# pd.1 — core API split (load_modules_with + build_workspace) — Implementation Plan

> **Parent spec:** `docs/specs/2026-05-14-prelude-decouple.md`
>
> **For agentic workers:** REQUIRED SUB-SKILL: use `skills/implement`
> to run this plan. Steps use `- [ ]` checkboxes for tracking.

**Goal:** Introduce two new public fns in `crates/ailang-core/src/workspace.rs`
(`load_modules_with` + `build_workspace`), thread `implicit_imports: &[&str]`
through `validate_canonical_type_names`, and replace the hardcoded `"prelude"`
fallbacks in `check_class_ref` and `check_type_con_name` with the parameterised
walk. `load_workspace_with` survives pd.1 as a thin compatibility shim composed
of the new fns + the still-in-place prelude inject; pd.2 rewires surface to use
the new API directly and removes the shim.

**Architecture:** core's existing `load_workspace_with<F>` is the single block
that today does DFS + reserved-name + inject + 3-stage validation. pd.1 carves
out `load_modules_with` (DFS only) and `build_workspace` (validation +
registry) as new public fns; the surviving `load_workspace_with` becomes a
3-line composition `load_modules_with → reserved-name + inject → build_workspace`.
core's `src/` literal-`"prelude"` strings drop from 8 to 4 (the inject step's
two and `WorkspaceLoadError::ReservedModuleName`'s string-arg site stay
because the shim still holds them; the four diagnostic-fallback occurrences
on lines 1084 / 1086 / 1148 / 1150 are removed by the threading). Surface
and downstream tests are unchanged in pd.1.

**Tech Stack:** `ailang-core` (workspace.rs only). No surface, codegen, check,
or CLI changes.

---

**Files this plan creates or modifies:**

- Modify: `crates/ailang-core/src/workspace.rs:413-528` — extract DFS pre-amble
  into `load_modules_with` (lines 462-491), extract validation pipeline into
  `build_workspace` (lines 506-528), refit `load_workspace_with` as a 3-line
  shim. `load_prelude` (425-428) and `PRELUDE_JSON` (417-419) stay in pd.1
  (still consumed by the shim's inject step); they leave in pd.2.
- Modify: `crates/ailang-core/src/workspace.rs:925-1097` — add
  `implicit_imports: &[&str]` parameter to `validate_canonical_type_names`
  (signature at line 938-940); thread to `check_class_ref` (line 1041-1046)
  and `check_type_con_name` (line 1101-1106); replace literal-`"prelude"`
  fallback blocks at lines 1084-1091 and 1148-1155 with the iter form.
- Modify: `crates/ailang-core/src/workspace.rs:437-439` — retire `pub fn
  load_workspace`. Zero production callers; the rustdoc example at lines
  22-31 referencing it gets rewritten to use the shim.
- Modify: `crates/ailang-core/src/workspace.rs:1-32` — module rustdoc.
  Update the example block (lines 22-31) and the "single entry point"
  wording (line 8) to reflect the shim shape.
- Modify: `crates/ailang-core/src/workspace.rs` `#[cfg(test)] mod tests`
  block (1583-2749) — direct callers of `validate_canonical_type_names`
  add `&["prelude"]` as second arg (~12 tests). Direct callers of
  `load_workspace`, `load_workspace_with`, `build_registry` are
  unchanged (the shim + the unchanged validators preserve the public
  signature for the latter two; the legacy `load_workspace` wrapper has
  no in-tree test caller per recon).
- Test: `crates/ailang-core/src/workspace.rs` mod tests — three new
  `#[test]` fns to pin the new API: (a) `load_modules_with` returns
  modules WITHOUT the prelude (proves it is loader-only), (b)
  `build_workspace` accepts a pre-assembled modules-map and runs the
  three-stage validation, (c) the shim composition `load_workspace_with`
  produces an output byte-identical to today (regression pin against
  the refactor).

---

### Task 1: Add `pub fn load_modules_with` (DFS extraction)

**Files:**
- Modify: `crates/ailang-core/src/workspace.rs` — add new fn between current
  `load_workspace_with` and the prelude-related helpers (anywhere in lines
  430-530 is fine; suggest just above `load_workspace_with`).

