# Iteration ct.4: Milestone Close — Implementation Plan

> **Parent spec:** `docs/specs/0007-canonical-type-names.md`
>
> **For agentic workers:** REQUIRED SUB-SKILL: use `skills/implement`
> to run this plan. Steps use `- [ ]` checkboxes for tracking.

**Goal:** Land the milestone-closing consolidation: amend DESIGN.md
with the canonical-form rule, pin hashes for the two migrated
cross-module fixtures, add qualifier-trim-on-print to the prose
printer with a snapshot test, and recreate
`examples/compare_primitives_smoke.ail.json` as the end-to-end
demonstration that closes the iter-23.3-Task-4 bug.

**Architecture:** Four tasks across DESIGN, hash regression, prose
printer, and end-to-end fixture. Task 1 is design writing. Task 2
adds new hash-pin tests (the existing pins on `sum`/`list` are
intra-module and unaffected; the migrated `ordering_match` /
`test_22b1_dup_a` get new pins to lock the post-migration state).
Task 3 threads `module_name` context through the prose printer so
intra-module qualified Type::Cons get trimmed on print, plus a
snapshot for `ordering_match`. Task 4 authors the
`compare_primitives_smoke` fixture (9 Ord.compare invocations
across Int/Bool/Str, expected stdout `1\n2\n3\n1\n2\n3\n1\n2\n3\n`)
and adds an E2E test plus an IR-shape integration test asserting
the compare__T mono symbols are emitted.

**Tech Stack:** `docs/DESIGN.md`, `crates/ailang-core/src/hash.rs`,
`crates/ailang-prose/src/lib.rs`, `crates/ailang-prose/tests/snapshot.rs`,
`examples/*.ail.json` + `.prose.txt`, `crates/ail/tests/e2e.rs`.

---

## Files this plan creates or modifies

- Modify: `docs/DESIGN.md` — amend Decision 2 (around line 1067)
  with the canonical-form rule for `Type::Con` names; review the
  surrounding hash-stability promises at lines 1121, 1136-1139 to
  make sure they explicitly cite the migrated fixtures as the
  named exception.
- Modify: `crates/ailang-core/src/hash.rs` — append three new pin
  tests near the existing `iter22b1_schema_extension_preserves_pre_22b_hashes`
  block: one pinning the new canonical hashes of the two migrated
  fixtures, one asserting `sum.ail.json` and `list.ail.json` (both
  intra-module-only) still hash bit-identically.
- Modify: `crates/ailang-prose/src/lib.rs` — thread an
  `owning_module: &str` context through `write_module` → `write_def`
  → ... → `write_type`; in `write_type`'s `Type::Con` arm, trim a
  qualifier whose owner matches `owning_module`.
- Modify: `crates/ailang-prose/tests/snapshot.rs` — add one test
  `snapshot_ordering_match` consuming the new
  `examples/ordering_match.prose.txt` snapshot.
- Create: `examples/ordering_match.prose.txt` — committed prose
  snapshot for the migrated cross-module fixture.
- Create: `examples/compare_primitives_smoke.ail.json` — the
  iter-23.3 demonstration fixture.
- Modify: `crates/ail/tests/e2e.rs` — append two tests:
  `compare_primitives_smoke_prints_1_2_3_thrice` (E2E) and
  `compare_primitives_smoke_emits_compare_mono_symbols` (IR shape).

No files are deleted.

---

## Task 1: DESIGN.md Decision 2 amendment

Decision 2 (content-addressed defs) in DESIGN.md is the spec of
the `.ail.json` canonical form. It currently does not pin down
how `Type::Con` names are scoped — that policy lived in
JOURNAL-level prose until ct.1 made it normative. This task
writes the rule into DESIGN.md so future iters check against it
during architect drift review.

**Files:**
- Modify: `docs/DESIGN.md` near line 1067 (Decision 2 / canonical
  form) — add a new subsection or paragraph naming the rule.
- Modify: `docs/DESIGN.md` line 1136-1139 — update the
  `iter19b_*` regression-pin citation to also name the new
  ct.1-era pins for migrated fixtures.

- [ ] **Step 1: Read the Decision 2 surrounding context**

Read `docs/DESIGN.md` lines 1050-1145 (approximately). Identify
the natural insertion point for the canonical-form rule — likely
adjacent to the existing "JSON canonical hash for every existing
fixture stays bit-identical" paragraph at 1067-1070.

