# raw-buf.4 — RawBuf payload + Term::New desugar — Implementation Plan

> **Parent spec:** `docs/specs/0054-raw-buf.md`
>
> **For agentic workers:** REQUIRED SUB-SKILL: use the
> `implement` skill to run this plan. Steps use `- [ ]`
> checkboxes for tracking.

**Goal:** Ship `RawBuf a` end-to-end — the `raw_buf` kernel-tier
module, its 12 scope-qualified codegen intercepts (alloc / load /
store / size over an `@ailang_rc_alloc` slab), a flat drop, and the
general `Term::New` → `(app T.new …)` desugar — so the worked
consumer program builds and prints `60`.

**Architecture:** Four tasks. Task 1 lands the `raw_buf` manifest +
`ailang-surface` wiring (checkable, no codegen yet — raw_buf's
intrinsic markers are not yet in the bijection collector's module
list, so they are simply uncollected). Task 2 lands the general
`Term::New` desugar (runs *before* check, so the type-scoped
`(app T.new …)` it produces flows through the raw-buf.3 scope
threading) and removes the two codegen `Term::New` deferral arms.
Task 3 lands the 12 intercept entries + emit fns + the flat
intrinsic-storage drop, and adds raw_buf to the bijection collector
(marker↔entry lockstep closes here). Task 4 lands the E2E + drop
leak tests. The raw-buf.3 scope-qualified mono mechanism is already
in place — RawBuf.{op}@T monos to `RawBuf_op__T`; the 12 entries are
a mechanical application.

**Tech Stack:** Rust. `crates/ailang-kernel/` (raw_buf submodule),
`crates/ailang-surface/` (parse + inject), `crates/ailang-core/src/desugar.rs`
(Term::New rewrite), `crates/ailang-codegen/src/{intercepts.rs,lib.rs,drop.rs}`
(entries + emit + drop + arm removal), `crates/ail/tests/` + `examples/` (E2E).

---

**Files this plan creates or modifies:**

- Create: `crates/ailang-kernel/src/raw_buf/mod.rs` — `pub const SOURCE: &str = include_str!("source.ail");`.
- Create: `crates/ailang-kernel/src/raw_buf/source.ail` — the gate-verified raw_buf Form-A module.
- Create: `examples/raw_buf_int.ail`, `examples/raw_buf_float.ail`, `examples/raw_buf_bool.ail`, `examples/raw_buf_reject_str.ail` — E2E + reject fixtures.
- Modify: `crates/ailang-kernel/src/lib.rs:11-13` — `mod raw_buf;` + `pub use raw_buf::SOURCE as RAW_BUF_AIL;`.
- Modify: `crates/ailang-surface/src/loader.rs:54-57, 123-143` — `parse_raw_buf` + injection.
- Modify: `crates/ailang-surface/src/lib.rs:39` — re-export `parse_raw_buf`.
- Modify: `crates/ailang-core/src/desugar.rs:926-935` — `Term::New` → `Term::App` rewrite.
- Modify: `crates/ailang-codegen/src/lib.rs:2094-2097, 3296-3299` — remove both `Term::New` deferral arms.
- Modify: `crates/ailang-codegen/src/lib.rs:1071-1090` — intrinsic-storage flat-drop guard.
- Modify: `crates/ailang-codegen/src/intercepts.rs` — 12 entries + emit fns + `parse_raw_buf()` in the bijection collector module list.
- Modify: `crates/ailang-core/tests/workspace_pin.rs:56-58` — count 4 → 5 + `contains_key("raw_buf")`.
- Modify: `crates/ail/tests/e2e.rs:870-879` — count 4 → 5 + raw_buf name.
- Modify: `crates/ailang-core/tests/design_schema_drift.rs:744+` — `raw_buf_module_round_trips`.
- Test: `crates/ail/tests/e2e.rs` (append) — `raw_buf_int_e2e`, `raw_buf_float_e2e`, `raw_buf_bool_e2e`, `raw_buf_param_in_reject_e2e`, `raw_buf_no_leak`.