- [ ] **Step 1: Write the failing test** in the `#[cfg(test)] mod tests`
  block at the end of `workspace.rs`.

```rust
#[test]
fn load_modules_with_returns_modules_without_prelude() {
    let dir = tempfile::tempdir().unwrap();
    write_module(dir.path(), "main", &[]);
    let entry = dir.path().join("main.ail.json");

    let (entry_name, root_dir, modules) =
        load_modules_with(&entry, load_one).expect("load");

    assert_eq!(entry_name, "main");
    assert_eq!(root_dir, dir.path().to_path_buf());
    assert!(
        !modules.contains_key("prelude"),
        "load_modules_with must not auto-inject prelude (that is build_workspace's caller's job)"
    );
    assert!(modules.contains_key("main"));
}
```

- [ ] **Step 2: Run test to verify it fails**

Run: `cargo test -p ailang-core load_modules_with_returns_modules_without_prelude`
Expected: FAIL with "cannot find function `load_modules_with` in this scope"

- [ ] **Step 3: Add the new fn**

Place this above `load_workspace_with` (anywhere in the 430-530 range works;
keep `PRELUDE_JSON` and `load_prelude` adjacent to `load_workspace_with` for
locality):

```rust
/// pd.1: extract the DFS pre-amble of `load_workspace_with` into a public
/// loader-only fn. Returns `(entry_name, root_dir, modules)` with NO prelude
/// injected and NO validation run. The caller is responsible for injecting
/// any implicit modules (e.g. prelude) and then handing the result to
/// `build_workspace` for validation + registry construction.
///
/// Surface composes this with a prelude-injection step in pd.2; pd.1 keeps
/// the shim `load_workspace_with` callable so surface is unchanged.
pub fn load_modules_with<F>(
    entry_path: &Path,
    loader: F,
) -> Result<(String, PathBuf, BTreeMap<String, Module>), WorkspaceLoadError>
where
    F: Fn(&Path) -> Result<Module, WorkspaceLoadError> + Copy,
{
    let entry_path = entry_path.to_path_buf();
    let root_dir = entry_path
        .parent()
        .map(Path::to_path_buf)
        .unwrap_or_else(|| PathBuf::from("."));

    let entry_module = loader(&entry_path)?;
    let expected_entry_name = module_name_from_path(&entry_path);
    if entry_module.name != expected_entry_name {
        return Err(WorkspaceLoadError::ModuleNameMismatch {
            name_in_file: entry_module.name.clone(),
            name_from_path: expected_entry_name,
        });
    }

    let entry_name = entry_module.name.clone();

    let mut modules: BTreeMap<String, Module> = BTreeMap::new();
    let mut visiting: Vec<String> = Vec::new();
    let mut visiting_set: HashSet<String> = HashSet::new();

    visit(
        entry_module,
        &root_dir,
        &mut modules,
        &mut visiting,
        &mut visiting_set,
        loader,
    )?;

    Ok((entry_name, root_dir, modules))
}
```

- [ ] **Step 4: Run test to verify it passes**

Run: `cargo test -p ailang-core load_modules_with_returns_modules_without_prelude`
Expected: PASS.

- [ ] **Step 5: Run full core test suite to verify no regression**

Run: `cargo test -p ailang-core`
Expected: all existing tests pass (the new fn is additive; nothing else
calls it yet).

---

### Task 2: Add `pub fn build_workspace` (validation pipeline extraction)

**Files:**
- Modify: `crates/ailang-core/src/workspace.rs` — add new fn next to
  `load_modules_with`. The `implicit_imports: &[&str]` parameter is
  declared on `build_workspace` AND threaded into the call to
  `validate_canonical_type_names` (which gets the parameter in Task 3).

- [ ] **Step 1: Write the failing test**

Place in the `#[cfg(test)] mod tests` block:

```rust
#[test]
fn build_workspace_accepts_assembled_modules_and_runs_validation() {
    let dir = tempfile::tempdir().unwrap();
    write_module(dir.path(), "main", &[]);
    let entry = dir.path().join("main.ail.json");

    let (entry_name, root_dir, mut modules) =
        load_modules_with(&entry, load_one).expect("load");

    // Caller-side prelude inject (mirrors what surface will do in pd.2).
    let prelude = load_prelude();
    modules.insert("prelude".to_string(), prelude);

    let ws = build_workspace(entry_name, root_dir, modules, &["prelude"])
        .expect("build");

    assert_eq!(ws.entry, "main");
    assert!(ws.modules.contains_key("main"));
    assert!(ws.modules.contains_key("prelude"));
}
```

- [ ] **Step 2: Run test to verify it fails**

Run: `cargo test -p ailang-core build_workspace_accepts_assembled_modules_and_runs_validation`
Expected: FAIL with "cannot find function `build_workspace` in this scope".