- [ ] **Step 2: Insert the canonical-form rule**

Edit `docs/DESIGN.md`. After the paragraph at lines 1067-1070
("JSON canonical hash for every existing fixture stays bit-
identical..."), insert a new paragraph block:

```markdown
**Type::Con name scoping (canonical form, since ct.1).** Within a
`.ail.json`, a `Type::Con.name` is interpreted relative to the
file's top-level `"name"` field (the owning module). Bare names
(no `.`) refer to a TypeDef in the owning module's own `defs`.
Cross-module references MUST be qualified `<owning_module>.<TypeName>`
where `<owning_module>` is a known module in the workspace.
Primitives (`Int`, `Bool`, `Str`, `Unit`, `Float`) are bare and
have no module qualifier. Bare cross-module references are a
schema violation (`WorkspaceLoadError::BareCrossModuleTypeRef`);
qualified references whose owner is unknown are also a violation
(`WorkspaceLoadError::BadCrossModuleTypeRef`). The same rule
applies to `Term::Ctor.type_name`.

Class names (`ClassDef.name`, `InstanceDef.class`,
`SuperclassRef.class`, `Constraint.class`) are NOT module-scoped
under this rule; they remain workspace-flat with
`MethodNameCollision` enforced at load. Class-name scoping is a
future milestone with its own DESIGN amendment.
```

- [ ] **Step 3: Update the regression-pin citation at 1136-1139**

Edit `docs/DESIGN.md`. Find the paragraph at lines 1136-1139 that
ends with "regression-pinned by `iter19b_empty_suppress_preserves_pre_19b_hashes`
and `iter19b_schema_extension_preserves_pre_19b_hashes`."

Append at the end of that paragraph:

```
The canonical-form tightening in ct.1 shifted the hashes of two
cross-module fixtures (`ordering_match.ail.json` and
`test_22b1_dup_a.ail.json`); all intra-module fixtures, including
the regression-pinned `sum.ail.json` and `list.ail.json`, remain
bit-identical. The new pins are
`ct4_migrated_fixtures_have_canonical_form_hashes` (locks the
post-migration hashes) and
`ct4_unmigrated_fixtures_remain_bit_identical` (re-asserts the
existing 13a/19b/22b.1 hashes still hold).
```

- [ ] **Step 4: Verify DESIGN.md still parses cleanly**

Run: `cargo doc --workspace --no-deps 2>&1 | grep -i 'DESIGN\.md\|warning' | head`

Expected: no new errors (DESIGN.md is rustdoc-rendered in places;
the additions are plain markdown with no special syntax).

- [ ] **Step 5: Commit**

```bash
git add docs/DESIGN.md
git commit -m "iter ct.4.1: DESIGN.md Decision 2 — canonical Type::Con name scoping rule"
```

---

## Task 2: Hash pins for migrated fixtures

The existing pin tests in `crates/ailang-core/src/hash.rs` use
`sum.ail.json` and `list.ail.json` — both intra-module, neither
touched by the ct.1 migration. Their pinned hashes remain valid
and don't need re-baselining. This task ADDS new pins that lock
in the canonical-form hashes of the two migrated fixtures, plus
re-asserts the unmigrated pins still hold.

**Files:**
- Modify: `crates/ailang-core/src/hash.rs` — append two new tests
  at the end of `mod tests`.

- [ ] **Step 1: Capture the current hashes of the migrated fixtures**

Run the following one-liner to print the canonical hash of each
migrated fixture's relevant def. From a Rust REPL is overkill;
write a single throwaway test in `crates/ailang-core/src/hash.rs`
that asserts known-wrong hashes (so it fails and prints the
actual hash):

Add inside `mod tests`:

```rust
    #[test]
    #[ignore]  // helper: run manually with --ignored
    fn print_migrated_fixture_hashes() {
        let manifest_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        let examples = manifest_dir.join("../../examples");

        let ord_src = std::fs::read(examples.join("ordering_match.ail.json")).unwrap();
        let ord_mod: crate::ast::Module = serde_json::from_slice(&ord_src).unwrap();
        let main_def = ord_mod.defs.iter().find(|d| d.name() == "main").unwrap();
        eprintln!("ordering_match::main: {}", def_hash(main_def));

        let dup_a_src = std::fs::read(examples.join("test_22b1_dup_a.ail.json")).unwrap();
        let dup_a_mod: crate::ast::Module = serde_json::from_slice(&dup_a_src).unwrap();
        for d in &dup_a_mod.defs {
            eprintln!("test_22b1_dup_a::{}: {}", d.name(), def_hash(d));
        }

        panic!("captured hashes — see stderr");
    }
```

Run: `cargo test --workspace -p ailang-core print_migrated_fixture_hashes --ignored -- --nocapture 2>&1 | grep '::'`

Expected: prints hash lines for `ordering_match::main` and each
`test_22b1_dup_a::<def_name>`. Record the hashes for use in Step 2.

