constructable.
- CheckError::CtorArity and ::ArityMismatch share the public
  diagnostic code "arity-mismatch" by design.
- Diagnostic / Severity reachable via two paths because the
  diagnostic module is pub.

JOURNAL.md updated with the Iter 13e entry. 13f (ailang-codegen
+ ail) and 14a (List a rewrite) remain queued.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 15:13:03 +02:00
Brummel c90926dbba Iter 13d: rustdoc polish for ailang-core + new docwriter agent
Adds ailang-docwriter to /agents/ — a recurring role for keeping
crate-, module-, and pub-item-level rustdoc accurate. First mission:
ailang-core. Crate root, every module root, every pub item documented;
intra-doc links throughout; Iter-13a additions (TypeDef.vars, Type::Con.args)
get an explicit backwards-compat note. Two stale broken-link warnings in
ailang-check fixed in passing. cargo doc --no-deps now warning-free across
the workspace; promoted to verification invariant 6 in DESIGN.md.
2026-05-07 15:02:35 +02:00
Brummel 078262271a Iter 13a: parameterised ADT schema + checker
Adds type parameters to ADTs. `TypeDef` gets a `vars: Vec<String>` and
`Type::Con` gets an `args: Vec<Type>`, both `skip_serializing_if =
"Vec::is_empty"` so canonical-JSON hashes of every pre-13a definition
stay bit-identical (regression test in `hash::tests`).

Checker:
- `check_type_def` installs `td.vars` as rigid vars while validating
  ctor field types — `Cons(a, List a)` now resolves both occurrences
  of `a` and the recursive `List a` use.
- `check_type_well_formed` accepts `Type::Con { name, args }` only
  when the type is in scope and `args.len()` matches its declared
  arity; primitives stay zero-arg.
- `Term::Ctor` synth instantiates `td.vars` with fresh metavars, so
  `MkBox(42)` synthesises to `Box<$m0>` and unifies field types
  through the surrounding context.
- `type_check_pattern` substitutes the scrutinee's concrete type-args
  through ctor field types, so a `MkBox(x)` arm against a `Box<Int>`
  scrutinee binds `x : Int`.
- `check_fn` validates declared param/return types via
  `check_type_well_formed` so arity mismatches on parameterised
  ADTs surface before the body is checked.

`unify`, `occurs`, `Subst::apply`, `substitute_rigids`, and codegen's
`unify_for_subst` / `apply_subst_to_type` recurse into `args`.

Pretty-print:
- `type_to_string` renders `Box<Int>` for parameterised cons.
- `def_block`/`manifest` carry the `[a b ...]` vars list.

Three new check unit tests cover ctor instantiation at a concrete
arg, the polymorphic-`unbox` round trip at two distinct
instantiations, and arity mismatch on `Box<Int, Bool>`. All 62 tests
green; clippy clean (two pre-existing warnings untouched). Hashes
db33f57cb329935e (sum) and b082192bd0c99202 (IntList) verified
unchanged.

Codegen still synthesises `Type::Con` with `args: vec![]` from
`Term::Ctor` — full ADT monomorphisation lands in 13b.
2026-05-07 14:25:58 +02:00
Brummel 1c8c1a0441 Iter 12a: typechecker polymorphism via Forall instantiation
Polymorphism is now opt-in via Type::Forall at top-level def types.
Implementation is the textbook ML rule: peel the Forall when checking
the def body, instantiate fresh metavars at every use site, unify.

Mechanics:
- New Subst struct + unify(): standard occurs-check unification, with
  effects compared as a set.
- Metavars encoded inside the existing Type::Var as Type::Var{name:
  "$m<id>"}. The "$" prefix can't collide with source-level identifiers,
  so the AST schema stays untouched and existing module hashes don't
  shift (verified: sum.ail.json keeps db33f57cb329935e / d9a916a0ed10a3d3).
- check_fn peels an outer Forall and installs the rigid vars in
  Env.rigid_vars, where check_type_well_formed accepts them. Inner
  forall vars unify only with themselves.
- Term::Var lookup runs maybe_instantiate on the resolved type, so
  polymorphic globals get fresh metavars at each occurrence. Two
  use sites of the same `id` get independent ($m0)→$m0 and ($m1)→$m1
  shapes — no bleed.
- All expect_eq calls inside synth replaced with unify; expect_eq is
  still used for the App-arity / etc. structural checks where no
  metavars can appear.

Constraints kept tight on purpose:
- Const types may not be Forall (rejected outright).
- Forall in ADT field positions still rejected.
- No higher-rank polymorphism: App's callee can be Forall (defensive
  instantiate) but the body doesn't introduce new quantifiers.
- No let-generalisation of lambdas — all polymorphism is at top-level
  defs only.

