A tagged value reaching a transport consumer from a DEREF, CAST, or
UNWRAP source materialized as ONE scalar word — the N_UN(STAR) arm's
localloadop pulled word0 (the tag) and every cursor consumer then
transported garbage payload (cs pushed stale DX, ww stored 0/garbage;
divergent asm AND silent-wrong on both stages — ken f35 asm proof +
ken37v D3a/D3b). Consumers × sources × sizes all wrong: arg push,
let-init, assign, return, match scrutinee, as, widen — from *p at
16/24/32B, from identity/widening tagged casts, and from `?`/`!`
whose success variant is itself tagged (nested box: payload words
dropped). `is` and ww-match-16B passed only by stale-register luck.
Fix extends the #37 mem-based machinery (26d3754) below the 32B cap
instead of re-deriving:
- cg_tagged_memread/taggedmemread: an N_UN(STAR) deref of a
non-nullable tagged box is mem-based at ANY size — the pointer
value IS the box address. The N_UN emitter skips the scalar load
(joins the TY_FN/TY_ARRAY value-is-address skip); the existing
size-generic memread arms in widen-store/match/as pick the source
up unchanged, `is` loads the tag through the address.
- arg push: the memread fatal becomes the mem-based push (words
high→low from (AX)) — closes#35's word0-only push and wires the
33-48B INDEX/DOT loud as a side effect. Pop side drains via
pushargsrev's returned word count, unchanged.
- cg_tagged_castpeel/taggedcastpeel: tagged→tagged casts are
transport-transparent; peel at the call-arg widen decision and the
widen-store entry so the ident/deref arms see the carrier and the
remap keys on the operand type. The identity-only subset
(cg_tagged_idcastpeel) applies at is/as/match, which key variant
indices on the scrutinee's own type; surviving non-identity casts
die LOUD there and at the widen cursor arms (rule 7) instead of
word0 garbage. The peel also wires 929's >48B memarg same-type
cast row (place resolves post-peel; loud pin flips to a run row).
- tryprop/tryunw: IDENT sources load the cursor from their slot,
memread sources from the box address (≤32B); >32B non-call and
global tagged idents die loud (rule 7). A TAGGED success variant
shifts the nested box past the outer tag (twin of the #241 tuple
shift) — closes the unwrap-source half (ken unw16).
- wwstage alignment UP to the cstage type-keyed routes:
rhstaggedabicall admits N_UN deref + N_TRYPROP/N_TRYUNW (stamped
type), matchscrutt carries the N_UN stamped type (spill size +
variant indices; was nil → tag-0 clamp + mis-sized spill),
cgreturn routes memread sources through the widener (the
fall-through wrapped the un-deref'd POINTER as payload), and
pushargsrev's aistagged gate admits the deref kind.
Emitters and consumers ship as ONE commit: they share the memread
contract, and splitting opens a transient window where a wired
emitter hands an address to an unwired consumer — the #61/#37
route-sharing fuse. The test flips ride along because they pin the
flip itself: 941's two #37 deref loud-symmetry pins become run rows
(the loud is now wired), 929's fail_rvalue_cast becomes
memarg_idcast_peeled.
No-drift bar held: ≤32B IDENT/INDEX/DOT sources emit byte-identical
asm vs master 4c46d3a (probe corpus nd1: ident let/match/arg,
struct-field, indexed element, call, nullable, ident-widen — both
stages IDENTICAL); is-on-deref is incidentally byte-identical too
(the tag load moved from the emitter to the consumer).
Tests: 941 grows 252→272 checks — ken's exact f35/D3a/D3b shapes,
each consumer × source × size cell (16/24/32/56B, str + struct
payloads), neighbor-guard row, identity-cast arg, widening-cast let
(payload checked — the old cs pass was is-only luck), success-first
unwrap-to-tagged + ident/deref unwrap, the 56B slice-deref let+match
flips (payload-pinned), and 2 rule-7 loud pins (global tagged `?`,
cast-to-third-union). Reviewer-C rows commit ken's remaining
adversarial shapes (gC1 deref-wrapped cast arg, gC2 void-variant
deref, gC3 slice-element-pointer deref, gC6 56B memarg-leg deref arg
— that one a regression pin, already place-resolved at base), a 40B
deref ARG (the 33-48B mem-push leg, silent word0 at base), and a
multi-arg pop-balance row (tagged-deref arg mid-list, called twice —
the original #35 1-push-2-pops symptom). At base 4c46d3a the impl
rows fail 53/254 (silent-wrong exits, cs≠ww asm, missing louds); the
reviewer rows kill at base too (flip rows LOUD, others wrong-exit)
except the gC6 pin. At HEAD 272/272 + 929 22 rows + test-unit 284.
Residuals (filed separately, pre-existing): #216 success-tag
divergence — error-FIRST unions emit CMPQ $1 (cs s_tag) vs CMPQ $0
(ww first-param) and ww's first-param success-type read misses the
tagged shift; match-expr tagged yield is cstage-checker-rejected
while ww runs it (the #34/#43 acceptance family); `as` binding a
STRUCT payload at let-init stays loud ("aggregate init from unhandled
rhs shape"); wwstage tagged-source arg-widen-into-WIDER-slot (the
pushargsrev #21-comment out-of-scope boundary, task #55) — the deref
leg of that family is now cstage-correct via the widen-store memread
arm but stays wwstage-silent-wrong (joins the pre-existing INDEX leg;
ident leg runs by prefix-luck under-push); truncating scalar cast as
a box payload drops the conversion (task #56, both stages, untouched
by the peel — scalar→scalar casts are never peeled).
Hojun-Cho
322667b820