---

### Task 1: raw_buf manifest + ailang-surface wiring + round-trip

**Files:**
- Create: `crates/ailang-kernel/src/raw_buf/{mod.rs, source.ail}`
- Modify: `crates/ailang-kernel/src/lib.rs`, `crates/ailang-surface/src/loader.rs`, `crates/ailang-surface/src/lib.rs`
- Modify: `crates/ailang-core/tests/workspace_pin.rs`, `crates/ail/tests/e2e.rs` (count), `crates/ailang-core/tests/design_schema_drift.rs` (round-trip)

- [ ] **Step 1: Create `crates/ailang-kernel/src/raw_buf/source.ail`.**

Write exactly (gate-verified this milestone — `ail check` → `ok`):

```text
(module raw_buf
  (kernel)
  (data RawBuf (vars a)
    (doc "Mutable, indexed, fixed-size flat buffer of primitive elements. Opaque single-ctor handle; codegen intercepts emit raw alloc/load/store over an @ailang_rc_alloc slab. Element type restricted to {Int, Float, Bool} via param-in.")
    (ctor B a)
    (param-in (a Int Float Bool)))
  (fn new
    (doc "Allocate an uninitialised RawBuf of capacity n. Compiler-supplied (intrinsic) body; codegen intercept RawBuf_new__<T> emits @ailang_rc_alloc plus the i64 size header. Element bytes are uninitialised; caller must set before get.")
    (type (forall (vars a) (fn-type (params (con Int)) (ret (own (con RawBuf a))))))
    (params n)
    (intrinsic))
  (fn get
    (doc "Indexed read. UB if i >= (size b); caller checks bounds via size. Compiler-supplied (intrinsic) body; codegen intercept RawBuf_get__<T> emits getelementptr plus load.")
    (type (forall (vars a) (fn-type (params (borrow (con RawBuf a)) (con Int)) (ret a))))
    (params b i)
    (intrinsic))
  (fn set
    (doc "Indexed write. Linear: own in, own out. Under uniqueness in-place; under shared copy-on-write (Issue #22). Compiler-supplied (intrinsic) body; codegen intercept RawBuf_set__<T> emits getelementptr plus store.")
    (type (forall (vars a) (fn-type (params (own (con RawBuf a)) (con Int) a) (ret (own (con RawBuf a))))))
    (params b i v)
    (intrinsic))
  (fn size
    (doc "Element count. Compiler-supplied (intrinsic) body; codegen intercept RawBuf_size__<T> emits a single i64 load from the slab header.")
    (type (forall (vars a) (fn-type (params (borrow (con RawBuf a))) (ret (con Int)))))
    (params b)
    (intrinsic)))
```

End the file with a single trailing newline. (`text`-fenced: `raw_buf` is injected as a reserved kernel-tier module, so `ail check` on it standalone returns `reserved-module-name`; the round-trip test in Step 7 ratifies it.)

- [ ] **Step 2: Create `crates/ailang-kernel/src/raw_buf/mod.rs`.**

```rust
//! Raw-buf submodule — the Form-A source of the `raw_buf` kernel-tier
//! base-extension module (RawBuf: a mutable indexed flat buffer of
//! primitive elements). Parsed by `ailang_surface::parse_raw_buf`,
//! round-trip-pinned by `raw_buf_module_round_trips`.

/// Source-of-truth Form-A text for the `raw_buf` kernel module.
/// Declares the `RawBuf` TypeDef (`param-in (a Int Float Bool)`) and
/// the four `(intrinsic)` ops `new`/`get`/`set`/`size`; codegen
/// supplies their bodies via the `RawBuf_op__<T>` intercept entries.
pub const SOURCE: &str = include_str!("source.ail");
```

- [ ] **Step 3: Add the `raw_buf` submodule + re-export to the crate hub.**

Edit `crates/ailang-kernel/src/lib.rs`. After `mod kernel_stub;` add `mod raw_buf;`; after `pub use kernel_stub::SOURCE as STUB_AIL;` add `pub use raw_buf::SOURCE as RAW_BUF_AIL;`.

- [ ] **Step 4: Add `parse_raw_buf` in `crates/ailang-surface/src/loader.rs`.**

Insert after `parse_kernel_stub` (~line 57), mirroring it verbatim with `raw_buf`/`RAW_BUF_AIL` substituted:

```rust
/// raw-buf.4: parse the embedded raw_buf kernel-tier base-extension
/// module bytes into a `Module`. Mirror of [`parse_kernel_stub`].
///
/// Source-of-truth: `ailang_kernel::RAW_BUF_AIL`. Declares the
/// `RawBuf` TypeDef with `param-in (a Int Float Bool)` and the four
/// `(intrinsic)` ops; codegen supplies their bodies via the
/// `RawBuf_op__<T>` intercept registry.
///
/// Panics on parse failure — build-time-validated by every drift run.
pub fn parse_raw_buf() -> Module {
    crate::parse(ailang_kernel::RAW_BUF_AIL)
        .expect("ailang_kernel::RAW_BUF_AIL must parse as a Module")
}
```

- [ ] **Step 5: Inject `raw_buf` into the workspace.**

In `load_workspace` (`loader.rs:123-132`, the block that reserves `kernel_stub` and inserts `parse_kernel_stub()`), add a symmetric block immediately after the kernel_stub insert:

```rust
    if modules.contains_key("raw_buf") {
        return Err(WorkspaceLoadError::ReservedModuleName {
            name: "raw_buf".to_string(),
        });
    }
    modules.insert("raw_buf".to_string(), parse_raw_buf());
```

(The `kernel: true` filter at `loader.rs:139-143` auto-imports it — no other change. Confirm the exact `WorkspaceLoadError::ReservedModuleName` variant + the surrounding block shape against the kernel_stub block before writing.)