- [ ] **Step 3: Add the new fn**

Place adjacent to `load_modules_with`:

```rust
/// pd.1: extract the validation + registry-construction tail of
/// `load_workspace_with` into a public fn that operates on a pre-assembled
/// modules map. The caller (typically `surface::load_workspace`, post-pd.2)
/// is responsible for injecting any implicit modules (e.g. prelude) into
/// `modules` BEFORE calling this fn, AND for naming those implicit modules
/// in `implicit_imports` so the diagnostic helpers (`check_class_ref`,
/// `check_type_con_name`) include them as fallback candidates.
///
/// Runs the three-stage pipeline:
/// 1. `validate_canonical_type_names` (with `implicit_imports`)
/// 2. `validate_classdefs` (no `implicit_imports` — does not consume it)
/// 3. `build_registry`
pub fn build_workspace(
    entry_name: String,
    root_dir: PathBuf,
    modules: BTreeMap<String, Module>,
    implicit_imports: &[&str],
) -> Result<Workspace, WorkspaceLoadError> {
    validate_canonical_type_names(&modules, implicit_imports)?;
    validate_classdefs(&modules)?;
    let registry = build_registry(&modules)?;

    Ok(Workspace {
        entry: entry_name,
        modules,
        root_dir,
        registry,
    })
}
```

- [ ] **Step 4: Run test to verify it fails (with a different error)**

Run: `cargo test -p ailang-core build_workspace_accepts_assembled_modules_and_runs_validation`
Expected: FAIL with "this function takes 1 argument but 2 arguments were
supplied" (because `validate_canonical_type_names` still has the old
single-arg signature — Task 3 adds the parameter). The test compiles
through `build_workspace` but fails at the inner call site.

If the failure mode is different (e.g. trait bound), inspect — the
compile-error message must point at `validate_canonical_type_names`'s
arity, not at anything else.

- [ ] **Step 5: Verify Task 2 is wired (deferring green to Task 3)**

This task ends RED-on-purpose. Task 3 lands the parameter on
`validate_canonical_type_names` and turns Task 2's test green at the
end of Task 3.

---

### Task 3: Thread `implicit_imports: &[&str]` through `validate_canonical_type_names`, `check_class_ref`, `check_type_con_name`

**Files:**
- Modify: `crates/ailang-core/src/workspace.rs:925-1097` — three signatures
  + ~6 internal call sites in `validate_canonical_type_names` + two
  fallback-iter rewrites in the diagnostic helpers.

- [ ] **Step 1: Write the failing test for the new threading semantics**

Place in `#[cfg(test)] mod tests`. The test exercises the parameterisation
end-to-end: with `implicit_imports = &["prelude"]` the fallback fires
(today's behaviour); with `implicit_imports = &[]` the same fixture
returns `BareCrossModuleClassRef` with NO `prelude.X` candidate.

```rust
#[test]
fn implicit_imports_arg_drives_prelude_fallback_in_diagnostics() {
    // Build a 2-module workspace where module "main" has a bare class-ref
    // "Eq" that resolves only via prelude.
    let mut modules = BTreeMap::new();
    modules.insert("main".to_string(), module_with_bare_classref("main", "Eq"));
    modules.insert(
        "prelude".to_string(),
        module_with_class_def("prelude", "Eq", "a"),
    );

    // With implicit_imports = &["prelude"] — prelude.Eq appears in candidates.
    let err_with = validate_canonical_type_names(&modules, &["prelude"]).unwrap_err();
    match err_with {
        WorkspaceLoadError::BareCrossModuleClassRef { ref candidates, .. } => {
            assert!(
                candidates.iter().any(|c| c == "prelude.Eq"),
                "expected prelude.Eq in candidates, got {:?}", candidates
            );
        }
        other => panic!("expected BareCrossModuleClassRef, got {other:?}"),
    }

    // With implicit_imports = &[] — prelude.Eq does NOT appear.
    let err_without = validate_canonical_type_names(&modules, &[]).unwrap_err();
    match err_without {
        WorkspaceLoadError::BareCrossModuleClassRef { ref candidates, .. } => {
            assert!(
                !candidates.iter().any(|c| c == "prelude.Eq"),
                "expected NO prelude.Eq in candidates, got {:?}", candidates
            );
        }
        other => panic!("expected BareCrossModuleClassRef, got {other:?}"),
    }
}
```

