A spread whose source was not a local ident fell PAST the spread arm:
cstage continued into the single-value stores with the N_SPREAD node
(garbage store), wwstage silently SKIPPED the value entirely — a silent,
cs!=ww-divergent miscompile (append(ys, f()...): cs exit 0 / ww exit 144,
want 3), reachable for every element kind and predating #34 for scalars.
Both stages now rule-7 loud-stop the shape (deferred, task #37).
Also pins the widener's already-tagged single-value source path
(tagged_ident_src row, i64 + bool members) and adds the
spread_call_loudstop BUILD_FAIL row — test 800 is now 15 rows / 43
fixtures.
Hojun-Cho
36be9f469d