A rejected program emits no .s, so the test-lang-byteid (T2) gate cannot
cover wwstage-reject -- yet the retired C twins asserted that BOTH stages
reject with the same diagnostic. runww's //ww:error arm was cstage-only,
so migrating reject rows onto it would silently drop the wwstage-reject
coverage the C twins carried.
Run w6c_ww (wwstage) alongside w6c (cstage) on each //ww:error case and
require both to fail with the shared diagnostic body present. The body is
identical across stages; only cstage's leading prefix differs, so the
substring matches the body alone (no file:line). An ERROR row now reports
PASS dual / FAIL cstage / FAIL wwstage. w6c_ww resolves off the same $BIN
as the C twins -- no new harness threading.
Two pilot reject cases (runww_dup_main_reject, runww_dup_type_reject)
exercise the dual-stage path; the wwstage leg is proven non-vacuous (a
cstage-rejects/wwstage-accepts case reports FAIL wwstage).
Prerequisite for migrating fold-3 reject rows onto runww.
Per the tier+stage split (USER-approved): the routine wwstage-behavior
run is redundant -- T2 byte-id (cstage.s vs wwstage.s, strictly more
sensitive) plus T1's cstage run together cover both stages. Drop the
wwstage path from runww; cstage==wwstage convergence moves to a separate
pre-push byte-id tool (T2). Update the test-run target comment to match.
First piece of the Go-model test rebuild: runww.ww is a ww program (the
test/run.go analog) that drives compiler cases through BOTH stages and
asserts behavior/diagnostics. Directives //ww:run / //ww:run-exit N /
//ww:error "<substr>" / //ww:compile; spawn+stderr-capture lift the
driver's procrun (main.ww:160) + dup2(2). The //ww:error check requires
rc!=0 AND the diagnostic substring (the #20 non-vacuity guard -- a crash
can't pass), and a malformed error directive fails loudly.
Bulk corpus migration + ww test wiring are follow-up folds; case spawns
need os.envp() (#28) and per-pid /tmp paths (#29) first.