Codegen still rejects Forall types, so polymorphic programs typecheck
but don't yet compile. Iter 12b adds monomorphisation.

Tests: 14/14 (was 10/10) — added polymorphic_id_def_typechecks,
polymorphic_id_can_be_used_at_int_and_bool,
polymorphic_id_consistency_is_enforced, polymorphic_apply_with_two_vars.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 13:32:03 +02:00
Brummel b357a1dc4a chore: clear remaining clippy warnings
Four small cleanups, no semantic change. Workspace is now clippy-
clean (default lints):

- ailang-check: collapse `if-same-then-else` for primitive vs ADT
  type lookup into one branch via a local boolean.
- ailang-codegen: iterate `all_strings.values()` directly instead of
  `for (_mname, entries) in &all_strings`.
- ailang-codegen: drop `import_map` parameter from `collect_captures`
  — was threaded speculatively through every recursive call but
  never read.
- ailang-codegen: `s.len()` instead of `s.as_bytes().len()` in
  c_byte_len (the warning predates Iter 6).

Tests: 52 still green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 13:19:16 +02:00
Brummel c75517ac79 Iter 10: Term::Seq sequencing operator
Adds `Term::Seq { lhs, rhs }` (serde tag "seq") as a first-class
AST node for sequencing effectful expressions. Equivalent in
behaviour to `let _ = lhs in rhs`, but the dedicated node gives the
pretty-printer and diagnostics a cleaner shape and surfaces the
intent ("run for effect, then yield rhs") to future tooling.

Typecheck: lhs must be Unit; rhs's type is the result; effects
accumulate.
Codegen: lower lhs (drop SSA), lower rhs (return).
Capture / deps walkers: recurse into both sides.

Refactored examples/list_map.ail.json's print_list to use seq
instead of `let _ = ...`. Output unchanged (2/4/6).

Hash stability: existing examples without Term::Seq serialise
bit-identical; only list_map.ail.json's hashes changed (deliberate
refactor).

Tests: 51 green (was 50). New unit test
`ailang_check::tests::seq_lhs_must_be_unit` covers the type-error
path; existing list_map e2e covers the happy path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 13:14:28 +02:00
Brummel ecde8fa7af Iter 8b: lambdas with capture (Term::Lam + closure conversion)
Adds anonymous functions to AILang. A lambda value is constructed by
malloc'ing an env struct that holds its captured locals, plus a
closure pair `{ thunk_ptr, env_ptr }` (Iter 8a's ABI). The lambda's
body lifts to a top-level thunk `@ail_<m>_<def>_lam<id>(ptr %env,
params...)` that unpacks captures back into named locals before
running.

AST: new Term::Lam { params, paramTypes, retType, effects, body }.
Serde tag is "lam"; existing modules (no Lam) serialize identically,
so all current hashes stay stable.

Pretty-printer: renders `(\\ (x: T ...) -> R . body)`.

Typecheck (ailang-check): a lambda's type is the declared Type::Fn.
Body's effect set must be a subset of declared effects (no row
polymorphism). Constructing a lambda is pure — only calling it picks
up the declared effects, via the existing App branch.

Codegen (ailang-codegen):
- collect_captures: free-var walk; excludes builtins, current-module
  top-level fns, and qualified names.
- lower_lambda: per-fn lam counter, save/restore emitter state, emit
  thunk into a deferred queue (flushed after the parent fn), pack env
  + closure pair on heap, register the resulting closure-pair SSA in
  the sidetable so subsequent indirect calls find it.
- Capture sigs propagate: a fn-typed capture keeps its FnSig in the
  thunk's sidetable so `f(args)` inside the body still indirect-calls.
- Env layout: 8 bytes per capture (typed load/store reads only the
  needed bytes; padding wasted but uniform).

Tests: 49 green (was 48). New examples/closure.ail.json + e2e
`closure_captures_let_n` exercises `let n = 3 in apply(\\x. x + n, 39)`
end-to-end and asserts the binary prints 42.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 13:03:20 +02:00
Brummel 1a448309fa Iter 6: deps hardening, multi-diagnose, DESIGN audit
- ail deps now filters builtins, fn params, and let/match-pattern
  bindings. New value_names() in ailang-check::builtins is the single
  source of truth shared with the typechecker install path. walk_term
  threads a scope set; qualified `prefix.def` refs pass through.
- check_in_workspace returns Vec<CheckError>; check_workspace
  accumulates body diagnostics across defs and modules. Pass-1
  (top-level symbol table) and per-module type-def setup stay
  fail-fast — corrupt env would taint later diagnostics.
- DESIGN.md "What the MVP is NOT" was lying (ADTs, strings landed
  in Iter 2/3). Renamed to "What is not (yet) supported" and split
  into "not yet" + supported/smoke-tested. JOURNAL Iter 6 entry
  records the architecture self-check.

