Five polymorphic prelude free fns (ne/lt/le/gt/ge) plus three E2E
fixtures: positive composition over Int/Bool/Str, user-ADT with
user-written Eq/Ord on IntBox, and Float-NoInstance with a
Float-aware diagnostic addendum cross-referencing DESIGN.md §"Float
semantics".
Two checker-side fixes were needed alongside the prelude additions,
both symmetric to the iter 23.4-prep visibility fix:
- linearity::check_module_with_visible — workspace-aware callee-mode
resolution so a Borrow-mode user fn forwarding into a prelude poly
fn (e.g. `at_most x y = not (gt x y)`) doesn't false-fire
consume-while-borrowed.
- mono::collect_mono_targets — distinguish rigid forall vars from
unbound metavars; rigid-bearing free-fn targets skip (they get
re-collected with concrete subst when the enclosing fn itself
monomorphises). Without this, a polymorphic body calling another
polymorphic free fn produced a spurious __Unit specialisation
whose body referenced compare at Unit.
Roadmap split: shipped Eq/Ord half checked, Show + print-rewire half
remains pending behind the heap-Str ABI prerequisite. DESIGN.md
§"Prelude classes" amended.
One pre-existing fixture (test_22b1_missing_method) renamed its
class method ne → tne to avoid collision with the new prelude `ne`.
Bench: check.py + cross_lang.py exit 0; compile_check.py exits 1
with one sub-ms check_ms.local_rec_capture at +26% (tolerance 25%) —
prelude-growth-related noise-band fluctuation, ratifiable per spec
§248-249 and journal Concerns.
Restructure ailang-check/src/mono.rs::monomorphise_workspace into a
single specialiser over every Type::Forall-quantified Def::Fn, covering
both class-method residuals AND polymorphic free-fn call sites in one
fixpoint pass. Remove the codegen-time specialiser (lower_polymorphic_call,
module_polymorphic_fns, mono_queue, mono_emitted, emit_specialised_fn,
plus the now-dead helpers apply_subst_to_term, descriptor_for_subst,
type_descriptor) entirely. Codegen sees only monomorphic Def::Fns after
this iter — no polymorphic call sites, no codegen-time queue.
Architecture changes:
- MonoTarget: struct → enum with ClassMethod / FreeFn variants; dedup
keys are guaranteed-disjoint via 'class'/'free' first component.
- collect_mono_targets: new FreeFnCall channel through synth (cleaner
than the plan's separate-walker proposal — one less data flow,
substitution tracking comes 'for free' via fresh metavars +
post-synth subst.apply). Plan Step 4.4 (polymorphic_free_fns env
field) consequently obsolete.
- synthesise_mono_fn_for_free_fn: new free-fn entry point; substitutes
rigid vars in BOTH the type AND the body (body substitution required
because free-fn bodies carry inner Lams whose param_tys reference
outer Forall vars — adapted from plan's 'body unchanged' sketch).
- mono_symbol_n: N-ary extension of mono_symbol; bit-stable for the
single-type-var case (hash-stability pin Task 1 fires zero times
through all eight refactor tasks).
- rewrite_class_method_calls → rewrite_mono_calls; interleaved-slot
collector preserves the positional-cursor invariant across both
channels.
- workspace_has_typeclasses → workspace_has_specialisable_targets
(principled correctness; old predicate happened to already be true
for every user workspace because the prelude is auto-injected).
Codegen cleanup:
- Two call sites of lower_polymorphic_call deleted (codegen/src/lib.rs
lines ~1939-1945, ~1965-1973).
- lower_polymorphic_call body, module_polymorphic_fns field +
population + Emitter wiring, mono_queue / mono_emitted, drain loop,
emit_specialised_fn — all removed.
- is_static_callee collapsed to module_user_fns-only.
- subst.rs apply_subst_to_term + descriptor_for_subst removed; synth.rs
type_descriptor removed (all dead post-removal).
- ail emit-ir command pipeline gains lift_letrecs + monomorphise_workspace
pre-passes (pre-iter-23.4 the codegen-time poly path was masking
this dependency — emit-ir is now consistent with build).
- Net codegen reduction: -285 lines lib.rs, -93 lines subst.rs.
