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 f7f4c3b) — assert live == 0.
- Flat-pattern-shadow: a differential test plus its two fixtures
(flat_pat_shadow_leak.ail shadows the outer binder; _control.ail
alpha-renames it to a distinct name). The shadow must reach the
control's live count. Differential by design, to isolate the
shadow-collapse drop from unrelated baseline drop gaps out of
#43's scope.
Grounding-check PASS; ail-check parse-gate green on every fenced block.
Brummel
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