docs: session handoff 2026-10-08 (L7 done, language work, generics inc1)

docs/session-handoff-2026-10-08.md

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+# Session handoff — 2026-10-08
+
+Branch **`generics-inc1`** (off `ast-stage-c`).  Working tree clean.
+
+Current state: **suite 189/189**, **FIXPOINT OK (3,490,054 bytes)**.
+
+## Where the branches/tags stand
+
+- `ast-stage-c` — the L7 refactor + language work (tags below), HEAD
+  `0f611c0 docs: GOTO/labels landed`.
+- `generics-inc1` — `ast-stage-c` + Increment 1 of generics, HEAD
+  `55d2e7c docs: generics inc1 status + inc2 plan`.
+
+Tags on `ast-stage-c` (chronological):
+`v3-lower7-flip`, `v3-lower7-decoupled`, `v3-lower7-complete`,
+`v3-fix-arrrecfield`, `v3-arrrecfield-complete`, `v3-status-2026-10-08`,
+`v3-composite-results`, `v3-chain-calls`, `v3-goto`.
+
+## What this session did
+
+**L7 refactor — done.**  Lower is the only emitter; the inline emit was
+deleted from statements, control flow, declarations,
+expressions/designators, calls and `ProcHeading`.  Found and fixed a
+latent **VAR-actual note-ring bug** (`RestoreSession` now clears the
+ring).  Swept dead code (0 unreferenced procs).  Retired `-lower` and
+the degenerate byte-compare tests (suite 204 → 181).
+
+**Language / correctness work (all on `ast-stage-c`):**
+- **array-of-record inline length words** — small arrays expand inline,
+  large ones get a generated **run-time init loop** (`t_arrrecfld`,
+  `t_arrrecbig`).
+- **statement-context result suffixes** (`F()^.x := e`, `t_stmtsfx`).
+- **composite function results** (record/array/set, sret) — which also
+  fixed **methods with local variables** (their block decls were never
+  stored); `t_retrec`, `t_retmeth`.
+- **class results + chained post-call method calls** (`F().M()`,
+  `t_chain`).
+- **`GOTO`/labels** — required splitting `Design` into
+  `Design` + `DesignTail` to resolve the LL(1) label/designator clash;
+  `t_goto`, `t_gotobad`.
+
+**Docs refreshed:** `STATUS.md`, `analysis_gaps.md`, `features.md`,
+`analysis_generics.md`.
+
+## Generics (the active thread)
+
+Syntax chosen: **ISO 10514-2** generic modules + refinement
+(`../Generics/m2generic-syntaxe-analysis.md`).
+
+**Increment 1 — done (`e1d0472`).**  Grammar recognition of the four
+module categories:
+`GENERIC DEFINITION/IMPLEMENTATION MODULE M (E : TYPE); …` and
+`DEFINITION/IMPLEMENTATION MODULE X = M(actuals); …`.  Formals are
+unresolved alias types (`SymTab.EnterTypeParam`); refinements are
+recorded.  A refinement still yields an **empty** module.
+
+**Increment 2 — the next step.**  Instantiate by **re-parsing the
+generic source with a substitution scope**, driven by a driver session
+pre-pass:
+1. record each generic's def/impl **file path** when parsed;
+2. on a refinement, re-open the generic, bind formals to actuals, name
+   the module `X`, dedup, and lower it **before** the importer;
+3. move the normal body's `BeginDef` into the `;` branch so the
+   refinement does not pre-register `X`; add
+   `SymTab.EnterTypeParamBound`; add a grammar instantiation context
+   (`instActive`/`instName`/`instActual`) + accessors
+   (`IsGenericUnit`, `IsRefinementUnit`, `GetRefinement`,
+   `SetInstantiation`); add the driver re-parse logic.
+
+Details and the full plan are in `docs/analysis_generics.md` (top note).
+
+## Also still open (from `docs/STATUS.md` / `analysis_gaps.md`)
+
+- L7 item 7 (delete `SaveSession`/`RestoreSession`/`SetNoEmit`) —
+  blocked on the grammar's last suppressed writers; low payoff.
+- **Library holes** (device/IO framework, `docs/wip/chanconsts.*`,
+  `streamfile.*`).
+- **Robustness**: `M2` exits 0 on errors / aborts on a missing input
+  file; weak error recovery; fixed table limits.
+- The latent **size-sensitive V3 miscompile** (removing `ASTDUMP` from
+  `M2.atg` breaks the fixpoint).
+- Generics increments 3–4 (multiple/const params, proc params,
+  constraints, `GENERIC CLASS`).
+
+## How to resume
+
+```sh
+cd compiler && ./build.sh && ./run_tests.sh   # 189/189
+cd .. && bootstrap/fixpoint.sh                # FIXPOINT OK
+git log --oneline -5
+```