- [ ] **Step 2: Replace the helper with the real pin test**

Edit `crates/ailang-core/src/hash.rs` — replace the throwaway
helper test with the real pin:

```rust
    /// Iter ct.4 (canonical-type-names milestone close): pin the
    /// canonical-form hashes of the two cross-module fixtures
    /// migrated by `ail migrate-canonical-types` in ct.1. These
    /// hashes are the post-migration state; pre-migration values
    /// (when both fixtures carried bare cross-module Type::Con)
    /// are no longer reproducible because the ct.1 validator
    /// rejects that shape upstream.
    #[test]
    fn ct4_migrated_fixtures_have_canonical_form_hashes() {
        let manifest_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        let examples = manifest_dir.join("../../examples");

        let ord_src = std::fs::read(examples.join("ordering_match.ail.json"))
            .expect("examples/ordering_match.ail.json present");
        let ord_mod: crate::ast::Module = serde_json::from_slice(&ord_src).unwrap();
        let main_def = ord_mod.defs.iter().find(|d| d.name() == "main").unwrap();
        assert_eq!(
            def_hash(main_def),
            // Replace this string with the actual hash printed in Step 1.
            "REPLACE_WITH_CAPTURED_HASH_FROM_STEP_1",
            "ordering_match::main canonical hash must match captured post-migration value"
        );

        let dup_a_src = std::fs::read(examples.join("test_22b1_dup_a.ail.json"))
            .expect("examples/test_22b1_dup_a.ail.json present");
        let dup_a_mod: crate::ast::Module = serde_json::from_slice(&dup_a_src).unwrap();
        // Pin the first def's hash. If test_22b1_dup_a has multiple defs,
        // pin only the type def that carries the migrated qualifier.
        let first_def = dup_a_mod.defs.first().expect("at least one def");
        assert_eq!(
            def_hash(first_def),
            "REPLACE_WITH_SECOND_CAPTURED_HASH_FROM_STEP_1",
            "test_22b1_dup_a::{} canonical hash must match captured post-migration value",
            first_def.name(),
        );
    }
```

You'll need to substitute the actual hash strings from Step 1's
captured output and remove the placeholder strings. If
`test_22b1_dup_a` has multiple defs of relevance, pin each (one
`assert_eq!` per def).

- [ ] **Step 3: Add a re-assertion pin for unmigrated fixtures**

Edit `crates/ailang-core/src/hash.rs` — append a second new test:

```rust
    /// Iter ct.4: re-assert that the canonical-form tightening
    /// did NOT change hashes of intra-module-only fixtures. The
    /// existing iter-13a / iter-19b / iter-22b.1 pin tests already
    /// assert these; this one names the canonical-type-names
    /// milestone explicitly so future archaeology finds the
    /// connection.
    #[test]
    fn ct4_unmigrated_fixtures_remain_bit_identical() {
        let manifest_dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        let examples = manifest_dir.join("../../examples");

        let sum_src = std::fs::read(examples.join("sum.ail.json")).unwrap();
        let sum_mod: crate::ast::Module = serde_json::from_slice(&sum_src).unwrap();
        let sum_def = sum_mod.defs.iter().find(|d| d.name() == "sum").unwrap();
        assert_eq!(def_hash(sum_def), "db33f57cb329935e",
            "sum.sum hash drifted across canonical-form tightening — unexpected");

        let list_src = std::fs::read(examples.join("list.ail.json")).unwrap();
        let list_mod: crate::ast::Module = serde_json::from_slice(&list_src).unwrap();
        let int_list_def = list_mod.defs.iter().find(|d| d.name() == "IntList").unwrap();
        assert_eq!(def_hash(int_list_def), "b082192bd0c99202",
            "list.IntList hash drifted across canonical-form tightening — unexpected");
    }
```

- [ ] **Step 4: Run the pin tests**

Run: `cargo test --workspace -p ailang-core ct4_migrated_fixtures_have_canonical_form_hashes ct4_unmigrated_fixtures_remain_bit_identical`

Expected: BOTH PASS.

- [ ] **Step 5: Run the full test suite**

Run: `cargo test --workspace`

Expected: all pass (test count grows by 2).

- [ ] **Step 6: Commit**

```bash
git add crates/ailang-core/src/hash.rs
git commit -m "iter ct.4.2: pin canonical-form hashes for migrated fixtures + unmigrated sanity"
```

---

## Task 3: Prose qualifier-trim-on-print + snapshot

The prose printer at `crates/ailang-prose/src/lib.rs:462` writes
`Type::Con.name` verbatim. When the canonical `.ail.json` already
has bare names for intra-module Type::Cons (the canonical
convention), this is fine. But the validator does not reject
qualified intra-module refs (it only rejects bare cross-module
and bad-qualified); a hand-authored fixture could legally have
`prelude.Ordering` inside prelude's own file. The prose form
should print this as bare `Ordering` so the prose surface stays
LLM-author-friendly (qualifier omitted because it follows from
the file's module name).