The helpers `module_with_bare_classref` and `module_with_class_def` may
need to be added if no in-tree analogue exists. Keep them in the same
`mod tests` block. Suggest:

```rust
fn module_with_bare_classref(name: &str, class_ref: &str) -> Module {
    Module {
        name: name.to_string(),
        imports: vec![],
        defs: vec![Def::Instance(InstanceDef {
            class: class_ref.to_string(),
            ty: Type::Con { name: format!("{name}.Foo"), args: vec![] },
            methods: vec![],
            doc: None,
        })],
    }
}

fn module_with_class_def(name: &str, class_name: &str, param: &str) -> Module {
    Module {
        name: name.to_string(),
        imports: vec![],
        defs: vec![Def::Class(ClassDef {
            name: class_name.to_string(),
            param: param.to_string(),
            superclasses: vec![],
            methods: vec![],
            doc: None,
        })],
    }
}
```

If similar helpers already exist in the test block, use them and skip the
helper additions.

- [ ] **Step 2: Run test to verify it fails**

Run: `cargo test -p ailang-core implicit_imports_arg_drives_prelude_fallback_in_diagnostics`
Expected: FAIL with "this function takes 1 argument but 2 arguments were
supplied" — `validate_canonical_type_names` still has the old single-arg
signature.

- [ ] **Step 3: Add the parameter to `validate_canonical_type_names`**

Edit the signature at line 938-940. Old:

```rust
pub(crate) fn validate_canonical_type_names(
    modules: &BTreeMap<String, Module>,
) -> Result<(), WorkspaceLoadError> {
```

New:

```rust
pub(crate) fn validate_canonical_type_names(
    modules: &BTreeMap<String, Module>,
    implicit_imports: &[&str],
) -> Result<(), WorkspaceLoadError> {
```

- [ ] **Step 4: Add the parameter to `check_class_ref` and `check_type_con_name`**

`check_class_ref` (signature at lines 1041-1046). Old:

```rust
fn check_class_ref(
    class_ref: &str,
    owning_module: &str,
    local_classes: &BTreeMap<String, BTreeSet<String>>,
    import_names: &[&str],
) -> Result<(), WorkspaceLoadError> {
```

New:

```rust
fn check_class_ref(
    class_ref: &str,
    owning_module: &str,
    local_classes: &BTreeMap<String, BTreeSet<String>>,
    import_names: &[&str],
    implicit_imports: &[&str],
) -> Result<(), WorkspaceLoadError> {
```

`check_type_con_name` (signature at lines 1101-1106). Old:

```rust
fn check_type_con_name(
    name: &str,
    owning_module: &str,
    local_types: &BTreeMap<String, BTreeSet<String>>,
    import_names: &[&str],
) -> Result<(), WorkspaceLoadError> {
```

New:

```rust
fn check_type_con_name(
    name: &str,
    owning_module: &str,
    local_types: &BTreeMap<String, BTreeSet<String>>,
    import_names: &[&str],
    implicit_imports: &[&str],
) -> Result<(), WorkspaceLoadError> {
```

- [ ] **Step 5: Replace the literal-`"prelude"` fallback in `check_class_ref`**

At lines 1084-1091, replace:

```rust
    if !import_names.contains(&"prelude")
        && local_classes
            .get("prelude")
            .map(|s| s.contains(class_ref))
            .unwrap_or(false)
    {
        candidates.push(format!("prelude.{class_ref}"));
    }
```

with:

```rust
    for implicit in implicit_imports {
        if import_names.contains(implicit) {
            continue; // already added above
        }
        if local_classes
            .get(*implicit)
            .map(|s| s.contains(class_ref))
            .unwrap_or(false)
        {
            candidates.push(format!("{implicit}.{class_ref}"));
        }
    }
```