- [ ] **Step 6: Re-export `parse_raw_buf`.**

Edit `crates/ailang-surface/src/lib.rs:39`. Add `parse_raw_buf` to the `pub use loader::{…}` list (alongside `parse_kernel_stub`).

- [ ] **Step 7: Add `raw_buf_module_round_trips`.**

Edit `crates/ailang-core/tests/design_schema_drift.rs`. After `kernel_stub_module_round_trips` (~764), append a mirror for raw_buf:

```rust
/// raw-buf.4: pin the JSON byte-shape of the raw_buf kernel-tier
/// base-extension module. Mirror of `kernel_stub_module_round_trips`.
#[test]
fn raw_buf_module_round_trips() {
    let m = ailang_surface::parse_raw_buf();
    assert!(m.kernel, "raw_buf is kernel-tier");
    assert_eq!(m.name, "raw_buf");
    let json = serde_json::to_value(&m).expect("serialise raw_buf");
    let recovered: Module =
        serde_json::from_value(json).expect("raw_buf round-trips through serde");
    assert!(recovered.kernel);
    assert_eq!(recovered.name, "raw_buf");
    let td = recovered.defs.iter().find_map(|d| match d {
        Def::Type(t) if t.name == "RawBuf" => Some(t),
        _ => None,
    }).expect("RawBuf TypeDef present");
    let allowed = td.param_in.get("a").expect("RawBuf.a restricted");
    assert!(allowed.contains("Int") && allowed.contains("Float") && allowed.contains("Bool"));
}
```

(Confirm the in-scope `Module`/`Def` imports + the recovered-binding shape against the existing kernel_stub test before editing.)

- [ ] **Step 8: Bump the workspace-count pins.**

`crates/ailang-core/tests/workspace_pin.rs:56-58`: change `assert_eq!(ws.modules.len(), 4)` → `5`; add `assert!(ws.modules.contains_key("raw_buf"));` after the `kernel_stub` assertion. Update the adjacent comment (`prelude`, `kernel_stub`, and `raw_buf`).
`crates/ail/tests/e2e.rs:870`: change the `modules.len()` assertion `4` → `5`; after the `kernel_stub` name assertion (~879) add a `raw_buf` name assertion mirroring it.

- [ ] **Step 9: Build + targeted test.**

Run: `cargo build --workspace 2>&1 | tail -8`
Expected: build succeeds (a dead-code warning on `RAW_BUF_AIL` is gone once `parse_raw_buf` consumes it; if Step 4-6 are complete there is none).

Run: `cargo test -p ailang-core --test design_schema_drift raw_buf_module_round_trips && cargo test -p ailang-core --test workspace_pin`
Expected: PASS — raw_buf round-trips; workspace count is 5.

- [ ] **Step 10: Full suite — manifest landed, no codegen yet.**

Run: `cargo test --workspace 2>&1 | grep -E "^test result:" | awk -F"[: ;]+" '{p+=$4; f+=$6; i+=$8} END{print "passed:",p," failed:",f," ignored:",i}'`
Expected: `passed: 671  failed: 0  ignored: 2` (670 baseline + the new `raw_buf_module_round_trips`; the count-pin edits modify existing assertions, no count change). The bijection stays green: raw_buf is NOT yet in `workspace_intrinsic_markers`'s module list (Task 3), so its 4 intrinsic markers are uncollected — no orphan-marker failure. No consumer builds RawBuf ops yet.

---

### Task 2: Term::New desugar + remove codegen deferral arms

**Files:**
- Modify: `crates/ailang-core/src/desugar.rs:926-935`
- Modify: `crates/ailang-codegen/src/lib.rs:2094-2097, 3296-3299`
- Test: `crates/ail/tests/e2e.rs` (append `new_stubt_builds_and_runs`)

