Hojun-Cho
26724feefb
Phase 1 of Rob's two-phase A.6.3f pattern: populate the variant
chain in `tinfofornode`'s TTAGGED arm so phase 2 (#50b) can retire
`nullable_ptr_tag`'s AST-keyed walk in cgenutil onto a tinfo read.
Per b8e5a92 (A.6.3b) commit body: "nullableptrtag stays AST-keyed
for now — tinfofornode doesn't populate TY_TAGGED.params … so the
tinfo equivalent of cstage cgen.c:405 nullable_ptr_tag can't read
params today."
Restructure the TTAGGED arm into a single pre-pass: walk `n.list`,
resolve each variant via tinfofornode, alloc `tparam{name="",
type_=vt, tnext=nil}`, link head/tail, accumulate maxsz + al
inline. Set `r.params = head` after the loop. AST-level nullable
fold runs after, before size assignment — kept AST-keyed (not
ported to cstage's tinfo-level `kind==TY_VOID && !iserror` check)
because wwstage tinfo carries no `iserror` field; that's an honest
data-shape divergence (filed in passing as part of #13's TTAGGED
normalization arc).
Mirrors cstage cmd/wcc/check.c:347-435 — same head/tail append-
list construction, same Tparam reuse across struct-fields /
tuple-fields / fn-params / tagged-variants (sea-of-stars per
rule 12 — one record, four consumers, no per-kind variant of
the param node). Diverges from harec's array+id-sort at
ref/harec/include/types.h:128-132 / ref/harec/src/type_store.c:
431-432; rule 10 anchors wwstage byte-id to cstage, not harec.
Purely additive: ti.params has zero readers on TY_TAGGED today
(typeeq walks params only for TY_FN/TY_TUPLE; cgenutil's
nullableptrtag is still AST-keyed; #50b will consume). Byte-
identity (994/995) unchanged at 133/133 — pre-impl risk audit
by ken-thompson came back zero, confirmed by full make test.
A latent divergence wwstage doesn't cover (never-drop /
...spread / dedup / single-variant collapse — see cstage type
set normalization at check.c:393-432) is pre-existing and out
of #50's scope; tracked as #13. Phase 2 nullableptrtag is a
linear walk for the first TY_PTR variant in a 2-variant
nullable, indifferent to ordering and dedup, so it does not
need #13 closed first.
Net +12 LOC per file across check.ww + two .combined.ww
bundler regens.
112 KiB
112 KiB