- [ ] **Step 6: Replace the literal-`"prelude"` fallback in `check_type_con_name`**

At lines 1148-1155, replace:

```rust
    if !import_names.contains(&"prelude")
        && local_types
            .get("prelude")
            .map(|s| s.contains(name))
            .unwrap_or(false)
    {
        candidates.push(format!("prelude.{name}"));
    }
```

with:

```rust
    for implicit in implicit_imports {
        if import_names.contains(implicit) {
            continue; // already added above
        }
        if local_types
            .get(*implicit)
            .map(|s| s.contains(name))
            .unwrap_or(false)
        {
            candidates.push(format!("{implicit}.{name}"));
        }
    }
```

- [ ] **Step 7: Update the call sites of `check_class_ref` and `check_type_con_name` inside `validate_canonical_type_names`**

Six internal call sites per recon (lines 981, 988, 998, 1002, 1007, 1015).
Each gets `implicit_imports` forwarded as the new last arg. The exact
shape of each call site varies — the change is mechanical: add
`implicit_imports` as the trailing positional arg.

Example pattern (the actual lines may differ slightly; replicate for all
six call sites):

Old:
```rust
check_type_con_name(name, owning, local_types, &import_names)?;
```

New:
```rust
check_type_con_name(name, owning, local_types, &import_names, implicit_imports)?;
```

- [ ] **Step 8: Run the new test from Step 1**

Run: `cargo test -p ailang-core implicit_imports_arg_drives_prelude_fallback_in_diagnostics`
Expected: PASS — both the with-prelude and without-prelude branches.

- [ ] **Step 9: Run Task 2's test**

Run: `cargo test -p ailang-core build_workspace_accepts_assembled_modules_and_runs_validation`
Expected: PASS — the inner `validate_canonical_type_names(&modules, implicit_imports)` call now compiles.

- [ ] **Step 10: Migrate existing direct callers of `validate_canonical_type_names`**

Recon listed ~12 tests in the `mod tests` block that call
`validate_canonical_type_names(&modules)` directly (lines 1981, 2000,
2036, 2076, 2108, 2143, 2179, 2584, 2625, 2678, 2720; plus any siblings
in 2393-2483 not enumerated). Each gets a mechanical rewrite:

Old:
```rust
validate_canonical_type_names(&modules)
```

New:
```rust
validate_canonical_type_names(&modules, &["prelude"])
```

The `&["prelude"]` matches today's hardcoded behaviour; assertions on
`prelude.X` candidate strings continue to pass.

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

Run: `cargo test -p ailang-core`
Expected: all tests pass. If a missed call site breaks compilation, find it,
add `&["prelude"]`, re-run.

---

### Task 4: Refit `load_workspace_with` as a thin compatibility shim

**Files:**
- Modify: `crates/ailang-core/src/workspace.rs:441-529` — replace the body
  of `load_workspace_with` with a 3-line composition. The doc-comment
  updates to reflect the shim role.

- [ ] **Step 1: Write the regression-pin test for the shim**

The shim must produce a `Workspace` byte-identical to what today's
`load_workspace_with` produces for the same inputs. Pin one
representative case in the `#[cfg(test)] mod tests` block:

```rust
#[test]
fn load_workspace_with_shim_preserves_today_semantics() {
    let dir = tempfile::tempdir().unwrap();
    write_module(dir.path(), "main", &[]);
    let entry = dir.path().join("main.ail.json");

    let ws = load_workspace_with(&entry, load_one).expect("load");

    assert_eq!(ws.entry, "main");
    assert!(ws.modules.contains_key("main"));
    assert!(
        ws.modules.contains_key("prelude"),
        "shim must still inject prelude"
    );
    // Module hash stability: the prelude module hash must equal what
    // today's load_prelude() produces.
    assert_eq!(
        module_hash(&ws.modules["prelude"]),
        module_hash(&load_prelude()),
    );
}
```

- [ ] **Step 2: Run test to verify it passes against today's
  implementation**

Run: `cargo test -p ailang-core load_workspace_with_shim_preserves_today_semantics`
Expected: PASS — this is the baseline before the shim refit, asserting the
test is correctly written against today's behaviour.

