Hojun-Cho
eea3e197c2
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.