2e8dfd8ff95bb7cdd61bfa71c88a89b385c236e8
2 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Brummel
|
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 (
|
||
|
Brummel
|
c5fd16a4eb |
feat(codegen): StrRep loop-carried Str ⇒ Heap, close the #49 recur leak
mir.4 closes bug #49 (a heap-Str loop binder replaced across `recur`
leaks every superseded slab; the loop result leaks too) structurally,
by making every Str a loop binder holds OR a loop returns an owned heap
slab — then deleting the `!is_str` carve-out from BOTH codegen gates
that carried it. The leg-by-leg `!is_str` patches are gone.
Mechanism (the milestone thesis: representation in MIR, codegen reads
it). lower_to_mir sets rep = StrRep::Heap on every Str literal in a
loop-carried position; codegen's MTerm::Str arm promotes a Heap literal
via ailang_str_clone (a fresh ailang_rc_alloc slab, rc_header refcount
1). Three promotion positions, all in the Loop/Recur lowering:
1. binder seed inits (is_str_ty on the binder type);
2. recur args at Str-binder positions (read off the innermost
loop_stack frame);
3. exit-arm tail result literals (promote_tail_str_literals walks the
loop body's tail positions when the loop returns Str).
With every loop-carried Str now owned-heap, both gates lose !is_str:
the recur superseded-value dec (lib.rs) frees each intermediate slab;
the loop-result trackability gate (drop.rs:493) lets the caller's
scope-close free the final slab.
Why both gates, and the planning-time error this corrects. The original
plan/spec scoped the deletion to the recur dec gate only, reasoning the
#49 loop result is "consumed by print". The implement-orchestrator
landed that scope (Tasks 1-2) clean and correctly BLOCKED: it took #49
from live=3 to live=1, the residual being the loop RESULT. I verified
the diagnosis empirically:
- print BORROWS its arg (prelude: `(let s (show x) (do io/print_str
s))`, the eob.1 heap-Str discipline), so `(print s)` does not free
the loop result; the caller's let-binder does, via drop.rs:493.
"consumed by print" != "freed by print" — that was the error.
- Deleting drop.rs:493's !is_str takes #49 and the recur-literal
fixture to live=0.
- Deleting drop.rs:493 WITHOUT exit-arm promotion SIGSEGVs (exit 139)
on a loop returning a static Str literal — hence the third
promotion position and the static-exit witness.
The agent surfaced a real spec defect via an empirical BLOCK rather
than guessing; I corrected the spec refinement note (both gates, three
positions) and completed the loop-result leg inline, the context
already loaded from verifying the BLOCK (CLAUDE.md "already loaded
context" carve-out). drop.rs:493's Str carve-out is now sound to delete.
Boundary (asserted ill-typed, not constructible): a borrowed static-Str
Var seeded/recur'd into a consumed Str loop binder — rejected upstream
by uniqueness (a consumed binder position is owned).
Verification (orchestrator-run): all four leak fixtures reach live=0
under AILANG_RC_STATS — #49 (xyyy), recur-literal (reset), static-exit
(result), and the
|