- [ ] **Step 1: Rewrite the `Term::New` desugar arm.**

Edit `crates/ailang-core/src/desugar.rs`. Replace the current pass-through `Term::New { type_name, args } => Term::New { … }` arm (~926-935) with a rewrite to a type-scoped application of the type's `new` op, dropping the `NewArg::Type` element type (recovered by inference from use, per spec § Term::New desugar):

```rust
            Term::New { type_name, args } => {
                // raw-buf.4: (new T <types…> <values…>) desugars to
                // (app T.new <values…>) — a type-scoped call so synth's
                // dotted-name branch (lib.rs ~3458) resolves it through
                // the TypeDef-first ladder and the raw-buf.3 scope
                // threading mints `T_new__<elem>`. The leading
                // NewArg::Type is dropped: the AST carries no type-args
                // on App, and the element type is recovered by ordinary
                // inference from how the result is used (spec § Term::New
                // desugar). Runs before check, so no Term::New reaches
                // the type-checker or codegen.
                let value_args: Vec<Term> = args
                    .iter()
                    .filter_map(|arg| match arg {
                        NewArg::Value(v) => Some(self.desugar_term(v, scope)),
                        NewArg::Type(_) => None,
                    })
                    .collect();
                Term::App {
                    callee: Box::new(Term::Var { name: format!("{type_name}.new") }),
                    args: value_args,
                    tail: false,
                }
            }
```

(Confirm `Term::App`'s exact fields — `callee`, `args`, and the third field's name/default (`tail`?) — and `Term::Var`'s `{ name }` shape against `crates/ailang-core/src/ast.rs` before writing; mirror the existing `Term::App` construction in this file.)

- [ ] **Step 2: Remove the `lower_term` Term::New deferral arm.**

Edit `crates/ailang-codegen/src/lib.rs`. Delete the `Term::New { .. } => Err(CodegenError::Internal( "Term::New requires the type's `new` def to be desugared first … milestone raw-buf".into()))` arm (~2094-2097). The match stays exhaustive — desugar eliminates `Term::New` before codegen, so the variant is unreachable here; if the compiler now demands the arm for exhaustiveness, replace it with `Term::New { .. } => unreachable!("Term::New is desugared to (app T.new …) before codegen — raw-buf.4")` rather than an `Err`.

- [ ] **Step 3: Remove the synth-path Term::New deferral arm.**

Same treatment at `crates/ailang-codegen/src/lib.rs:3296-3299` (the sibling arm in the synth/escape path). Delete, or replace with the same `unreachable!`.

- [ ] **Step 4: Add `new_stubt_builds_and_runs` E2E (ratifies the desugar independent of RawBuf).**

`kernel_stub`'s `new` has a real `(term-ctor StubT Stub x)` body, so `(new StubT 42)` desugars to `(app StubT.new 42)` and builds. Append to `crates/ail/tests/e2e.rs`, mirroring `answer_intrinsic_builds_and_runs_printing_42` (~93) and its `build_and_run` harness. Fixture (inline string or a new `examples/new_stubt_smoke.ail`): a `main : () -> Int` that does `(new StubT 42)`, pattern-matches out the `Int`, and prints it → `42`. (Confirm the StubT field-extraction shape; the goal is only that the `(new StubT …)` path builds + runs, ratifying the desugar + arm removal.)

- [ ] **Step 5: Run the desugar ratifier + full suite.**

Run: `cargo test -p ail new_stubt_builds_and_runs 2>&1 | grep -E "test result|FAILED"`
Expected: PASS — `(new StubT 42)` builds and runs (the deferral arm is gone; desugar handles it).

Run: `cargo test --workspace 2>&1 | grep -E "^test result:" | awk -F"[: ;]+" '{p+=$4; f+=$6; i+=$8} END{print "passed:",p," failed:",f," ignored:",i}'`
Expected: `passed: 672  failed: 0  ignored: 2` (671 + `new_stubt_builds_and_runs`). All existing `(new StubT 42)` round-trip/parse tests stay green (desugar runs at check/codegen entry, not at parse — the round-trip surface is untouched).

---

### Task 3: 12 RawBuf intercept entries + emit fns + flat drop + bijection collector

**Files:**
- Modify: `crates/ailang-codegen/src/intercepts.rs` (12 entries + emit fns + collector module list)
- Modify: `crates/ailang-codegen/src/lib.rs:1071-1090` (intrinsic-storage flat-drop guard)

- [ ] **Step 1: Add `parse_raw_buf()` to the bijection collector's module list.**

Edit `crates/ailang-codegen/src/intercepts.rs`, `workspace_intrinsic_markers` (the `for module in [ parse_prelude(), parse_kernel_stub() ]` list, ~523). Add `ailang_surface::parse_raw_buf(),`. The raw-buf.3 type-scoped-poly arm + `scope_typedef_and_elems` then expand RawBuf's 4 ops over `{Int,Float,Bool}` into the 12 `RawBuf_op__T` markers automatically. (Until Step 2 adds the entries, this makes the bijection RED — Steps 1-2 land together.)

