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2 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Brummel
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76b21c00eb |
feat(lang): eliminate the Implicit ownership default — totality + the drop-soundness it demasks (#55)
Deletes `ParamMode::Implicit`. `ParamMode` is now `{Own, Borrow}`:
every fn-type slot on every signature carries an explicit `own` or
`borrow`, no defaulted position survives anywhere (model 0008 §2,
spec 0062). The parser rejects a bare fn-type slot; `borrow-return`
and `borrow-over-value` reject at the signature; the corpus is
migrated to minimal-ownership modes (consumed ⇒ own, read-only-heap
⇒ borrow, value ⇒ trivial-own). The documented `Implicit`-ret-mode
leak is fixed: an owned heap return now drops exactly once (live=0,
acceptance criterion 5).
This was the easy half. Removing the default ACTIVATED a family of
drop paths that `Implicit` had silently skipped — the pre-cutover
language was leaking (and in places mis-dropping) here rather than
crashing, because an Implicit scrutinee turned the drop off. Making
the modes explicit (Own) turned those paths on and exposed two
latent-bug clusters, all fixed RED-first as part of this cutover:
Drop-soundness family (four legs):
A. lit-sub-pattern double-free — the desugar re-matched the same
owned scrutinee in the lit fall-through; fixed by grouping
consecutive same-ctor arms into one match (bind fields once),
in ailang-core desugar.
B. Cons-husk leak on non-tail arm bodies — the lit-sub-pattern
desugar rebound the owned scrutinee via `Let $mp = xs`, which
bumped consume_count and suppressed the existing fn-return
partial_drop. Fixed by not rebinding a bare-Var scrutinee
(one husk-freeing mechanism, not two).
C. polymorphic `drop_<T>` rc_dec'd monomorphised value fields —
the per-ADT drop fn was emitted once from the polymorphic
TypeDef, defaulting type-var fields to ptr and rc_dec'ing
inline Ints (segfault). Fixed with per-monomorph drop
functions (new ailang-codegen::dropmono): the drop set is
collected from the lowered MIR, value-type fields are skipped,
heap fields still freed once; monomorphic-concrete ADTs keep
their byte-identical un-suffixed drop symbol.
D. static Str literal passed to an `(own Str)` param — the
literal lowers to a header-less rodata constant; the callee's
now-active rc_dec read its length field as a refcount and
freed a static address (segfault). Fixed with the missing
fourth StrRep::Static→Heap promotion in lower_to_mir's App arm,
gated on Own mode (borrow args stay static, no regression).
over-strict-mode lint over-fired: it suggested `(borrow V)` for
value-typed params (which `borrow-over-value` rejects — own is the
only legal mode there) and fired on `(intrinsic)` bodies (whose
consumption the linearity walk cannot observe). Tightened to skip
both; contract 0008 updated to the narrowed firing scope.
Irreversible step — canonical-form hash reset (model 0008 §6,
acceptance criterion 6). Every signature now carries explicit modes,
so the hashable canonical JSON changed for every module. RATIFY:
the corpus-wide hash-pin reset (hash_pin, prelude_module_hash_pin,
mono_hash_stability, eq_ord_e2e, embed_export_hash_stable, the
ct4/iter*/loop_recur schema-extension pins) and the list ir_snapshot
golden were regenerated once, deliberately, as the intended one-time
consequence of removing the mode elision from the canonical form —
not a regression. Each regenerated hash verified deterministic across
two runs.
Also fixes a pre-existing latent failure surfaced by the verification
gate, unrelated to this cutover: the `every_contract_names_a_resolvable_
ratifying_test` resolver (design_index_pin) could not resolve the
" + " dual-link ratifying-test form (`uniqueness.rs + linearity.rs`)
that the #57 audit-close (
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Brummel
|
feb941363a |
bugfix: print leak — propagate ret_mode through rigid substitution
`(app print x)` under --alloc=rc leaked the heap-Str allocated by
`show x` in print's body: the let-binder `s` in
`(let s (app show x) (do io/print_str s))` was never flagged
trackable, so the drop site at scope-close emitted no
`ailang_rc_dec(s)`. Minimal repro `(body (app print 42))` produced
`allocs=1 frees=0 live=1`.
Root cause is two-layer:
1. examples/prelude.ail.json declared the Show class method `show`
without an explicit `ret_mode` on the return type, so serde
defaulted to ParamMode::Implicit. Fix: add `"ret_mode": "own"`
on the Show.show method, parallel to how the heap-Str-producing
builtins (int_to_str, bool_to_str, float_to_str, str_clone,
str_concat) declare it. examples/prelude.ail regenerated via
`ail render` to stay parse-isomorphic with the JSON.
2. crates/ailang-check/src/lib.rs `substitute_rigids` was silently
stripping `param_modes` and `ret_mode` whenever it rebuilt a
`Type::Fn`, so even after the prelude fix, the mono-synthesised
`show__Int / Bool / Str / Float` lost the `Own` annotation
during rigid substitution. Fix: preserve both fields through
the substitution.
RED pin: crates/ail/tests/print_no_leak_pin.rs (test
`alloc_rc_print_int_does_not_leak_show_result_str`) + fixture
examples/print_int_no_leak_pin.ail asserts allocs == frees and
live == 0 for `(body (app print 42))` under --alloc=rc.
Ten mono-body hash pins re-recorded (eq__Int/Bool/Str,
compare__Int/Bool/Str, show__Int/Bool/Str/Float, eq__IntBox) —
the bodies are semantically identical; the canonical JSON now
carries the previously-stripped mode metadata, so the body hash
moves. Re-pinning is bookkeeping for the intentional drift, not
a workaround.
Surfaced 2026-05-14 during the rpe.1 BLOCKED orchestrator run
(Cat A). Existed in latent form since iter 24.3 (when Show + print
shipped); only became user-observable when `(app print ...)` joined
the corpus. cargo test --workspace: 565 / 0 / 3.
Open follow-up flagged for next /audit: grep for `Type::Fn { ..., .. }`
field-spread sites — any other shape that drops modes during
rebuild is a latent instance of the same bug class. Out of scope
for this minimal fix.
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