Completes plan 2 Tasks 7-8. owner.ml: mutable-value-semantics flow analysis
producing the four plan-3 emitter tables (moves, drops incl. LIVE-MASK for trap
unwinding, rc with elision, residual borrow sites) plus WO-E301-304 two-site
diagnostics. Alias questions run over canonicalized places, so a double-mut
reached through let-bound aliases lands in the residual table like the direct
form; dump.ml's contract notes the emitter must coalesce guards per operand.
main.ml: directory discovery, cross-file programs (symbols merge before bodies
check), diagnostics ordered by (file,line,col), new WO-E214 for a name declared
in two files. New docs/plan/oop-vm/01-error-catalog.md (14 emitted + 10 reserved
codes), un-ignored so both plan tracks can cite it; justfile regains woc-*.
builtin_scalars is now the five that work: Int, Bool, Text, Timestamp, Id.
Money/SKU/Float and the abstract_types allowlist are gone — `abstract` never
lexed, and Float had no literal syntax and no wob kind, so no value could exist.
Fixtures and samples retype Money->Int, SKU->Text. The abstract newtype feature
is rejected outright (verdict row adopt->reject); haxe-parity Task 7 keeps `is`.
nullable-types-implementation.md corrected: ?T is plumbed but UNENFORCED
(E211-213 declared, never emitted; probe exits 0), handed to haxe-parity Task 6
as next work item. Records all 10 dead codes incl. E205 — interface satisfaction
is unchecked. crates/rt keeps its Money/SKU fixtures (opaque strings, Stage 2).
Gate: build warning-clean, 14 + 264 checks 0 failures, pricing golden exit 0,
docs/examples histograms unchanged (13/70, zero WO-E225).
- ast.ml: Added Nullable variant to field_ty; param.ty/method_sig.ret/method_decl.ret now use field_ty
- parser.ml: Parse ? prefix for field types, return types, parameters
- dump.ml: Render ?T in --dump-ast output
- types.ml: New typechecker (Task 6) with nullable field-kind derivation (WO_K_NULLABLE=6)
- dune: Added types module
- Added golden test fixtures for nullable types and statement/expression parser
- Added implementation plan doc