- [ ] **Step 2: Append the 12 `INTERCEPTS` entries.**

The mono symbols are `RawBuf_{new,get,set,size}__{Int,Float,Bool}` (raw-buf.3 scope-qualified mangling; the bijection test reports the exact strings if any differ). LLVM-type table — element `T` → store type / width / alloc-element-bytes:

| T | llvm elem type | width (bytes) |
|---|---|---|
| Int | `i64` | 8 |
| Float | `double` | 8 |
| Bool | `i1` | 1 |

`own (con RawBuf T)` and `borrow (con RawBuf T)` both lower to `ptr`. Entry sigs per op:

| op | expected_params | expected_ret |
|---|---|---|
| `RawBuf_new__T` | `["i64"]` (capacity n) | `"ptr"` |
| `RawBuf_get__T` | `["ptr","i64"]` (buf, i) | elem type (`i64`/`double`/`i1`) |
| `RawBuf_set__T` | `["ptr","i64", elem]` (buf, i, v) | `"ptr"` |
| `RawBuf_size__T` | `["ptr"]` (buf) | `"i64"` |

Add 12 `Intercept { name, expected_params, expected_ret, wants_alwaysinline: false, emit }` rows. (Verify each `expected_*` against what `llvm_type` delivers at the dispatch — the `eq__Unit` entry documents a past sig-mismatch from exactly this; confirm `llvm_type(Bool)` = `"i1"` per `synth.rs:18`.)

- [ ] **Step 3: Write the emit fns (Int variants in full; Float/Bool by the substitution table).**

Mirror `emit_eq_str` (`intercepts.rs:226`) for the Emitter API: param SSAs via `emitter.locals[n-k].1`, `emitter.fresh_ssa()`, `emitter.body.push_str(format!(…))`, terminal `ret` + `}\n\n` + `emitter.block_terminated = true`. Confirm the exact `@ailang_rc_alloc` call signature against an existing ADT-allocation call site (it returns the payload `ptr` with the rc-header auto-prepended). Slab layout: `[ size:i64 @ off 0 ][ elem_0 @ off 8 ][ elem_1 @ off 8+width ]…`.

`RawBuf_new__Int` (capacity `n` is the one param):
```rust
pub(crate) fn emit_rawbuf_new_int(emitter: &mut Emitter<'_>) -> Result<()> {
    let n = emitter.locals.len();
    let cap = emitter.locals[n - 1].1.clone();          // i64 capacity
    let elems_bytes = emitter.fresh_ssa();
    let total = emitter.fresh_ssa();
    let slab = emitter.fresh_ssa();
    // 8 (header) + cap * 8 (Int elements)
    emitter.body.push_str(&format!("  {elems_bytes} = mul i64 {cap}, 8\n"));
    emitter.body.push_str(&format!("  {total} = add i64 {elems_bytes}, 8\n"));
    emitter.body.push_str(&format!("  {slab} = call ptr @ailang_rc_alloc(i64 {total})\n"));
    emitter.body.push_str(&format!("  store i64 {cap}, ptr {slab}\n"));   // size header at off 0
    emitter.body.push_str(&format!("  ret ptr {slab}\n"));
    emitter.body.push_str("}\n\n");
    emitter.block_terminated = true;
    Ok(())
}
```

`RawBuf_get__Int` (buf `b`, index `i`):
```rust
pub(crate) fn emit_rawbuf_get_int(emitter: &mut Emitter<'_>) -> Result<()> {
    let n = emitter.locals.len();
    let b = emitter.locals[n - 2].1.clone();
    let i = emitter.locals[n - 1].1.clone();
    let off = emitter.fresh_ssa();
    let byteoff = emitter.fresh_ssa();
    let ptr = emitter.fresh_ssa();
    let v = emitter.fresh_ssa();
    emitter.body.push_str(&format!("  {off} = mul i64 {i}, 8\n"));         // i * width
    emitter.body.push_str(&format!("  {byteoff} = add i64 {off}, 8\n"));   // + header
    emitter.body.push_str(&format!("  {ptr} = getelementptr inbounds i8, ptr {b}, i64 {byteoff}\n"));
    emitter.body.push_str(&format!("  {v} = load i64, ptr {ptr}\n"));
    emitter.body.push_str(&format!("  ret i64 {v}\n"));
    emitter.body.push_str("}\n\n");
    emitter.block_terminated = true;
    Ok(())
}
```

