Reading or writing a tagged field of an indexed array element
(xs[i].field) was broken on BOTH stages, byte-identically and
silently (#263 gate-blind): the arr[i].field branches had arms for
array/str/slice/float but no TY_TAGGED arm, so the tagged field fell
to the single-word scalar path. READ loaded only the tag word (stale
payload -> `xs[i].min as T` read garbage); ASSIGN stored the raw
unboxed scalar into the tag slot, corrupting the box.
Insert a TY_TAGGED cursor arm before each scalar fallback, both
sites both stages (cgen.c read + assign; cgenexpr.ww cgdot N_INDEX-lhs
read + cgassign indexed-field). READ mirrors cg_tagged_memread
(payload -> DX/CX/R8, tag -> AX last). ASSIGN synthesizes the tag for
the concrete variant (taggedvariantindext) and stores tag+payload via
the str/slice 3-word store spine -- not the source-remap widener
(concrete rhs has no source tag to remap).
>32B / multi-word / float payloads are loud-stopped at all four arms
(emission not yet wired; see #114). That shape is reachable today via
a narrow-variant ctor, so it louds rather than silently miscompiling.
Both stages get the same arm -> byte-id preserved (990-997 green; the
runtime is the net for this #263 class). Pin 944_idx_tagged_field_run
(read/assign runtime rows + >32B expect-loud rows).
Hojun-Cho
351abb0ab3