Brummel
600565d356
Additive producer-side work for the typed-MIR milestone (spec
docs/specs/0060-typed-mir.md), surfaced while building the mir.1b
codegen-consumption switch. Nothing here consumes MIR — codegen is
untouched; the whole existing suite stays green and one new RED pin
goes green. The mir.1b codegen switch itself stays in the working tree.
Headline fix — own-ADT type-arg localization in free-fn mono:
monomorphise_workspace's free-fn arm normalises every observed
type-arg through Registry::normalize_type_for_lookup. That
normalisation is load-bearing for cross-module dedup and a stable
specialisation symbol name, but it qualifies a *defining-module-own*
ADT to `<module>.<T>`. synthesise_mono_fn_for_free_fn then substitutes
those qualified type-args into the polymorphic source signature and
body, which are in the module's own *bare* convention (the qualify
pre-pass deliberately leaves own-module type-cons bare — lib.rs:4358,
"the current module sees its own types bare"). The result is a
self-inconsistent specialisation: e.g. fold_left specialised with
accumulator b := List<Int> minted
((std_list.List<Int>, Int) -> std_list.List<Int>,
std_list.List<Int>, List<Int>) -> std_list.List<Int>
— a qualified accumulator parameter against a bare list argument and a
bare Lam body. check_workspace never hits this (it synths the pre-mono
bodies, bare throughout); the old codegen tolerated it via the
now-deleted synth_arg_type's loose type-tracking. The post-mono synth
re-entry in lower_to_mir does full unification and correctly rejects
it: `expected std_list.List<Int>, got List<Int>`.
Fix: localize_own_types (mono.rs) strips the `<defining_module>.`
prefix back to bare for the module's own ADTs, applied to the type-args
before they are substituted, so the synthesised signature and body stay
uniformly bare-own. The *stored* type_args remain normalised, so the
symbol name and the Phase-3 rewrite-cursor key on the same canonical
form — the byte-identity invariant between synthesis and rewrite is
untouched. The ClassMethod arm needs no analogue: it already
substitutes the un-normalised target.type_ (mono.rs:841).
Alternatives rejected: (a) drop the normalisation in the shared
apply_subst_and_normalize helper — breaks cross-module dedup, mints
duplicate specialisations under divergent names. (b) Make
lower_to_mir's synth treat `<owner>.T` and bare `T` as equal during
unification — papers over the producer inconsistency in the consumer
and contradicts the established own-types-stay-bare invariant the rest
of check relies on. (c) Qualify the whole synthesised def own->qualified
— fights lib.rs:4358 and would require the lower path to also flip,
cascading the convention change through synth.
Producer completeness (additive, mirrors existing guards):
- lower_module skips Type::Forall defs (lower_to_mir.rs), mirroring
emit_module's guard. Polymorphic defs are stale source kept for
round-trip; their bodies carry mono-rewritten call names for
specialisations that were never synthesised, so a synth re-entry
would hit UnknownIdentifier.
- lower_module lowers non-literal const bodies to typed MTerm, carried
in MirModule.consts (+ MirConst in ailang-mir). A non-literal const
(e.g. a List ctor expression) needs a typed body once the consumer
walk takes &MTerm; literal consts emit a global and need no body.
- MirModule gains `ast: Module`, populated by lower_module — forward
scaffolding the mir.1b codegen consumption reads for module
structure. Populated here, consumed by the in-tree switch.
Verification: full `cargo test --workspace` green (697 passed, 0 failed)
with the codegen-consumption switch stashed out, including the new pin
crates/ailang-check/tests/lower_to_mir_ty.rs::poly_free_fn_accumulating_into_own_adt_elaborates
(RED before the localize fix with the exact mismatch above, GREEN after)
and the full e2e corpus (the own-ADT-poly demos elaborate clean and run
through the old codegen). This proves the producer fix is
regression-free and the remaining 22 e2e reds in the working tree are
codegen-consumption defects, not producer defects.