Indexing through a pointer-to-array auto-derefs, so esz and the element
classification must come from the pointee array's ELEMENT (cstage
idx_eff semantics, cgen.c:1163). Two halves of one root class:
A (wwstage-only, cs!=ww, cstage runtime-correct): elemsizeofc's #270-2
nested-array block treated an N_TPTR pointee-array like a [N][M]T outer
index and returned the whole-array size — every p[i] read/write/
compound scaled by N*size(T), and the same wrong element belief reached
the store-width chooser (var-idx write emitted an N*8B aggregate copy
sourced at the 8B rhs slot: caller-frame smash, the siphash round()
corruption). Fixed via two wwstage choke-points mirroring idx_eff:
idxeffti (tinfo: NAMED peel + TY_PTR->TY_ARRAY drill; feeds elemsizeofc
and elemissignedc/elemisfloatc/elemisf32c) and idxelemtn (node: element
tnode with the same drill; feeds every cgindex/cgassign/nodeisstr/
match-scrutinee elemtn resolution).
B (BOTH stages identically wrong, byte-id-BLIND): the TK_AMP &base[i]
arm read bu->sub->size without the ptr peel (&p[3]-&a[0] = 96, not 24).
cstage now routes esz through idx_eff.
A and B are FUSED by the pre-existing routing topology, not by choice
(rule 11): wwstage's TK_AMP arm already reads its esz via elemsizeofc
(selfhost/cmd/wcc/cgenexpr.ww:4095, the #11 addr-of twin of the #10
cgindex fix), so fixing A's choke-point flips wwstage's half of B in
the same stroke. A standalone A leaves &p[i] transiently cs!=ww;
B-first is the mirror transient; carving the TK_AMP caller out of the
fixed choke-point to preserve the wrong stride for one commit would be
a deliberate known-wrong intermediate (rule-7, vetoed by rob). One
choke-point, two enrolled routes — un-fusable without a red
intermediate.
Close-by-construction proof-grep (both stages): every remaining raw
sub->size index-stride read is TY_ARRAY-gated, a slice-only builtin
(delete/insert), a checker-stamped element tinfo (indexresult already
decays *[N]T, check.ww:2277-2284), or a non-index context (tuple
slots, let-init elements). Two true residuals filed with site+symptom
instead of silently absorbed: N_SLICE through *[N]T does not decay
(LOUD type error, Hare divergence; team task #18) and non-ident
cast-expression index bases keep wwstage's 8B-default esz (pre-existing
#74-style cluster; team task #19). cstage's N_INDEX read-side
str/slice header gates also move from u->sub to esub (identical for
every non-ptr-to-array base; honest for *[N]str — pre-fix BOTH stages
were runtime-wrong there, differently).
949_ptrarr_index_run pins the class at runtime + byte-id: {1,2,4,8}B
elems, const+var idx, param/local/cast bases, read/write/compound,
neighbor guards, &p[i] pointer-difference, siphash-round mix shape.
989_lib_byteid: siphash_test graduates #59.7 DIVERGE -> ID (ratchet
tripped loud pre-update; no other #59.x pin flipped in the same run).
(*p)[i] (sub-bug C) follows separately.
The 990-997 gates byte-id only the selfhost-embedded modules; every
other lib/ module compiled cstage-only, which let regex.finish ship
cs≠ww for weeks (task #21, FC0). 989_lib_byteid compiles each lib test
fixture's resolved unit (plus import-probe stubs for the fixtureless
sort/path/endian/net/hash/fnv/crypto.math/c.libc) through both stages
and byte-compares the asm: 28 units pinned byte-identical (incl.
lib/regex), 12 known divergences + 3 wwstage front-end rejects pinned
as documented-allowed with task #59 cites — a landed fix trips the pin
and demands graduation, so the corpus can only ratchet toward ID.
Two rot-guards, both review-driven: each probe carries a sentinel that
must appear in the resolved unit (the driver silently skips an
unresolvable import, so a dropped probe would byte-id an empty main —
green while covering nothing), and a corpus-completeness scan fails
loudly on any lib/ dir not enrolled, so new modules cannot ship
uncovered.
Compile+cmp only (no driver run, no source-tree writes): phase-1
parallel-safe, ~6s.
