The wcc test drivers ran `ww build <bare-/tmp src>` with no -o, so the
compiler's <stem>.sepwork scratch landed beside the source and was never
cleaned: unbounded /tmp growth (2195 stale dirs observed) that fills tmpfs
and fabricates phantom test failures + silent harness aborts, and for
in-repo fixture builds leaked .sepwork into the tracked tree.
Each leaking build now writes its source + output inside a per-invocation
tmpdir, passes -o <tmpdir>/<stem> so the .sepwork lands inside it, and
rm -rf's the tmpdir on every exit path -- including fopen-fail and the
expected-fail reject builds (scratch is mkdir'd before the build can fail).
`ww run` and explicit-`-o`/byte-id helpers are left as-is; the 990/993
byte-id comparison logic is byte-for-byte unchanged.
Two items filed separately (this commit holds the no-Makefile / no-main.c
rail):
- #13: a stale <src>.s byte-id readback (749) silently no-ops since
separate-compile emits .s to <ostem>.sepwork/__root.s; documented inline.
- #14: build-system Makefile recipes build selfhost/cmd/*/main.ww with no
-o and leak main.sepwork in-tree (bounded, gitignored; own commit).
One concern -- sepwork leak hygiene -- across 228 drivers; uniform
transform applied per-file and two-round reviewed. make test: all 402
passed, zero net-new /tmp scratch, zero test-driven in-repo .sepwork.
A widening sub-union cast (return/let `v: inner` into a union whose member
is the nested `inner`) skipped the nested widen arm and emitted tag=0 (a
2nd-variant value returned the wrong payload). cstage loud-stops #35;
wwstage now matches: cgwidentaggedstorebp louds on the subset cast, and
cgreturn routes genuine-widening tagged returns (rhs TY_TAGGED, ru1!=fu1)
through the widener choke-point so the same loud fires. Same-type returns
stay on the proven passthrough. Faithful inner-tag->outer-index remap
deferred. test/wcc/835 S1 row.
isassignable's untyped-int arm fell through *confident=false/return true,
silently accepting an untyped int into a union whose variant is itself a
nested (non-flattened) union; ww emitted tag=0 (wrong arm) where cstage
louds. Reject unless a direct variant is numeric-or-enum (N_TENUM accept
mirrors cstage type_isnum). Faithful flatten+rebox deferred (nominal
identity, post-CSP). test/wcc/835 (new) + Makefile.
