# Next session — plan

**Branch state (2026-10-18):** `master` and `resolve-check` are both at
`95ca4d6` (merged, fast-forward) and pushed to `origin`.  Work on
`master`.

**Baseline:** suite **239/239**, fixpoint **OK (3,812,771 bytes)**,
corpus **405/612, 0 crashes**.  The corpus harness resolves transitive
imports (method from 2026-10-18).

**Policy:** follow **Modula-2**, not gm2 degradation — declaration
before use (only a `POINTER`'s base may forward-reference).  In
`docs/gaps/`, the `decl-order` and `gm2-ext` classes are **not targets**;
the 44-file "undeclared identifier" bucket is inflated by them.

---

## P0 — generics: two instantiations of one generic (real bug, do first)

Instantiating one generic twice with arguments from different families
fails on the second instantiation:

```mod
GENERIC DEFINITION MODULE GStack (T : TYPE);
TYPE NodeRec = RECORD val : T; next : Node END; ...
```

`GStack(CHAR)` alone works; `GStack(INTEGER)` alone works; together,
the second fails (`incompatible assignment` at `n^.val := v`).
`INTEGER` + `CARDINAL` appears to pass only because the stale binding
still type-checks.

**Likely culprit:** `SymTab.EnterTypeParamBound` returns early when the
formal is already visible, so the first instantiation's binding sticks:

```mod
IF Lookup(name) AND (SymKind(name) = KindType) THEN RETURN TRUE END;
```

*Steps:* five-file repro (generic def/mod + two instantiations + a
program); make the substitution per-instantiation (fresh alias); add a
regression test with two distinct scalar families; keep the fixpoint
green.

## P1 — quick, bounded corpus wins

- **`gap22` `__FILE__`/`__LINE__`** (`packed`, +1).
- **`gap09` scalar actual → `ARRAY OF BYTE`** (`aochar`,
  `arrayofbyte`, `bytearray`, +~3).

## P2 — structural

- **`gap12`** variant records: empty arms, `ELSE`, untagged inner
  `CASE` (5 files).
- **`gap11`** bare procedure value as a statement.
- **`gap10`** `VAR`-param type leniency (decide whether to adopt gm2's
  same-size rule — non-standard).
- **`gap13` remainder**: de-reserve the *standard* builtins (`ORD`,
  `CHR`, `VAL`, …) — contextual-keyword parser refactor (`ORDL` is done).
- **`gap18`** set-typed `CASE` labels.

## P3 — conformance remainder (architectural)

Forward references to module-level **variables/procedures** from a
procedure body still work (the two-phase parse defers bodies).  Strict
declaration-before-use would require order-aware body checking; high
risk, touches self-hosting.  The declaration part is already strict.

## P4 — latent correctness

The **size-sensitive V3 miscompile** ("removing `ASTDUMP` breaks the
fixpoint") is still unroot-caused.  Dedicated bisection session; a real
correctness landmine.

## P5 — housekeeping

- Consolidate `docs/summary_*.md` (see `docs/INDEX.md`).
- (Merge of `resolve-check` → `master`: **done**.)

---

## Gates for every step

`compiler/build.sh` → `compiler/run_tests.sh` (must stay 100%) →
`bootstrap/fixpoint.sh` (**byte-identical**) → `corpusx.sh` (record
OK/CRASH + note) → update `docs/gaps/` + `STATUS`/`README` → commit with
a `v3-*` tag.

## Resume

```sh
cd .../m2compiler-V3
git checkout master
cd compiler && ./build.sh && ./run_tests.sh   # 239/239
cd .. && TMP="$PWD/.scratch/fixpoint" ./bootstrap/fixpoint.sh
M2FLAGS="" ./.scratch/corpusx.sh              # 405 OK, 0 crash
```

**Recommendation:** P0 first (a real defect), then two P1 wins, and
reserve a separate session for P4.