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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
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0015f3dad1 |
spec: unique binder names per fn — A2b leg of RawBuf drop-leak (refs #43)
The last open leg of the #43 owned-heap drop-leak cluster is the
UniquenessTable shadow-name collapse: the side-table keys by
(def_name, binder_name), so a fn that shadows a binder name collapses
every shadow onto one key. The outermost binding (records last, on pop)
overwrites the inner ones; codegen's scope-close drop gates then read
the collapsed consume_count for the innermost binding and suppress its
drop, leaking the owned slab.
Spec 0056 resolves this as a compiler-internal naming collision — NOT
the deeper, separate problem of persistent AST provenance back to the
authored form (certain to be needed eventually, deliberately deferred;
conflating the two is a category error). Fix: alpha-rename shadowing
binders during desugar (reusing the existing fresh-name machinery that
already mints $mp_N / $lr_N), making the (def, name) key injective
again. No consumer of the uniqueness table changes — they all key by
name, and the name becomes a per-fn injective identity. IR-neutral:
codegen names heap by fresh SSA, never by source binder name. The
pre-desugar hashed form is untouched, so module identity and hash-pin
tests are unaffected.
RED fixtures securing the binder-kind class (the user's gating
condition before proceeding to the uniform-across-kinds fix):
- Let-shadow: the three raw_buf_{int,float,bool}_shadow_rebind tests
(already in tree, committed
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