Tests:
- mono_hash_stability.rs (new): regression pin for six primitive Eq/Ord
mono-symbol body hashes; stayed bit-stable through all eight refactor
tasks.
- mono_unification.rs (new): six tests covering variant-key disjointness,
free-fn target emission, free-fn synthesis with rigid substitution,
rewrite walker on free fns, identity for poly-free-fn-only workspaces,
end-to-end cmp_max_smoke runtime correctness.
- typeclass_22b3.rs: three test sites updated to MonoTarget::ClassMethod
enum form.
- 73 e2e + 18 typeclass + 81 codegen tests all green workspace-wide.
DESIGN.md §'Monomorphisation (post-typecheck, pre-codegen)' amended:
two-arm fixpoint described, disjoint-keyed dedup, cursor-aligned
walker, removed codegen-time path.
Bench check (all exit 0, 112 metrics stable): bench/check.py +
compile_check.py + cross_lang.py.
Plan parent: docs/plans/2026-05-11-iter-23.4.md (fab1685).
Spec parent: docs/specs/2026-05-11-23-eq-ord-prelude.md (841d65d).
Per-iter journal documents two adapted deviations from the plan
(synth-channel vs separate walker; body substitution; emit-ir fix);
no spec defects.
The auto-loaded prelude (iter 23.2 work-in-progress) injects
`class Eq` plus three primitive instances (Eq Int, Eq Bool, Eq Str)
into every workspace. Five workspace::tests assertions broke against
this new baseline:
- iter22b1_missing_method_fires_diagnostic
- instance_without_superclass_instance_fires
- instance_overriding_nonexistent_method_fires
Their fixtures redeclare `class Eq` (and `class Ord` in one case),
which now collides with the prelude. Renamed each fixture's
`Eq`/`eq` -> `TEq`/`teq` and `Ord`/`lt` -> `TOrd`/`tlt`, matching
the scheme already used in the two earlier-renamed test_22b2
fixtures. Method `ne` stays (does not collide). Assertion strings
in workspace.rs updated to match.
- iter22b1_workspace_with_no_classes_has_empty_registry
- iter22b1_instance_in_class_module_loads_clean
Their asserted registry counts assumed an otherwise-empty registry.
Rewritten to filter by `defining_module != "prelude"`: the property
is "no NON-prelude entries" / "exactly one fixture-owned entry",
not raw count.
Doc comments updated alongside each assertion change so the rationale
for TEq/TOrd (collision avoidance) is local. No production code
touched.
`monomorphise_workspace` re-runs `synth` on every fn body to recover
residual class constraints; the env it uses is built by
`mono::build_workspace_env`, which delegates to `build_check_env` and
produces a workspace-flat `ctor_index` (every Def::Type ctor across
every module, keyed by bare ctor name → bare type name).
`check_in_workspace` (lib.rs:1247-1258) explicitly clears that flat
index after `build_check_env` and rebuilds it per-module so that
`Pattern::Ctor`'s local-first / imports-fallback resolution at
lib.rs:2486-2521 keeps the qualified-type-name comparison at
lib.rs:2526 intact: imports-fallback yields a qualified
`resolved_type_name` (`Mod.Type`), local-hit yields a bare one.
The mono pass never does the per-module overlay, so when a body in
module B pattern-matches a ctor `C` whose Def::Type lives in imported
module A, the workspace-flat index resolves `C` locally and yields the
bare type name. The scrutinee, however, was typed against the
qualified name, and the comparison fails with
`PatternTypeMismatch { ctor: "Cons", ty: "A.Type<...>" }`.
Surfaced by iter 23.2 Task 3, which adds `class Eq a` + Eq Int/Bool/Str
instances to the prelude. Pre-Task-3 the prelude is class-free, so
`workspace_has_typeclasses(ws) == false` and the mono pass early-outs
at `mono.rs:73`. Task 3 flips the gate; every workspace now traverses
bodies, which brings the latent bug to the surface for the
pre-existing `nested_ctor_pattern_first_two_sum` and
`std_either_list_demo` E2E tests.