This task threads `owning_module` context through the prose
printer and trims at `write_type`'s `Type::Con` arm. Plus a
snapshot test that pins the print behaviour for the migrated
cross-module fixture (`ordering_match.ail.json`, which uses
`prelude.Ordering` cross-module qualifier — the trim does NOT
fire here because the qualifier's owner differs from the file's
module).

**Files:**
- Modify: `crates/ailang-prose/src/lib.rs` — thread `owning_module`
  through every `write_*` fn signature from `write_module` down to
  `write_type`; trim in `write_type`'s `Type::Con` arm.
- Create: `examples/ordering_match.prose.txt` — committed
  snapshot.
- Modify: `crates/ailang-prose/tests/snapshot.rs` — register one
  new snapshot test.

- [ ] **Step 1: Write the RED test for trim behaviour**

Append to `crates/ailang-prose/src/lib.rs` `mod tests` (or wherever
the existing unit tests live — search for `mod tests` near the
bottom of the file):

```rust
    /// ct.4 Task 3: when a `Type::Con.name` is qualified with the
    /// owning module's own name (e.g. `prelude.Ordering` inside
    /// `prelude`'s own file), the prose printer must trim the
    /// qualifier and emit bare `Ordering`. Cross-module qualified
    /// refs (`prelude.Ordering` inside any non-prelude file)
    /// round-trip verbatim.
    #[test]
    fn type_con_qualifier_trimmed_when_owner_matches_module() {
        use ailang_core::ast::{Module, Def, FnDef, Type, Term, Literal, ParamMode};

        let m = Module {
            schema: "ailang/v0".into(),
            name: "prelude".into(),
            imports: vec![],
            defs: vec![Def::Fn(FnDef {
                name: "noop".into(),
                ty: Type::Fn {
                    params: vec![],
                    ret: Box::new(Type::Con {
                        name: "prelude.Ordering".into(),
                        args: vec![],
                    }),
                    effects: vec![],
                    param_modes: vec![],
                    ret_mode: ParamMode::Implicit,
                },
                params: vec![],
                body: Term::Ctor {
                    type_name: "prelude.Ordering".into(),
                    ctor: "EQ".into(),
                    args: vec![],
                },
                doc: None,
                suppress: vec![],
            })],
        };

        let prose = module_to_prose(&m);
        assert!(
            prose.contains("-> Ordering"),
            "expected bare `Ordering` in fn return type (owner == file's \
             module); got prose:\n{}",
            prose
        );
        assert!(
            !prose.contains("prelude.Ordering"),
            "expected NO `prelude.Ordering` after trim; got prose:\n{}",
            prose
        );
    }

    /// ct.4 Task 3: a cross-module Type::Con (owner != current
    /// file's module) must round-trip verbatim — no trim.
    #[test]
    fn type_con_qualifier_preserved_when_owner_differs() {
        use ailang_core::ast::{Module, Def, FnDef, Type, Term, Literal, ParamMode, Import};

        let m = Module {
            schema: "ailang/v0".into(),
            name: "user".into(),
            imports: vec![Import { module: "prelude".into(), alias: None }],
            defs: vec![Def::Fn(FnDef {
                name: "lt".into(),
                ty: Type::Fn {
                    params: vec![],
                    ret: Box::new(Type::Con {
                        name: "prelude.Ordering".into(),
                        args: vec![],
                    }),
                    effects: vec![],
                    param_modes: vec![],
                    ret_mode: ParamMode::Implicit,
                },
                params: vec![],
                body: Term::Ctor {
                    type_name: "prelude.Ordering".into(),
                    ctor: "LT".into(),
                    args: vec![],
                },
                doc: None,
                suppress: vec![],
            })],
        };

        let prose = module_to_prose(&m);
        assert!(
            prose.contains("prelude.Ordering"),
            "expected qualified `prelude.Ordering` preserved (owner != file's \
             module); got prose:\n{}",
            prose
        );
    }
```

- [ ] **Step 2: Run the RED tests to verify they fail**

Run: `cargo test --workspace -p ailang-prose type_con_qualifier_trimmed type_con_qualifier_preserved`

Expected:
- `type_con_qualifier_trimmed_when_owner_matches_module`: FAIL (current printer writes `prelude.Ordering` verbatim).
- `type_con_qualifier_preserved_when_owner_differs`: PASS (current printer already writes qualified verbatim).

