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.
Pre-existing landmine surfaced by #5 (whole-STRUCT N_ASSIGN). Both
stages' N_DOT dispatch gated on `lhs->lhs->kind == N_IDENT`; the
parser produces N_UN(STAR, IDENT(p)) for `(*p).f`, so both sides fell
off:
- Write side (cgassign N_DOT base): emitted nothing, store dropped.
- Read side (case N_DOT pointer-auto-deref): cgexpr derefed the
pointer as a scalar, AX = first qword of struct, field offset
dropped.
Fix: retarget base / dot_lhs to the inner IDENT when shape is
N_UN(STAR, IDENT). The existing via_ptr branch fires identically to
`p.f`. v1 scope is bare-IDENT inner only; `(*expr).f` (non-IDENT
pointer expression) is tracked separately as task #19.
702 covers 7 rows: write_i64/i32/str, read_i64/i32/str_len, roundtrip