- [ ] **Step 3: Refit `load_workspace_with`**

Replace the body at lines 461-528 (everything inside the fn after the
signature). Old shape (~70 lines): the inline DFS + inject + validation
block. New shape:

```rust
pub fn load_workspace_with<F>(
    entry_path: &Path,
    loader: F,
) -> Result<Workspace, WorkspaceLoadError>
where
    F: Fn(&Path) -> Result<Module, WorkspaceLoadError> + Copy,
{
    // pd.1: thin compatibility shim composed of the new
    // `load_modules_with` + `build_workspace` plus the prelude inject.
    // pd.2 will rewire `surface::load_workspace` to call the new fns
    // directly and remove this shim.
    let (entry_name, root_dir, mut modules) = load_modules_with(entry_path, loader)?;

    // Iter 23.1 (preserved through the shim): the prelude module is
    // implicitly part of every workspace. A user module of the same name
    // would shadow; reject explicitly.
    if modules.contains_key("prelude") {
        return Err(WorkspaceLoadError::ReservedModuleName {
            name: "prelude".to_string(),
        });
    }
    modules.insert("prelude".to_string(), load_prelude());

    build_workspace(entry_name, root_dir, modules, &["prelude"])
}
```

The doc-comment above the fn (lines 441-454) updates to reflect the shim
role:

```rust
/// pd.1: thin compatibility shim composed of `load_modules_with` +
/// `build_workspace` plus the prelude inject. Preserves today's
/// `load_workspace_with` semantics so surface (`crates/ailang-surface/src/loader.rs`)
/// stays unchanged in pd.1. pd.2 will rewire surface to call
/// `load_modules_with` and `build_workspace` directly and retire this
/// shim along with the embedded `PRELUDE_JSON` constant.
///
/// Algorithm: DFS over `imports` via `load_modules_with`, then inject
/// the prelude (rejecting collision with a user module of the same
/// name), then validate + build the typeclass registry via
/// `build_workspace`.
```

- [ ] **Step 4: Run the regression-pin test**

Run: `cargo test -p ailang-core load_workspace_with_shim_preserves_today_semantics`
Expected: PASS — the shim produces the same `Workspace`.

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

Run: `cargo test -p ailang-core`
Expected: all tests pass. The shim is a pure refactor; every existing
test that called `load_workspace_with` continues to see the same
behaviour.

---

### Task 5: Retire `pub fn load_workspace` (the JSON-only legacy wrapper)

**Files:**
- Modify: `crates/ailang-core/src/workspace.rs:437-439` — delete the fn.
- Modify: `crates/ailang-core/src/workspace.rs:1-32` — update the
  module-level rustdoc.
- Modify: `crates/ailang-core/src/lib.rs` — remove the re-export of
  `load_workspace` if present.

- [ ] **Step 1: Verify no in-tree caller**

Run: `git grep -n 'ailang_core::load_workspace\b' -- '*.rs' '*.toml' | grep -v 'load_workspace_with'`
Expected: no production hits. Doc-comment hits in `crates/ailang-core/src/workspace.rs:1-32`
and other `//!` / `///` references are acceptable; they'll be cleaned up
in Step 4.

If a real caller appears, STOP and report — the spec assumed zero
callers per the grounding-check report.

- [ ] **Step 2: Delete the fn**

Remove lines 437-439:

```rust
pub fn load_workspace(entry_path: &Path) -> Result<Workspace, WorkspaceLoadError> {
    load_workspace_with(entry_path, load_one)
}
```

- [ ] **Step 3: Remove the re-export from `lib.rs`**

Inspect `crates/ailang-core/src/lib.rs`. If it contains
`pub use workspace::load_workspace;` or similar, delete that line. If
the re-export is `pub use workspace::*;`, no edit needed; if it names
`load_workspace` explicitly, delete the entry.