- [ ] **Step 3: Thread `owning_module` through the print signatures**

Edit `crates/ailang-prose/src/lib.rs`. Modify the following
signatures to add `owning_module: &str` as the last parameter
(after `level: usize` where present, before `out`-mutating return
of `()`):

- `write_def`
- `write_type_def`
- `write_fn_def`
- `write_const_def`
- `write_class_def`
- `write_instance_def`
- `write_type`
- `write_mode_type` (if it exists; check)
- any other `write_*` that consumes a `Type` or `Term`

For each call site within the same file, add the propagated
`m.name.as_str()` argument from the entry point (`module_to_prose`
passes `m.name.as_str()` to `write_module`'s helper, which then
threads it to every `write_def` call).

Refactor the entry point `module_to_prose`:

```rust
pub fn module_to_prose(m: &Module) -> String {
    let mut out = String::new();
    write_module(&mut out, m);
    out
}
```

stays the same; the threading begins inside `write_module`.

`write_module`'s body — the `m.name.as_str()` is captured locally
(let `module_name = m.name.as_str();`) and passed to each
`write_def(&mut out, def, level, module_name)` call.

- [ ] **Step 4: Apply the trim in `write_type`'s `Type::Con` arm**

Edit `crates/ailang-prose/src/lib.rs` around line 465. The `Type::Con`
arm currently reads:

```rust
        Type::Con { name, args } => {
            out.push_str(name);
            // ... args writing
        }
```

Replace with:

```rust
        Type::Con { name, args } => {
            // Trim a qualifier whose owner matches the current
            // file's module: `prelude.Ordering` printed from
            // inside `prelude` becomes bare `Ordering`. Cross-
            // module qualifiers (`prelude.Ordering` printed from
            // inside any non-prelude module) survive verbatim.
            let display_name = match name.split_once('.') {
                Some((owner, suffix)) if owner == owning_module => suffix,
                _ => name.as_str(),
            };
            out.push_str(display_name);
            // ... args writing (preserved verbatim, recursing
            // into write_type with the same owning_module)
        }
```

Where the args recursion calls `write_type(out, a)`, update to
`write_type(out, a, owning_module)`.

- [ ] **Step 5: Apply the same trim in `Term::Ctor`'s type_name (in write_term, wherever it lives)**

The prose printer also writes `Term::Ctor.type_name` somewhere
in its term-lowering. Search for `Term::Ctor` in `crates/ailang-prose/src/lib.rs`
and find the analogous `out.push_str(type_name)` site. Apply the
same trim logic:

```rust
// in the Term::Ctor write arm — find the existing string-push site
let display_type = match type_name.split_once('.') {
    Some((owner, suffix)) if owner == owning_module => suffix,
    _ => type_name.as_str(),
};
out.push_str(display_type);
```

- [ ] **Step 6: Run the RED tests now expecting GREEN**

Run: `cargo test --workspace -p ailang-prose type_con_qualifier_trimmed type_con_qualifier_preserved`

Expected: BOTH PASS.

- [ ] **Step 7: Regenerate existing prose snapshots**

The trim changes how `prelude.Ordering` (and any other
qualifier-matching pattern) renders. Most existing prose
snapshots are intra-module-only fixtures with no qualified
Type::Cons — they should be byte-identical. Verify:

Run: `cargo test --workspace -p ailang-prose`

Expected: all existing snapshot tests still pass. If any fail
with a `.prose.txt.actual` byte diff, manually inspect the diff:
- If the diff is ONLY the qualifier-trim behaviour we just added
  (and the snapshot input file does have qualified intra-module
  Type::Cons), regenerate the snapshot:
  `cargo run -p ail -- prose examples/<stem>.ail.json > examples/<stem>.prose.txt`.
  Confirm the diff post-regenerate is what you expect.
- If the diff is OTHERWISE unexpected, that is a bug — investigate.

For each snapshot whose `.actual` file appeared, decide whether
to regenerate or revert.

- [ ] **Step 8: Create the `ordering_match` snapshot**

Run: `cargo run -p ail -- prose examples/ordering_match.ail.json > examples/ordering_match.prose.txt`

Expected: command succeeds, the output file is non-empty and
contains `prelude.Ordering` (cross-module qualifier preserved
because `prelude` ≠ `ordering_match`).

- [ ] **Step 9: Register the new snapshot test**

Edit `crates/ailang-prose/tests/snapshot.rs`. Append:

```rust
#[test]
fn snapshot_ordering_match() {
    check_snapshot("ordering_match");
}
```

- [ ] **Step 10: Run the prose test suite**

Run: `cargo test --workspace -p ailang-prose`

Expected: all pass, including the new `snapshot_ordering_match`.

- [ ] **Step 11: Run the full test suite**

Run: `cargo test --workspace`

Expected: all pass.

