The wwstage checker walked a match's raw AST variant list and never expanded a ...inner spread variant, so it rejected fmt's match over field = (...formattable | *mods) ('not a variant of scrutinee'). cstage's resolve_type flattens the spread at type-build. Mirror that in the AST exhaustiveness walk (casevariantin + a recursive checkvariantcovered): when a variant resolves to N_TTAGGED via a spread, recurse into its members. Additive + spread-gated -- typeeqast / casevariantpairmatch (#13) / casecovers untouched, so non-spread matches and 990-997 byte-id are unaffected. Also size a spread N_TTAGGED off each flattened member (mirror cstage check.c), dropping the inner union tag word (field 40B to 32B). Closes the #209 CHECKER reject; full fmt-byte-id still awaits cgen cluster #226 (io.read nominal-remap) + #227 (spread-widen ABI), so fmt tests stay cstage-only with retargeted comments. Adds test 792; regenerates w6c/wwdump combined.ww.
The Option-C parallel _v vstream API was scaffolding to bring the io stack up alongside the old surface; carrying both permanently is a rule-9 divergence from ref/hare, which has exactly one io surface. Collapse onto that surface (stream = *vtable, ref/hare/io/stream.ha) and rename the _v symbols to their Hare names (io vstream->stream, fmt vfprint->fprint, bufio/memio/log surfaces, log.new). Deletes the 4 lib/*/vstream.ww scaffold files; regenerates w6c/wwdump combined.ww. cstage and wwstage stay byte-identical and combined_ww_fresh holds; all 220 tests pass.
The #94 Option-C vstream surface was left incomplete and structurally
divergent from Hare: constructors heap-allocated and returned (X | nomem)
or used out-params instead of Hare's by-value stack ownership; memio lacked
reset/buffer/borrowedread; bufio's scanner was never ported to the vtable.
This is the additive half of the eFinal collapse — OLD surface stays fully
live; the destructive FLIP (delete OLD + drop _v + repoint) is the next
commit.
Reshape all constructors to VALUE-RETURN (field-by-field sret; the heap +
nomem was an unnecessary crutch — wide slice-bearing struct return-by-value
is byte-id-proven, cf 925_sret_struct_return_run). memio fixed/dynamic/
dynamicfrom, bufio init, log new now return the struct by value; the nomem
is gone with the alloc that forced it.
memio: unify the per-flavour ctx structs onto one `stream` (vt at offset 0);
collapse fixed_string + dynamic_string into a single string() over the common
header (bare-str return is the ratified rule-9 frombytes carve-out, cited at
the site per ref/hare/memio/stream.ha:81); port reset/buffer/borrowedread as
single fns over the header.
bufio: collapse the EXISTING scanner subset (newscannerbuf/scanbyte/scanbytes/
scanline/finish + setflush/flush/unread/isbuffered) onto the vtable, with src
now io.vstream so reads go through io.st_read. The Hare scanner functions ww
never implemented (scanrune/scanstring-arbitrary-delim/readtok/readline/
auto-grow newscanner) are out of scope and deferred to #217 — eFinal is a
collapse, not a feature expansion.
Keep the explicit (&fn): *io.T casts on vtable-slot stores (cgen-neutral;
avoids the #214 (X|void) over-acceptance surface; dropping the casts is a
deferred #206 payoff gated on #214).
Self-gate: 776 (memio) 18/18 and 778 (bufio) 27/27, every row carrying a
cs.s == ww.s byte-id check — bufio/fmt/log are not compiler-embedded, so
these rows are their only byte-id coverage. 779/781 stay STAGE_CS-only
pending #209. Regen w6c+wwdump combined.ww (io+memio are the embedded
modules).
Adds bufio_vstream + isbuffered_v alongside the pre-vtable
bufio.init / bufio.isbuffered surface, mirroring fold-e2's
lib/memio and fold-e3's lib/fmt parallel-API shape. The OLD
bufio.ww surface stays untouched; fold-eFinal (#50) atomically
flips the package shape, drops the `_v` suffix, and retires the
legacy callbacks.
bufio_ctx wraps an underlying *io.stream (OLD API) — bufio_vstream
src parameter type stays *io.stream until io fold-2 lands
`handle = (file | int)` (drew-deferred). vt is the first field
for the intrusive vstream→*bufio_ctx cast, same shape as
memio/fmt vstream wrappers.
Sibling task filed:
#210 struct-lit slice-typed field silently drops under
alloc(T{slice = val})?. Parallel to #207 for slice fields;
scalar/ptr fields in the same alloc-struct-lit populate
correctly. Workaround: post-alloc field-assign
c.slicefield = val. Documented inline; drops out on close.
Other deferrals retained inline: #206 cast wrappers (3 vtable
wire-up + 2 isbuffered_v comparand), #173 nomem-widen for the
io.closed → io.error boundary, #207 alloc-zero-chain for vt.
bufio is not embedded in any selfhost combined.ww (test-only);
no Makefile regen needed (#110-blind safe).
test/wcc/778_bufio_vstream_run pins the 5-row scenario set:
write+flush, read+refill, isbuffered_v discriminator, OLD/NEW
boundary check, and a branched-callee #105 row. cs+ww+byte-id
green on all 5 rows.
make test: 211 passed (was 210).
