Structural half of the inference pass, additive — it backs `woc --dump-gc`
and does NOT yet feed field-kind derivation (that is Phase 2 at the
Types.is_gc_class seam), so no emitted bytecode or golden changes.
- compiler/src/gcinfer.ml: build the class-reference graph (edges from
Scalar/Multi/Map fields, unwrapping ?; ref and backlink contribute NO edge),
run Tarjan SCC, classify any class in a non-trivial SCC or with a self-loop
as `gc`, else `owned`; carry a cycle-path reason.
- --dump-gc mode in bin/main.ml (mirrors --dump-owner) + usage line + dune.
Verified:
- docs/examples/gc-cycle -> `Node gc (cycle Node -> Node)`, `Segment owned`.
- docs/examples/employee -> Department/Employee both `owned` (ref/backlink
make no edge, so no false cycle) — the load-bearing correctness case.
- just woc-test 566/0 (goldens untouched, build clean both flavors).
Remaining Phase 1: a --dump-gc golden fixture (deferred — verified manually to
avoid golden-harness churn this slice). Phases 2-4 per the plan.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>