`RawBuf_set__Int` (buf `b`, index `i`, value `v`; linear — returns `b`):
```rust
pub(crate) fn emit_rawbuf_set_int(emitter: &mut Emitter<'_>) -> Result<()> {
    let n = emitter.locals.len();
    let b = emitter.locals[n - 3].1.clone();
    let i = emitter.locals[n - 2].1.clone();
    let v = emitter.locals[n - 1].1.clone();
    let off = emitter.fresh_ssa();
    let byteoff = emitter.fresh_ssa();
    let ptr = emitter.fresh_ssa();
    emitter.body.push_str(&format!("  {off} = mul i64 {i}, 8\n"));
    emitter.body.push_str(&format!("  {byteoff} = add i64 {off}, 8\n"));
    emitter.body.push_str(&format!("  {ptr} = getelementptr inbounds i8, ptr {b}, i64 {byteoff}\n"));
    emitter.body.push_str(&format!("  store i64 {v}, ptr {ptr}\n"));
    emitter.body.push_str(&format!("  ret ptr {b}\n"));
    emitter.body.push_str("}\n\n");
    emitter.block_terminated = true;
    Ok(())
}
```

`RawBuf_size__Int` (buf `b`):
```rust
pub(crate) fn emit_rawbuf_size_int(emitter: &mut Emitter<'_>) -> Result<()> {
    let n = emitter.locals.len();
    let b = emitter.locals[n - 1].1.clone();
    let sz = emitter.fresh_ssa();
    emitter.body.push_str(&format!("  {sz} = load i64, ptr {b}\n"));
    emitter.body.push_str(&format!("  ret i64 {sz}\n"));
    emitter.body.push_str("}\n\n");
    emitter.block_terminated = true;
    Ok(())
}
```

**Float variants** (`emit_rawbuf_{new,get,set,size}_float`): identical to the Int variants except the element load/store type is `double` and `get`/`set` return/take `double`; element width stays **8** (so `new`'s `mul i64 {cap}, 8` and `get`/`set`'s `mul i64 {i}, 8` are unchanged). `get` ends `load double` + `ret double`; `set` does `store double {v}`. `new`/`size` are byte-identical to Int (header is always i64). 

**Bool variants** (`emit_rawbuf_{new,get,set,size}_bool`): element type `i1`, width **1**. `new`: `mul i64 {cap}, 1` (or just `add i64 {cap}, 8` — element bytes = cap*1). `get`/`set`: `mul i64 {i}, 1` for the element offset, then `load i1` / `store i1 {v}`. `get` ret `i1`; `set` ret `ptr`; `size` byte-identical to Int. (Verify-first: the `store i1 %v, ptr %p` / `load i1, ptr %p` syntax is valid LLVM — i1 occupies one byte in memory; `raw_buf_bool_e2e` is the catch.)

- [ ] **Step 4: Add the intrinsic-storage flat-drop guard.**

Edit `crates/ailang-codegen/src/lib.rs`, the drop-dispatch loop (`for def in &self.module.defs { if let Def::Type(td) = def { … } }`, ~1071). Before the `td.drop_iterative` split, add a guard: if `td` is intrinsic-storage — its module declares an `(intrinsic)`-bodied `new` op that constructs `td` (i.e. a `Def::Fn` named `new`, body `Term::Intrinsic`, whose return type mentions `(con <td.name> …)`) — emit a flat drop and `continue` past the generic ADT drop:

```rust
                    // raw-buf.4: a TypeDef whose construction is
                    // compiler-supplied (its `new` op is an (intrinsic),
                    // not a real term-ctor body) has a flat slab layout
                    // [size:i64][elements], NOT a tagged-ADT layout.
                    // The generic drop loads a tag at offset 0 and
                    // switches on it — but offset 0 here is the size,
                    // so the generic drop is wrong. Emit a flat drop: a
                    // single rc-dec on the slab pointer (primitive
                    // elements carry no recursive drops). Distinguishes
                    // RawBuf (intrinsic new) from StubT (real-body new →
                    // generic ADT drop).
                    if self.module.defs.iter().any(|d| matches!(d,
                        Def::Fn(f) if f.name == "new"
                            && matches!(f.body, Term::Intrinsic)
                            && fn_returns_type(f, &td.name)))
                    {
                        self.emit_flat_intrinsic_drop_fn(td);
                        continue;
                    }
```

Add `fn_returns_type` (walk the fn's return type for a `Type::Con { name == td_name }`, peeling `Forall`/`own`/`borrow` via `ParamMode` on `Type::Fn`) and `emit_flat_intrinsic_drop_fn` (mirror the generic drop's `join:` tail at `drop.rs:153-159`):

```rust
fn emit_flat_intrinsic_drop_fn(&mut self, td: &TypeDef) {
    let sym = format!("drop_{}_{}", self.module.name, td.name);
    self.body.push_str(&format!("define void @{sym}(ptr %p) {{\n"));
    self.body.push_str("  %isnull = icmp eq ptr %p, null\n");
    self.body.push_str("  br i1 %isnull, label %done, label %dec\n");
    self.body.push_str("dec:\n");
    self.body.push_str("  call void @ailang_rc_dec(ptr %p)\n");
    self.body.push_str("  br label %done\n");
    self.body.push_str("done:\n");
    self.body.push_str("  ret void\n");
    self.body.push_str("}\n\n");
}
```