- [ ] **Step 12: Commit**

```bash
git add crates/ailang-prose/src/lib.rs \
        crates/ailang-prose/tests/snapshot.rs \
        examples/ordering_match.prose.txt
git commit -m "iter ct.4.3: prose qualifier-trim-on-print + ordering_match snapshot"
```

---

## Task 4: Recreate `compare_primitives_smoke.ail.json` + E2E

This task resumes the paused iter 23.3 work (TaskList #15+#16):
recreate the end-to-end fixture that demonstrates the
iter-23.1/23.3 bug closure, run it through the full pipeline,
and lock the IR-shape integration assertion.

The fixture: consumer module `compare_primitives_smoke` imports
prelude, calls `Ord.compare` on 9 pairs (3 each of Int/Bool/Str
arranged as LT-case / EQ-case / GT-case), pattern-matches each
result on `LT | EQ | GT`, prints 1 / 2 / 3 respectively. Expected
stdout: `1\n2\n3\n1\n2\n3\n1\n2\n3\n`.

**Files:**
- Create: `examples/compare_primitives_smoke.ail.json` — the
  fixture.
- Modify: `crates/ail/tests/e2e.rs` — append the E2E test and the
  IR-shape integration test.

- [ ] **Step 1: Author the canonical-form fixture**

Create `examples/compare_primitives_smoke.ail.json` with the
structure below. The fixture has one fn `main` with a `body`
that is a sequence of 9 `do io/print_int` statements; each
`print_int` wraps a `match` on `(call prelude.compare A B)`
returning a `prelude.Ordering`. Use qualified
`prelude.Ordering` throughout (canonical post-ct.1 since the
type's owner ≠ this file's module).

For brevity, build the fixture incrementally — start with one
case, verify it loads, then add the rest. The shape of a single
case (Int, LT):

```json
{
  "t": "do",
  "op": "io/print_int",
  "args": [
    {
      "t": "match",
      "scrutinee": {
        "t": "app",
        "fn": { "t": "var", "name": "prelude.compare" },
        "args": [
          { "t": "lit", "lit": { "kind": "int", "value": 1 } },
          { "t": "lit", "lit": { "kind": "int", "value": 2 } }
        ]
      },
      "arms": [
        {
          "pat": { "p": "ctor", "ctor": "LT", "fields": [] },
          "body": { "t": "lit", "lit": { "kind": "int", "value": 1 } }
        },
        {
          "pat": { "p": "ctor", "ctor": "EQ", "fields": [] },
          "body": { "t": "lit", "lit": { "kind": "int", "value": 2 } }
        },
        {
          "pat": { "p": "ctor", "ctor": "GT", "fields": [] },
          "body": { "t": "lit", "lit": { "kind": "int", "value": 3 } }
        }
      ]
    }
  ]
}
```

Compose 9 such blocks (Int LT/EQ/GT, Bool LT/EQ/GT, Str LT/EQ/GT)
in a `seq` chain. For Bool, use `bool` literals (`{"kind": "bool", "value": false}`);
for Str, use `str` literals (`{"kind": "str", "value": "a"}`).

The fn `main` returns `Unit` with `IO` effect:

```json
{
  "schema": "ailang/v0",
  "name": "compare_primitives_smoke",
  "imports": [{ "module": "prelude" }],
  "defs": [
    {
      "kind": "fn",
      "name": "main",
      "type": {
        "k": "fn",
        "params": [],
        "ret": { "k": "con", "name": "Unit" },
        "effects": ["IO"]
      },
      "params": [],
      "body": { "t": "seq", "lhs": <case 1>, "rhs": { "t": "seq", "lhs": <case 2>, "rhs": ... <case 9> ... } }
    }
  ]
}
```

The 9 cases pair-pattern (which value, which compare, expected output):

| # | type | A      | B      | expected match | print |
|---|------|--------|--------|----------------|-------|
| 1 | Int  | 1      | 2      | LT             | 1     |
| 2 | Int  | 1      | 1      | EQ             | 2     |
| 3 | Int  | 2      | 1      | GT             | 3     |
| 4 | Bool | false  | true   | LT             | 1     |
| 5 | Bool | false  | false  | EQ             | 2     |
| 6 | Bool | true   | false  | GT             | 3     |
| 7 | Str  | "a"    | "b"    | LT             | 1     |
| 8 | Str  | "a"    | "a"    | EQ             | 2     |
| 9 | Str  | "b"    | "a"    | GT             | 3     |

You'll write this manually as one big JSON file. Use 2-space
indentation and standard `serde_json`-canonical key ordering
(the validator + manifest test will fail otherwise; alternatively,
run the file through `cargo run -p ail -- manifest examples/compare_primitives_smoke.ail.json`
to canonicalise once it loads, then commit the canonicalised
form).

