The #259 store fix unmasked a pre-existing latent cs!=ww in the tagged-
element READ via an N_DOT base (`x.o[i]`) / chained N_INDEX base
(`m[i][j]`): wwstage materialized the element as a SCALAR one-word load +
zeroed tag where cstage copies the full tagged slot — silently dropping
the tag/payload-high word (wrong variant). Three sites all keyed off the
same N_IDENT-only gate; cstage classifies TY_TAGGED for ANY base off the
checker-stamped element type. Align wwstage UP:
- cgindex (cgenexpr.ww): the N_DOT/N_INDEX-base arm now sets
elem_tagged/elem_slot_sz from n.type_ (the stamped element tinfo),
mirroring cstage cgen.c:8101 — the full-slot copy arms then fire.
- rhstaggedabicall (cgenutil.ww): the N_INDEX branch reads
typeistagged(src.type_) for any base instead of an N_IDENT-only
structural lookup, mirroring cstage's src->type keying — fixes the
let-init / call-arg widen-source spill.
- forwardtagged (cgenstmt.ww): the return-path passthrough gate now
accepts N_INDEX/N_DOT tagged rhs (which cgexpr materializes into the
tagged ABI), not just N_CALL — fixes `return x.o[i]`.
read + call-arg + return + chained 2D all close by construction (one
materialization path). cstage unchanged (pure wwstage-align-up). 949
gains 9 #261 rows (i32 + explicit-void variant per shape proves the tag
survives) and flips the two #259 read-back rows to byteid=1.
Hojun-Cho
0afc272f47