Sibling regressions in the same family: `mono_xmod_qualified_ref.rs`
(env.imports not seeded), commit 13b36cc (env.globals not seeded for
self-recursive fns), commit 5c5180f (env.types / env.ctor_index not
seeded for user ADTs — the original "flat ctor_index" decision that
this bug now exposes as wrong-by-construction for cross-module ctor
pattern resolution).
The minimal fixture is two modules with five defs total:
test_mono_ctor_listmod (data List a = Nil | Cons a (List a)) and
test_mono_ctor_main (class Trivial a + instance Trivial Int + a fn
that pattern-matches Cons against the imported List<Int> + a main).
The test pins the inner cause: matches against the specific
`CheckError::PatternTypeMismatch` variant with the qualified
scrutinee type and bare ctor name, so it stays RED regardless of the
prelude's typeclass content.
Hypothesis-driven measurement of "did monomorphisation actually
buy us performance?" on a 100M-iter LCG hot loop, AILang mono'd
code vs. four C reference variants (direct-inlinable, direct-
noinline, indirect-monomorphic, indirect-polymorphic). Zen 3,
clang -O2, median-of-15.
Headline: H1 supported, but the mechanism is inlining, not
dispatch shape. AILang mono = hand-C direct (1.000x). Indirect-
monomorphic = direct-noinline (1.000x) — saturating branch
predictor makes the indirect-call cost vanish on this hardware.
Inlining is the actual 3.31x win; polymorphic indirect adds
another 21% predictor-miss penalty.
DESIGN.md Decision 11 gains a rationale paragraph reframing mono
as inlining-enabler rather than indirect-call-eliminator, with
explicit pointer to the bench. JOURNAL entry records the full
methodology, ratios, limitations, and the side-effect mono-pass
env.globals-seeding bug surfaced while building the AILang fixture
(separate RED-first debug iter to follow).
Adds three end-to-end tests for the 22b.3 mono pass, each with a
matching one-property fixture under examples/. Defends mono-pass
invariants 3, 4, and 6 from docs/specs/2026-05-09-22-typeclasses.md
at the binary level (stdout-asserting, not AST-asserting):
- coherence_two_instances_pick_correct_body_at_runtime — class R
with instances at Int and Bool, both reachable from one main.
Stdout `11\n22` proves both mono fns are synthesised AND each
call site picks the matching body (no collapse).
- class_default_method_runs_and_prints_default_value — empty
instance body + class-level `default` clause must lower, link,
and print the default value (`99`). Promotes the existing
synthesise_mono_fn unit test to a binary-level guarantee.
- cross_module_class_method_runs_and_prints_correct_value —
class+instance in module A, called from module B's main. The
qualified-name rewrite + cross-module synth-def placement was
AST-tested in 22b.3.6; this pins down the emit-and-link path.
All 18 typeclass_22b3 tests pass; full workspace green; 3 bench
gates 0/0/0.
Four new E2E tests in typeclass_22b2.rs covering invariants the
per-task fixtures (all single-module, single-fn) did not exercise:
- cross_module_class_method_resolves_and_fires_no_instance:
module B's call to `show` (declared in module A) reaches the
no-instance arm, proving Env.class_methods is merged workspace-
wide and not restricted to the local module.
- cross_module_polymorphic_fn_without_constraint_fires_missing_constraint:
same merge guarantees the missing-constraint arm sees the residual
produced by a call to A's class method from inside B.
- cross_module_instance_satisfies_concrete_call: the workspace
registry built at load time over all modules must populate keys
visible from B; a concrete call resolves clean cross-module.
- two_fns_each_missing_constraint_produce_two_diagnostics: pins
check_in_workspace's per-def aggregation — two ill-formed fns
produce two diagnostics (one per fn), not one.
Six new fixtures (xmod_* trio + two_fns_*).
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.
Adds seven fixtures under examples/test_22b1_* exercising the
workspace-load coherence checks plus four positive/negative tests in
ailang-core/src/workspace.rs:
- iter22b1_instance_in_class_module_loads_clean: positive case;
test_22b1_orphan_class.ail.json declares Show + instance Show Int
in the same module (the class's). Registry has one entry.
