fieldsize selected the slot-padded byte width of a struct field's
type-AST via the same TBANG/TNAME/TPTR/TSLICE/TARRAY/TTAGGED walker
shape slotsize used pre-#48 — with TNAME branching into
structlookup, enumlookup, and aliaslookup to follow the AST chain
back to a primitive size or struct totsize. After A.6.2 stamping
+ #48's slotsize collapse, the same data is reachable through
the populated tinfo:
TY_STRUCT / TY_ARRAY → ti.slotsize
TY_TAGGED / TY_SLICE / TY_STR → ti.size
TY_PTR / TY_FN / TY_CHAN → 8
primitives + TY_ENUM + TY_TUPLE → ti.size (catch-all > 0)
fallback → 8
cstage SSoT is `f->type->size` at cmd/w6c/cgen.c:1386, :1656, :2515,
:2535 — wwstage routes through ti.slotsize for composites (the
#48 verdict centralizes the slot-pad rule on tinfo) and through
ti.size where natural width and in-struct width coincide.
Two latent behavior fixes ride alongside the collapse, both
cstage-parity and dead-in-bootstrap (995 byte-id is the regression
gate, currently green at 133/133):
- TY_TUPLE-typed struct field: old walker had no TTUPLE arm and
fell through to 8; cstage `f->type->size` reads the natural
sum (e.g., 24 for `(i64, str)`). New code reads ti.size,
matching cstage.
- !T-typed struct field: old walker had no TBANG arm and fell
through to 8; cstage iserror-passthrough returns the inner
type's size. tinfofornode strips N_TBANG (check.ww:1154-1161)
so the new dispatch sees the inner ti directly.
No fixtures in selfhost exercise either case today; both fixes
are pre-correct for future code that does.
Body went from ~47 LOC to ~16 LOC. `c: *cgen` retained unused for
callsite stability (slotsize / localloadop precedent, a828c03 /
68219a1). Two callsites in cgenutil.ww:1870 + cgenexpr.ww:3594
untouched.
Dot-chain helpers (dotinnerstructptr, dotfieldtnode,
dotchainresolve) are split off as #49b — they walk a cgen-side
`structinfo` table keyed by field name + offset, and tinfo.fields
is not yet populated by check.ww's TSTRUCT/TTUPLE arms. Parallel
structure to #50's TY_TAGGED.params gap; treat as a separate
populate-then-port pair.
Net -48 LOC across cgenutil.ww + two .combined.ww bundler regens.
Full make test green at 133/133.
Hojun-Cho
883665e962