Tests: 47 green (was 44). +2 deps filter tests in e2e,
+1 multi-diagnose test in ailang-check workspace integration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 12:31:20 +02:00
Brummel 7577ab8a90 Translate project content to English
Make English the project-wide language: all comments, string literals,
CLI help text, design docs, journal, agent prompts, and README. Only
CLAUDE.md (the user's own instruction file) stays German, and the live
conversation between user and Claude continues in German.

Adds a new "Project language: English" section to docs/DESIGN.md as
the durable convention. No logic changes — translation only. Four
internal error strings in the typechecker were retranslated; no
test asserts on their wording.

Verified: cargo test --workspace passes (44/44).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 12:17:48 +02:00
Brummel b2878fe655 Iter 5b: Cross-Module-Typcheck mit qualifizierten Verweisen
Neue API check_workspace(&Workspace) -> Vec<Diagnostic>; check_module
hebt das Modul intern in einen Trivial-Workspace. Term::Var mit genau
einem Punkt im Namen ist ein qualifizierter Verweis <prefix>.<def>,
aufgelöst über Import-Map (alias-oder-modulname → echter Modulname).
Drei neue Diagnostic-Codes: unknown-module, unknown-import,
invalid-def-name. ail check lädt jetzt immer via load_workspace;
Loader-Fehler werden im JSON-Modus zu strukturierten Diagnostics
(module-not-found, module-cycle, …). DESIGN.md und JOURNAL.md
dokumentieren die Konvention. Hash-Stabilität: alle ir_snapshot_*-
Tests bitidentisch grün, kein neuer AST-Knoten.
2026-05-07 11:31:57 +02:00
Brummel 93fe7237e3 Iter 4a: ail check --json mit strukturierten Diagnostics
Neue Top-Level-API check_module(&Module) -> Vec<Diagnostic> in
ailang-check, plus stabile Codes (unbound-var, type-mismatch,
arity-mismatch, non-exhaustive-match, unknown-ctor-in-pattern,
duplicate-def, …). CLI bekommt --json-Flag für maschinenlesbares
Output, Exit 1 bei Errors. Text-Modus unverändert. E2E-Test
check_json_unbound_var sichert das Format ab.
2026-05-07 11:07:36 +02:00
Brummel 21606c9340 Iter 3: ADTs + Pattern Matching
- AST: Def::Type mit Ctors; Term::Ctor (Konstruktion) und Term::Match
  mit Arm/Pattern. Patterns: Wild, Var, Lit, Ctor { ctor, fields } —
  Sub-Patterns im MVP auf Var/Wild beschränkt.
- Typchecker: Type-Registry, ctor_index für O(1)-Resolution, Pattern-
  Bindings, Exhaustiveness-Check gegen volle Konstruktormenge plus
  Negativ-Tests.
- Codegen: Boxed-Heap-Layout via malloc; Tag in Offset 0, Felder ab
  Offset 8 in 8-Byte-Slots. Match lowert zu load tag + switch + Phi
  am Join. Default-Block ist unreachable, wenn vom Typchecker geprüft.
- examples/list.ail.json: rekursive Int-Liste mit sum_list via match.
  E2E-Test + Exhaustiveness-Tests. 19/19 Tests grün.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 10:38:07 +02:00
Brummel 6e6b6a14fb Iter 2: verschachteltes if, Strings, JSON-Output, deps
- Codegen: current_block-Tracking ersetzt die Heuristik im phi-Lowering;
  verschachtelte if-Ausdrücke produzieren jetzt korrekte LLVM IR.
  examples/max3.ail.json + Test schützt gegen Regression.
- Strings: Lit::Str / Type Str / io/print_str Effekt-Op; Strings sind im
  MVP immutable Konstanten. examples/hello.ail.json als zweiter E2E-Test.
- CLI: --json für manifest und builtins; neuer deps-Subcommand listet
  statische Symbol-Referenzen pro Definition. Effekt-Ops mit Prefix
  effect: markiert.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 10:28:16 +02:00
Brummel 2fbcdba0b1 MVP: AILang-Sprache mit JSON-AST, Typchecker, LLVM-IR-Backend
Erste lauffähige Iteration. examples/sum.ail.json wird zu nativem Binary
kompiliert und druckt 55 (Summe 1..10) als End-to-End-Test.

Architektur:
- ailang-core: hashbares JSON-AST + canonical-form + pretty-printer
- ailang-check: monomorpher HM-Subset + Effekt-Set-Tracking
- ailang-codegen: LLVM-IR-Text-Emitter (kein libllvm-link)
- ail: CLI mit check/manifest/render/describe/emit-ir/build/builtins

Designentscheidungen sind in docs/DESIGN.md dokumentiert; der Verlauf
in docs/JOURNAL.md.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-07 10:18:32 +02:00