Every surviving carrier now owns its artifacts: checked mkdir/mkdtemp/
fopen acquisition, one all-exit cleanup funnel per carrier, ENOENT-
tolerant checked unlinks, exact-path deletion (rm -rf only for an
owned pid-keyed dir or a .sepwork beneath one), and cleanup failure
fails a passing carrier without overwriting its diagnostic. In the
same pass the carriers adapt to the driver contract this branch lands:
--sep and WW_PKGCACHE are gone, -S and the /tmp/ww_run_<pid> scratch
contract are asserted, and rows whose runtime or reject coverage moved
to test/wcc/data fixtures or test/lang @test owners are trimmed to the
byte/artifact/diagnostic observations only they can make.
Repair and adaptation ride together because most files interleave both
in the same hunks; splitting would manufacture intermediate carrier
states that never existed and cannot run against either driver.
wwstage's slotsize() shared its TY_STRUCT arm with TUPLE/ARRAY and
returned ti.slotsize — the SUM of the slot-padded field widths. For a
struct LOCAL that over-reserves the frame slot whenever a field is a
sub-8 nested composite: a nested inner{x:u8,y:u8} (size 2, slotsize 8)
pads its in-struct footprint, and the local inherits that pad. cstage
has no slotsize SSoT — it reserves the local at f->type->size, the
checker's NATURAL r.size (cmd/w6c/cgen.c). So on outer{a:u8,
p:inner{x:u8,y:u8}, z:i64} wwstage emitted frame $32 / struct-base
-24(BP) while cstage emitted $16 / -16(BP): a uniform -8 BP shift on
every field access. Both stages exit 0 (each self-consistent), so it is
runtime-invisible — but it is a cs!=ww .s divergence (rule 10) and a
latent byte-id gate-landmine the day such a struct enters the corpus.
Same dual-SSoT leak as #44 (field-OFFSET) / #55, one notion over:
struct-local-slot-SIZE.
Fix: split the TY_STRUCT arm out and return round8(ti.size). The TUPLE
arm (8B/elem slot, user ruling #60) and the ARRAY arm (element stride,
#48 [N]Alias 24B) keep ti.slotsize — those are deliberate, ruled
divergences and are untouched. The struct-local slot consumers
(cgendecl.ww letslotsize via cglet, cgenstmt.ww) all flow through this
arm; si.totsize (registerstruct → structabisize / global-emit) is a
separate consumer and is not this path.
CLASS-N corpus-neutral: every corpus struct local is 8-aligned, so
round8(ti.size) == slotsize for all of them and the w6c_ww/wwdump_ww
emission does not move (994 byte-id on 18 corpus inputs + 995 5-tool
self-rebuild both green post-fix). 989_structlocal_frame is the
FRAME-ABSOLUTE proof (w6c vs w6c_ww .s byte-diff; nested3 + tail_u32 +
flat control) — the .s twin of the runtime 989_nestfield_run, which
deliberately does not gate the frame and points here for it.