- [ ] **Step 2: Verify the fixture loads + typechecks**

Run: `cargo run -p ail -- check examples/compare_primitives_smoke.ail.json`

Expected: exit 0, no diagnostics. If validator complains about
canonical form (e.g. bare `Ordering` somewhere), fix and re-run.
If typechecker complains about an unknown ctor or pattern type
mismatch, that is the iter-23.1 bug — investigate (it should
NOT happen post-ct.2).

- [ ] **Step 3: Verify the fixture runs end-to-end**

Run: `cargo run -p ail -- run examples/compare_primitives_smoke.ail.json`

Expected: stdout exactly `1\n2\n3\n1\n2\n3\n1\n2\n3\n` (nine
lines, no extra newline at the very end depending on the runtime
printer convention — match whatever the existing
`ordering_match_via_prelude_prints_1` test asserts for trailing
newline).

If the run fails, the iter-23.1 bug closure is NOT complete —
escalate to orchestrator.

- [ ] **Step 4: Append the E2E test to e2e.rs**

Edit `crates/ail/tests/e2e.rs`. Append after the
`ordering_match_via_prelude_prints_1` test (around line 920):

```rust
/// Iter 23.3 Task 4 (resumed in ct.4): the end-to-end
/// demonstration that the iter-23.1 cross-module Type::Con
/// mismatch bug is closed. `examples/compare_primitives_smoke.ail.json`
/// imports prelude, calls `prelude.compare` on three pairs each
/// of Int / Bool / Str (arranged LT / EQ / GT per type), and
/// pattern-matches the result. Expected stdout encodes the
/// 9-case decision lattice as `1\n2\n3` × 3.
///
/// Pre-ct.1 / pre-ct.2, the bare `Ordering` returned by
/// `compare` mismatched the qualified `prelude.Ordering`
/// scrutinee at the user-side pattern lookup. Post-canonical-
/// type-names, the scrutinee is qualified throughout, the
/// pattern lookup is type-driven, and the run completes cleanly.
#[test]
fn compare_primitives_smoke_prints_1_2_3_thrice() {
    let stdout = build_and_run("compare_primitives_smoke.ail.json");
    assert_eq!(stdout, "1\n2\n3\n1\n2\n3\n1\n2\n3\n");
}
```

- [ ] **Step 5: Append the IR-shape integration test**

Append immediately after the E2E test:

```rust
/// Iter 23.3 Task 4 / IR-shape: the mono pass must emit
/// `compare__Int`, `compare__Bool`, and `compare__Str` symbols
/// driven by the three `prelude.compare` call sites in the
/// smoke fixture. Codegen's `try_emit_primitive_instance_body`
/// intercepts each one (iter 23.3.2). This test pins the
/// presence of those symbols in the emitted IR so a future
/// refactor cannot silently drop one.
#[test]
fn compare_primitives_smoke_emits_compare_mono_symbols() {
    let ir = emit_ir("compare_primitives_smoke.ail.json");
    assert!(
        ir.contains("compare__Int") || ir.contains("@compare__Int"),
        "compare__Int symbol missing from emitted IR"
    );
    assert!(
        ir.contains("compare__Bool") || ir.contains("@compare__Bool"),
        "compare__Bool symbol missing from emitted IR"
    );
    assert!(
        ir.contains("compare__Str") || ir.contains("@compare__Str"),
        "compare__Str symbol missing from emitted IR"
    );
}
```

If a helper `emit_ir(fixture: &str) -> String` does not already
exist in `e2e.rs`, add it adjacent to `build_and_run` (it should
invoke `cargo run -p ail -- emit-ir <fixture>` and capture
stdout). Use the existing `build_and_run`'s implementation as a
template.

- [ ] **Step 6: Run the new E2E + IR tests**

Run: `cargo test --workspace -p ail compare_primitives_smoke_prints compare_primitives_smoke_emits`

Expected: BOTH PASS.

- [ ] **Step 7: Run the full test suite**

Run: `cargo test --workspace`

Expected: all pass.

- [ ] **Step 8: Commit**

```bash
git add examples/compare_primitives_smoke.ail.json crates/ail/tests/e2e.rs
git commit -m "iter ct.4.4: compare_primitives_smoke E2E fixture + IR-shape test (closes iter 23.3 Task 4)"
```

---

## Closing checks

- [ ] **Step C1: Bench script smoke run**

Run: `bash bench/run.sh` (or whichever entry point the project
uses; consult `bench/README.md` or `skills/audit/SKILL.md`).

Expected: exit 0, or a ratified non-zero per the audit-skill
policy. No new regressions vs. baseline.