- iter22b1_orphan_instance_fires_diagnostic: declares Show in
test_22b1_orphan_third_classmod, declares instance Show Int in
test_22b1_orphan_third (a third module). Fires OrphanInstance.
- iter22b1_duplicate_instance_fires_diagnostic: per the JOURNAL hint,
module A defines class Show + instance Show MyInt (legal, A is
class's module), module B defines type MyInt + instance Show MyInt
(legal, B is type's module). Entry imports both. Fires
DuplicateInstance with first/second_module distinct.
- iter22b1_missing_method_fires_diagnostic: class Eq with two
non-default methods (eq, ne), instance Eq Int specifies only ne.
Fires MissingMethod { method: "eq" }.
The surface round-trip gate (ailang-surface/tests/round_trip.rs)
filters out test_22b1_* fixtures because the Form-B parser arms for
ClassDef/InstanceDef are deferred to 22b.4. Without the filter, every
fixture's printed text would re-parse-fail on the unknown `class` /
`instance` head.
Test count: 291 → 295 (4 new workspace tests, all green).
Closes the apples-to-apples gap from 21'e. Adds:
- examples/bench_list_sum_explicit.ailx — same algorithm and sizes
as bench_list_sum, fully (borrow)/(own)/(drop-iterative)
annotated so codegen emits proper inc/dec instrumentation.
- bench/reference/list_sum_explicit_free.c — same algorithm
with explicit free() walking the chain after sum.
The full alloc+dec vs malloc+free comparison reveals two non-
trivial conclusions:
1. AILang's full RC pipeline is only 26% slower than glibc
malloc+free on this workload (rc/c = 1.26x). The implicit-
mode comparison's 1.42x was misleading — it counted neither
pipeline's free path. The fair ratio is 1.26x, materially
better than the previous read.
2. RC's dec is cheaper per cell than glibc free(). AILang
dec-tax: ~3 ns/cell. C free-tax: ~5.5 ns/cell. Plausible
cause: ailang_rc_dec operates on a known-shape cell with a
fixed-offset refcount and a static per-type drop fn — no
free-list bucketing, no header introspection, no global lock.
bump's advantage expresses fully: bench_list_sum_explicit.bump/c
= 0.42x means AILang at bump is 2.4x faster than C malloc+free.
Sets a useful upper bound on a slab/pool RC allocator's potential.
The 21'-family arc — bench-regression infrastructure — is now
substantively complete: 21'a (bench/check.py), 21'b (corpus
widening), 21'c (compile_check.py), 21'd (pure-compute fixtures
+ harness hardening), 21'e (cross-language hand-C), 21'f (explicit
apples-to-apples). 63 runtime metrics + 18 compile metrics + 25
cross-lang metrics under regression coverage. Any future iter
that regresses any axis beyond tolerance gets caught at the next
family close.
Remaining queue is back to substantive language work — Family 21
(typeclasses / polymorphic ADTs at runtime / pattern-binding
generalisation) is now an orchestrator-level fork that needs
direct user input.
Closes the third corpus blind spot (heap-allocation-only) by
adding two fixtures with no allocation pressure: bench_compute_
intsum (tail-recursive integer accumulator) and bench_compute_
collatz (Collatz step-counter, branchy).
Surprise on intsum: 50M-iteration loop runs in 1ms wall under
all three allocators. LLVM's induction-variable analysis applies
the closed-form triangular-sum reduction to AILang's IR — a
positive codegen finding (the IR composes with LLVM's optimizer
at the same level a hand-C loop would) but it makes intsum
useless as a runtime regression bench. Excluded from run.sh's
fixtures array; kept in examples/ as reference and as a future
cross-language comparison anchor.
Collatz survives optimization (data-dependent control flow). At
56ms wall, gc/bump/rc all within 2% — the canonical "pure-compute
is allocator-invariant" data point this fixture is meant to
prove. If a future codegen change leaks an allocation into the
inner loop, the 1.00x / 1.02x ratios diverge visibly.
Two infrastructure fixes the new fixtures forced:
- 6-decimal precision in run.sh's Python timing helper and median
averager (was 3-decimal; sub-ms times rounded to 0.000 and
crashed the ratio awk with Division durch Null).