- [ ] **Step 4: Update the module rustdoc**

`crates/ailang-core/src/workspace.rs:1-32` — the example block calls
`ailang_core::load_workspace(...)`. Rewrite the example to use the
shim:

Old (approximate — verify with the file):
```rust
//! ```no_run
//! use ailang_core::load_workspace;
//! let ws = load_workspace(...).unwrap();
//! ```
```

New:
```rust
//! ```no_run
//! // pd.2 will move the public entry point to ailang-surface;
//! // pd.1 keeps `load_workspace_with` as the single core entry point.
//! use ailang_core::workspace::{load_workspace_with, load_one};
//! let ws = load_workspace_with(/* path */&std::path::PathBuf::from("examples/foo.ail.json"), load_one).unwrap();
//! ```
```

The "single entry point" wording at line 8 (if present) updates
correspondingly.

- [ ] **Step 5: Run cargo check + tests**

Run: `cargo check -p ailang-core && cargo test -p ailang-core`
Expected: clean compile, all tests green. The doc-test in the rustdoc
example may or may not run depending on the `no_run` attribute; if it
runs and fails, mark it `no_run` or `ignore`.

---

### Task 6: Full workspace test suite + bench regressions

**Files:** none directly — verification step.

- [ ] **Step 1: Run the full workspace test suite**

Run: `cargo test --workspace`
Expected: all tests green. `ailang-surface`, `ailang-check`, `ailang-codegen`,
and `ail` tests are unaffected because the shim preserves the public
behaviour.

If a test fails, the most likely cause is a missed call site for
`validate_canonical_type_names` outside the `mod tests` block (Task 3
Step 10). Find it via `git grep -n 'validate_canonical_type_names('`
and migrate.

- [ ] **Step 2: Run the regression baselines**

Run: `python bench/check.py && python bench/compile_check.py && python bench/cross_lang.py`
Expected: all three exit code 0. None of pd.1's changes alter compiled
binary output or check semantics; baselines should be unchanged.

- [ ] **Step 3: Confirm core's `src/` literal-`"prelude"` count dropped from 8 to 4**

Run: `git grep -c '"prelude"' crates/ailang-core/src/workspace.rs`
Expected: count drops from the pre-pd.1 baseline (8) to 4. The remaining
4 are: line 498 (`if modules.contains_key("prelude")` in the shim),
line 500 (`name: "prelude".to_string()` in the shim's err return), line
504 (`modules.insert("prelude".to_string(), load_prelude())` in the
shim), and any survivor in test code. The 4 diagnostic-fallback
occurrences (1084 / 1086 / 1148 / 1150) MUST be gone.

If any of the four diagnostic occurrences survives, Task 3 Steps 5-6
were incomplete — find and remove.

- [ ] **Step 4: Confirm pd.1 acceptance criterion**

Per the spec (§Acceptance criteria, items 4 + 5 are pd.1's portion;
items 1, 2, 3, 6, 7 belong to pd.2/pd.3):

- `cargo test --workspace` green ✓ (Step 1)
- `bench/check.py`, `bench/compile_check.py`, `bench/cross_lang.py`
  green at unchanged baselines ✓ (Step 2)

The remaining acceptance items (delete `prelude.ail.json`, zero
`include_str!`-of-prelude.ail.json, zero literal-`"prelude"` in
`core/src/`, carve_out_inventory update, form-a §C4 (b) update)
land in pd.2 + pd.3.

---

## Out of scope for pd.1

The following spec items are deferred to pd.2 / pd.3 and MUST NOT be
touched in pd.1:

- Adding `PRELUDE_AIL: &str = include_str!("../../../examples/prelude.ail")`
  or `parse_prelude` to `crates/ailang-surface/src/loader.rs` (pd.2).
- Rewriting `surface::load_workspace` to call the new core fns directly
  (pd.2) — surface stays calling `load_workspace_with` via the shim in
  pd.1.
- Removing the prelude embed (`PRELUDE_JSON` const + `load_prelude` fn)
  from core (pd.2 — once surface owns the embed, the shim can drop them).
- The cross-form-identity preflight test (pd.2 — gates the embed swap).
- Deleting `examples/prelude.ail.json` (pd.3).
- Deleting the defensive include in `crates/ail/src/main.rs:472-484` (pd.3).
- Updating `crates/ailang-core/tests/carve_out_inventory.rs` (pd.3).
- Updating `docs/specs/2026-05-13-form-a-default-authoring.md` §C4 (b)
  (pd.3).

A pd.1 implementer who finds themselves about to edit any of the above
files should STOP and re-read the parent spec's iteration sketch — the
work belongs to a later iter.
