Brummel
76b21c00eb
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 (dfdc65f) introduced — it shipped red on that
commit. Resolver taught the dual-link form, mirroring its sibling.
Verification: cargo test --workspace = 731 passed, 0 failed (twice,
stable); e2e 102 passed, no binary exits non-zero (corpus crash-free);
grep-clean for Implicit/fn_implicit/mode_eq across crates; every drop
fix confirmed via emitted IR + AILANG_RC_STATS balance on the head==K,
head!=K, and Nil paths. Three BLOCKEDs en route (the unsound first
husk-dec attempt, the over-strict derivation premise, the leg-B fix
direction) were each treated as a real design/spec gap and rediagnosed,
not patched over.
Supersedes #54 (return-position-only leak patch). Precondition #57
(linearity hardening) was already met. Spec docs/specs/0062, plan
docs/plans/0121.
closes #55
79 lines
2.7 KiB
Plaintext
79 lines
2.7 KiB
Plaintext
; Bench fixture (Bench iter): balanced-tree build + sum.
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;
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; Allocates a balanced binary tree of `Node value left right` cells,
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; then walks it summing the value field. Distinct from
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; `bench_list_sum` in two ways:
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; 1. Each tree node has an additional pointer field versus a list
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; cell — 32-byte alloc instead of 24-byte. The branching shape
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; means the recursion structure is genuinely tree-shaped: the
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; build cannot be made tail-recursive without explicit
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; continuation passing, so this fixture is constrained to depths
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; where the recursion stack fits.
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; 2. The traversal pattern hits two children per node, exercising
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; the GC's mark-phase pointer-chasing heuristics differently from
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; a plain linked-list walk.
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;
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; Depth picked: 20 -> 2^20 - 1 = 1_048_575 nodes -> 32 MB heap usage.
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; Recursion depth in `build_tree` and `sum_tree` matches `depth`,
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; which fits comfortably in the default 8 MB system stack.
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;
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; Hardcoded multi-call form: build/sum the same tree thrice for
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; signal averaging. The depths are different per call so the GC has
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; to deal with three independent live-set sizes.
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;
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; Expected stdout (one int per line):
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; depth 16: 2^16 - 1 = 65535 nodes, sum = 65535
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; depth 18: 2^18 - 1 = 262143 nodes, sum = 262143
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; depth 20: 2^20 - 1 = 1048575 nodes, sum = 1048575
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;
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; (Each node stores literal `1`; sum is therefore node count.)
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(module bench_tree_walk
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(data Tree
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(ctor Leaf)
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(ctor Node (con Int) (con Tree) (con Tree)))
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(fn build_tree
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(doc "Balanced binary tree of given depth, every value = 1.")
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(type
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(fn-type
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(params (own (con Int)))
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(ret (own (con Tree)))))
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(params depth)
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(body
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(if (app eq depth 0)
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(term-ctor Tree Leaf)
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(term-ctor Tree Node
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1
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(app build_tree (app - depth 1))
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(app build_tree (app - depth 1))))))
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(fn sum_tree
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(doc "Sum every Node value via match recursion. Constructor-blocked: not tail-recursive, but recursion depth = tree depth so fits.")
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(type
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(fn-type
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(params (own (con Tree)))
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(ret (own (con Int)))))
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(params t)
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(body
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(match t
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(case (pat-ctor Leaf) 0)
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(case (pat-ctor Node v l r)
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(app + v (app + (app sum_tree l) (app sum_tree r)))))))
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(fn run_one
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(doc "Build a tree of given depth, sum it, print the sum.")
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(type (fn-type (params (own (con Int))) (ret (own (con Unit))) (effects IO)))
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(params depth)
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(body
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(app print (app sum_tree (app build_tree depth)))))
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(fn main
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(type (fn-type (params) (ret (own (con Unit))) (effects IO)))
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(params)
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(body
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(seq (app run_one 16)
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(seq (app run_one 18)
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(app run_one 20))))))
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