- Zero-guard in the ratio awk (defensive even with the precision
bump, since LLVM-eliminated workloads can still hit zero).
Latency baseline: implicit_at_rc.max_us tolerance 25% -> 30%.
Three captures today (477 / 456 / 609 µs) show natural run-to-run
dispersion wider than the original tolerance accounts for. Not a
softening to dodge regression — the original baseline was the
first capture; a fairer tolerance across natural max-of-1000-
samples width is what the harness needed from the start.
Baseline file: 47 -> 55 metrics. 21'e (cross-language reference,
clang -O2 hand-C ratios) is the natural next dispatch.
Two new throughput fixtures targeting blind spots in the 21'a
corpus:
- bench_closure_chain exercises the build_pair_drop_fn codegen
path (the 18c.4 doubled-braces trigger). Each iteration of
run_loop allocates a {thunk, env} closure pair via the
let-rec-name-as-value escape route. Sizes 10k / 100k / 500k.
rc/bump = 4.14x — materially worse than the 2.91x / 2.59x of
the linear/tree fixtures, exposing that closure work pays the
RC alloc tax twice (pair + env-struct).
- bench_hof_pipeline exercises poly-ADT instantiation and
indirect dispatch via fold_with_fn over List<a>. Sizes 100k /
1M / 3M elements. Ratios essentially match bench_list_sum,
confirming the 13b static-template-plus-ctor-inline design
has zero measurable overhead at this scale.
Baseline file extends from 31 to 47 metrics. The two new fixtures
build clean under all three allocators; the rc-arm build exercises
the per-type drop fn for the closure-pair, providing a tripwire
for any future 18c.4-class IR malformedness.
JOURNAL records both surprises (4.14x closure tax, ~zero HOF/poly
overhead) and explicitly notes the dispersion observation on
explicit_at_rc.p99 — three captures today (357.5 / 294.6 / 251.5)
confirm wide run-to-run variance on that fixture. Methodology
upgrade (n>=10 captures or tighter fixture) deferred to 21'c.
bench/run.sh fixtures array updated. bench/check.py needed no
changes — its parser handles the wider table by metric name.
reuse-as: render `(reuse-as src body)` as `reuse src as body` with
adaptive braces — inline for single-line bodies (the 99% Ctor case),
braced for multi-line (Let, Seq, nested Match). Reads as English
subject-verb-object instead of compound keyword + always-block.
let-inlining: `let x = rhs; <body using x once>` collapses to
`<body[x := rhs]>` when (a) rhs is not a `Term::Do` (keep effect
sequencing visible), (b) x is used exactly once (no work duplication),
(c) rhs renders single-line AND ≤ 40 chars (no line smearing). Lossy
projection — round-trip mediator sees the original .ail.json and can
re-introduce a let when the mode model demands it.
Helpers `count_free_var` and `subst_var_with_term` are render-local;
both respect inner shadowing (let, lam, match arm pattern binders,
let rec). Pre-render value at current level + check for newline + len
budget; on inline, write_term_prec gets passed parent_prec so the
substituted term still wraps correctly inside binops.
Snapshot drift: rc_app_let_partial_drop_leak.prose.txt — boilerplate
`let p = build_pair(1)` collapsed into the match scrutinee. Improves
readability. Cons-tower in rc_own_param_drop kept its let thanks to
the length budget (52 chars > 40).
Tests: 59 unit (+ 9 new) + 4 snapshot, all green. Coverage:
inline-single-use, two-uses-keeps, zero-uses-keeps, Do-rhs-keeps,
multiline-rhs-keeps, length-budget-keeps, shadowing-not-counted,
reuse-as inline + braces.
Eleven binary builtins (+ - * / % == != < <= > >=) render as
lhs op rhs when called with two args (tail-flagged keeps prefix).
Standard Rust-aligned 4-level precedence table elides parens.
not(x) renders as !x. Long /// doc strings wrap at 80 cols on
word boundaries.
bench_list_sum: 'if ==(n, 0)' becomes 'if n == 0', '+(acc, h)'
becomes 'acc + h', tail keyword still visible on tail calls.
19 new unit tests (47 total). 4 snapshots (3 re-rendered + 1 new
bench fixture). Public API unchanged.
Brummel