- [ ] **Step C2: Confirm all acceptance criteria from the spec**

Verify each item in `docs/specs/0007-canonical-type-names.md`
§ "Acceptance criteria":

1. ✅ `load_workspace` validates every `Type::Con` (ct.1).
2. ✅ Every fixture migrated to qualified form (ct.1).
3. ✅ Four obsolete mechanisms deleted (ct.2.2, ct.2.3, ct.3.1, ct.3.2).
4. ✅ `qualify_local_types` audited and applied uniformly (ct.2.1).
5. ✅ `cargo build --workspace && cargo test --workspace` green (this commit).
6. ✅ Iter 23.3 Task 4+5 resumed and complete (ct.4 Task 4 above).
7. ✅ DESIGN.md amended (ct.4 Task 1).
8. ✅ JOURNAL entry (ct.4 Task C3 below).
9. ⏳ Bench scripts exit 0 (verify via C1).

- [ ] **Step C3: JOURNAL entry**

Append to `docs/JOURNAL.md`:

```markdown
## 2026-05-11 — Iteration ct.4: canonical-type-names milestone close

Four tasks landed, closing the milestone:

- **ct.4.1**: amended DESIGN.md Decision 2 with the canonical
  Type::Con name scoping rule (bare = local, qualified =
  cross-module, primitives bare). Updated the regression-pin
  citation at the surrounding "hashes stay bit-identical"
  paragraph to name the two new ct.4 pins.
- **ct.4.2**: added two new pin tests in
  `crates/ailang-core/src/hash.rs` —
  `ct4_migrated_fixtures_have_canonical_form_hashes` (locks the
  post-migration hashes of `ordering_match.ail.json` and
  `test_22b1_dup_a.ail.json`) and
  `ct4_unmigrated_fixtures_remain_bit_identical` (re-asserts the
  unchanged `sum`/`list` hashes).
- **ct.4.3**: added qualifier-trim-on-print to the prose
  printer. `write_type` (and `Term::Ctor.type_name` writing)
  now trims a qualifier whose owner matches the current file's
  module. The `owning_module` context is threaded from
  `write_module` down through the call chain. Two unit tests
  pin the trim and the cross-module preserve behaviours; the
  `ordering_match.prose.txt` snapshot is committed.
- **ct.4.4**: recreated `examples/compare_primitives_smoke.ail.json`
  (the iter-23.3 Task 4 demonstration fixture). 9 cases across
  Int / Bool / Str, expected stdout `1\n2\n3` × 3. Two new
  E2E tests in `crates/ail/tests/e2e.rs` —
  `compare_primitives_smoke_prints_1_2_3_thrice` (output
  assertion) and `compare_primitives_smoke_emits_compare_mono_symbols`
  (IR-shape assertion that mono emits compare__Int /
  compare__Bool / compare__Str symbols).

The canonical-type-names milestone closes:
- The structural invariant: every `Type::Con` in canonical
  `.ail.json` is bare (= local) or qualified
  (`<owner>.<TypeName>`, with primitives bare).
- The four obsolete imports-fallback / overlay mechanisms named
  in the ct.1 catalogue are gone (Pattern::Ctor, Term::Ctor
  synth, codegen `lookup_ctor_by_type`, mono
  `apply_per_module_ctor_index_overlay`'s ctor_index half).
- The iter-23.1-Task-4 bug is empirically closed: the smoke
  fixture compiles, runs, and prints the expected 9-line output
  end-to-end without any further compiler changes.

Workspace at milestone close: full `cargo build --workspace` and
`cargo test --workspace` green, 453+ tests passing
(ct.4 adds 4 new tests: 2 pin + 2 prose + 2 E2E, minus or plus
any shifts in other test count).

The skill-system pipeline calls for `audit` next (drift review +
bench regression + rustdoc), then `fieldtest` (real-world `.ailx`
examples authored against DESIGN.md only).

Out of scope, deferred:
- The codegen `lookup_ctor_in_pattern` helper (imports-walk, but
  no scrutinee type to type-anchor; a later iter can plumb Type
  through pattern lowering if desired).
- `check_in_workspace`'s analogous per-module overlay in
  `crates/ailang-check/src/lib.rs:1234` (its env.ctor_index half
  serves the duplicate-detection diagnostic at workspace-build
  time, not the runtime ctor lookup; not in the canonical-type-
  names scope).
- Class names (`ClassDef.name`, `InstanceDef.class`, etc.) are
  intentionally bare and workspace-flat post-ct.1; type-driven
  method dispatch is its own milestone (already named in
  `docs/roadmap.md` as a P2 item).
```

- [ ] **Step C4: Commit the JOURNAL entry**

```bash
git add docs/JOURNAL.md
git commit -m "journal: ct.4 canonical-type-names milestone close"
```

- [ ] **Step C5: Optional roadmap update**

If the user wants the milestone removed from
`docs/roadmap.md` (or marked done with a checkmark), make that
edit now and commit alongside the JOURNAL entry. Otherwise leave
the roadmap as-is — the orchestrator typically prunes finished
entries in a small follow-up commit.
