The #242 tuple arm of the widen choke-point (cg_widen_tagged_store /
cgwidentaggedstorebp) gated on a BARE N_TUPLE source. The cast-to-
CONCRETE-VARIANT wrapper ((a, b): range_alias) — the only spelling
real code uses (ref/hare/regex/regex.ha:213) — is not a widen-cast
(its destination is the variant, not the union), so the peel left it
intact and it fell to the SCALAR arm: cursor word 0 stored, payload
slot 1+ silently zero-filled. Both stages, byte-id, gate-blind.
Fix at the choke-point: peel N_CAST(lhs=N_TUPLE) where the NAMED-
peeled cast type is TY_TUPLE and iterate the inner element list; the
variant tag keeps resolving from the CAST's type (exact named match),
so the #241 untyped-element loud-stop stays scoped to the bare form
on both stages.
Closure by construction needed two more arms (reviewer proof-grep):
cg_widen_tagged_push's direct-push fast path classified a tuple-typed
ARG source as scalar — pushed word 0 only AND coerced an unresolved
tag to 0 — so f(((a,b): rng)) bypassed the fixed arm entirely (and
the bare typed (a,b) arg dropped slot 1 the same way). Tuple-typed
sources now route through the scratch store. The remaining non-
literal tuple sources (ident / call result / match binding) have no
word-copy arm in the store and fell to its scalar arm — loud-stop
(rule 7) until #72 wires them. Every tagged-payload materialisation
now funnels through cg_widen_tagged_store, which handles or rejects
every tuple shape: let/assign/return/append (cgen.c:7511) directly,
arg push via the scratch route.
test/936: cast-tuple matrix (let / append local+index-place+deref-
place+ptr-field-place / ident+float+str elements / 3-member layout-neutrality /
direct-arg) + bare-form no-regress (return + arg) + bare-literal and
tuple-ident reject pins, per-row cs==ww byte-id; verified failing
24/40 at parent 8578ad0.
Unblocks regex fold-4 (charset_range_item construction).
Hojun-Cho
bb8a44a564