(Confirm the exact drop-fn symbol naming `drop_<m>_<T>`, the null-guard/SSA conventions, and the `@ailang_rc_dec` call form against `emit_drop_fn_for_type` in `drop.rs:77-161` before writing — match its conventions exactly so the call sites that reference `drop_raw_buf_RawBuf` resolve. Also confirm whether a `partial_drop` helper is likewise expected for this type; if the dispatch loop unconditionally also emits `emit_partial_drop_fn_for_type`, decide whether the flat type needs one — mirror what the generic path guarantees its callers.)

- [ ] **Step 5: Build + bijection + a manual IR check.**

Run: `cargo build --workspace 2>&1 | tail -8`
Expected: build succeeds.

Run: `cargo test -p ailang-codegen intercepts_bijection_with_intrinsic_markers 2>&1 | grep -E "test result|FAILED"`
Expected: PASS — the 4 RawBuf markers expand to the 12 `RawBuf_op__T` entries, all matched (1 op → 3 entries × 4 ops = 12).

Run: `cargo test --workspace 2>&1 | grep -E "^test result:" | awk -F"[: ;]+" '{p+=$4; f+=$6; i+=$8} END{print "passed:",p," failed:",f," ignored:",i}'`
Expected: `passed: 672  failed: 0  ignored: 2` — no new test yet (entries + drop are exercised by Task 4's E2E); existing suite unaffected (no consumer instantiates RawBuf ops yet, so the emits/drop are not yet codegen'd; bijection green).

---

### Task 4: RawBuf E2E + drop leak test

**Files:**
- Create: `examples/raw_buf_int.ail`, `examples/raw_buf_float.ail`, `examples/raw_buf_bool.ail`, `examples/raw_buf_reject_str.ail`
- Test: `crates/ail/tests/e2e.rs` (append 5 tests)

- [ ] **Step 1: Create `examples/raw_buf_int.ail`** (the worked program, prints 60):

```text
(module raw_buf_int
  (fn main
    (type (fn-type (params) (ret (con Int))))
    (params)
    (body
      (let buf (new RawBuf (con Int) 3)
        (let buf (app RawBuf.set buf 0 10)
          (let buf (app RawBuf.set buf 1 20)
            (let buf (app RawBuf.set buf 2 30)
              (app + (app RawBuf.get buf 0)
                (app + (app RawBuf.get buf 1)
                  (app RawBuf.get buf 2))))))))))
```

(`text`-fenced: references the injected `raw_buf` module, so not gate-checkable standalone against the pre-iteration tree; the E2E in Step 5 is the ratifier. Confirm `main`'s expected printed value — the harness for an `Int`-returning main; mirror how `answer_intrinsic_builds_and_runs_printing_42` asserts `42`.)

- [ ] **Step 2: Create `examples/raw_buf_float.ail`** — a Float variant storing e.g. `1.5`, `2.5` and summing to a known Float; and **`examples/raw_buf_bool.ail`** — a Bool variant setting/getting a Bool and returning an Int discriminated on it (so `main : () -> Int` prints a known value, exercising the `i1` store/load + width-1 offsets). (Confirm the Float-print + Bool-branch shapes against existing float / bool E2E fixtures.)

- [ ] **Step 3: Create `examples/raw_buf_reject_str.ail`** (must-fail at check):

```text
(module raw_buf_reject_str
  (fn cant_str
    (type (fn-type (params (borrow (con RawBuf (con Str)))) (ret (con Str))))
    (params buf)
    (body (app RawBuf.get buf 0))))
```

- [ ] **Step 4: Append the E2E tests to `crates/ail/tests/e2e.rs`.**

Mirror `answer_intrinsic_builds_and_runs_printing_42` + its `build_and_run` harness for the run cases, and the param-in reject test shape for the check-fail case:

- `raw_buf_int_e2e` — `build_and_run("raw_buf_int.ail")` → stdout `60`.
- `raw_buf_float_e2e` — Float variant → its known value.
- `raw_buf_bool_e2e` — Bool variant → its known value.
- `raw_buf_param_in_reject_e2e` — `ail check examples/raw_buf_reject_str.ail` exits non-zero, stderr contains `param-not-in-restricted-set`.
- `raw_buf_no_leak` — `build_and_run_with_rc_stats("raw_buf_int.ail")` (`e2e.rs:2154`), assert the RC live-count is 0 at exit (the slab is dropped via the flat intrinsic drop). (Confirm the rc-stats harness's exact assertion shape.)

- [ ] **Step 5: Run the RawBuf E2E + full suite.**

Run: `cargo test -p ail raw_buf 2>&1 | grep -E "test result|FAILED"`
Expected: all five PASS — `raw_buf_int` prints `60`; Float/Bool variants print their known values; the Str fixture is rejected at check with `param-not-in-restricted-set`; the leak check shows 0 live.

Run: `cargo test --workspace 2>&1 | grep -E "^test result:" | awk -F"[: ;]+" '{p+=$4; f+=$6; i+=$8} END{print "passed:",p," failed:",f," ignored:",i}'`
Expected: `passed: 677  failed: 0  ignored: 2` — 672 + 5 new E2E (`raw_buf_int_e2e`, `raw_buf_float_e2e`, `raw_buf_bool_e2e`, `raw_buf_param_in_reject_e2e`, `raw_buf_no_leak`). The `.ll` snapshot tests stay green (no snapshot fixture uses RawBuf).

---

## Self-review

1. **Spec coverage.**
   - § Architecture pt 4 (raw_buf submodule + ops): Task 1.
   - § Architecture pt 4 (12 scope-qualified entries + emit): Task 3.
   - § Architecture pt 4 (Term::New desugar + remove both arms): Task 2.
   - § Architecture pt 4 (drop): Task 3 Step 4.
   - § Architecture pt 4 (ailang-surface wiring, count 4→5): Task 1 Steps 4-8.
   - § Concrete (raw_buf module / worked program / reject fixture / INTERCEPTS shape / desugar / slab): Tasks 1/4/3/2.
   - § Data-flow (build-time + codegen-time): Tasks 1-3.
   - § Testing raw-buf.4 bullets (round-trip, int/float/bool E2E, reject, drop leak, bijection, count): Tasks 1/3/4.

2. **Placeholder scan.** No "TBD/TODO/implement later". The Float/Bool emit variants are given as an exact substitution of the in-full Int emits (element type + width table), not "similar to" — every one of the 12 is fully determined. "Mirror <named site>" instructions (parse_raw_buf, the E2E harness, the round-trip test) name the authoritative verbatim source with the exact substitution.

3. **Type consistency.** Symbols: `RAW_BUF_AIL`, `parse_raw_buf`, `raw_buf` (module), `RawBuf` (type), `RawBuf_{new,get,set,size}__{Int,Float,Bool}` (12 entries == mono-minted == bijection-collected), `emit_rawbuf_*` (12 fns), `drop_raw_buf_RawBuf`, `@ailang_rc_alloc`, `@ailang_rc_dec`. Consistent across tasks.

4. **Step granularity.** Each step is one file create/edit or one command. Task 3 is the largest (12 emits + drop), but the emits are one mechanical family and the drop is one guard + two helpers.

5. **No commit steps.** None.

6. **Pin/replacement substring contiguity.** Asserted substrings: `param-not-in-restricted-set` (runtime stderr, not a plan-shipped body), `60` (program output), the workspace counts (`5`, in the verbatim replacement assertions — contiguous). The bijection symbol strings are produced at runtime by `mono_symbol_n`, not a shipped body. No soft-wrap split.

7. **Compile-gate vs. deferred-caller ordering.** Task 2 removes two codegen match arms — exhaustiveness is preserved (desugar eliminates Term::New before codegen; the `unreachable!` fallback is named if the compiler still demands an arm). Task 3's 12 entries + collector-list change land together (the bijection is RED between Step 1 and Step 2, both in Task 3, green by Step 5). No signature change defers a caller past a build gate; each task ends green.

8. **Verification-command filter strings.** `raw_buf_module_round_trips`, `intercepts_bijection_with_intrinsic_markers`, `new_stubt_builds_and_runs`, `raw_buf` (matches the 5 new E2E) — all name tests this plan creates or that recon confirmed exist. The per-task full-suite gates use the unfiltered suite + an explicit count assertion (awk), so "0 ran" cannot pass as success.

9. **Parse-the-bytes gate.** The surface-language bodies inlined (`raw_buf/source.ail`, the four `examples/raw_buf_*.ail` fixtures, the worked program) all reference the `raw_buf` kernel-tier module, which is reserved + only injected by this iteration's own Task 1 — so `ail check` cannot validate them standalone against the pre-iteration tree (`reserved-module-name` for the module source; `RawBuf` unresolved for the consumers). Gate N/A; they are ratified by the round-trip test (module) and the E2E (consumers) after Task 1/4 land. The raw_buf module Form-A was nonetheless gate-verified earlier this milestone (`ail check` → `ok` under the injected workspace). All other inlined bodies are Rust — caught by the `implement` compile gate.
