iter 24.3: fn print + E2E + 3 compiler-path repairs; milestone 24 close

Ships fn print : forall a. Show a => (a borrow) -> () !IO in the
prelude with explicit-let body \\x -> let s = show x in do
io/print_str s. Three new E2E fixtures + tests verify the full
path:

- show_print_smoke: 4 primitives smoke (print 42 / true / 'hello' /
  3.14) — compile, run, expected stdout
- show_user_adt: data IntBox + instance prelude.Show IntBox +
  print (MkIntBox 7) — stdout '7'
- show_no_instance: let f : Int -> Int = \\x -> x in do print f —
  fires Show-aware NoInstance with DESIGN.md §Prelude(built-in)
  classes cross-reference

IR-shape pin in print_mono_body_shape.rs asserts post-mono
print__Int.body is structurally Term::Let → App(show__Int) →
Do(io/print_str). Protects the explicit let-binder for the heap-Str
RC discipline per eob.1 Str carve-out.

Three plan-defects-fixed-inline surfaced during user-ADT E2E,
necessary repairs to make the spec's stated user-ADT trajectory
work end-to-end:

(a) mono.rs (2 sites): MonoTarget::FreeFn::type_args were carrying
    bare type-cons references; normalised to canonical
    <owner>.<bare> form via workspace_registry.normalize_type_for_lookup
    so synthesised cross-module bodies' post-mono walks reach the
    registry-keyed instance entries. Symmetric to the existing
    class-method-arm normalisation.

(b) codegen/lib.rs (3 sites: resolve_top_level_fn, lower_app
    cross-module arm, synth_with_extras Var arm): post-mono
    synthesised bodies may carry cross-module references to modules
    their source template didn't import (prelude.print__<UserType>
    references show_user_adt.show__<UserType> even though prelude
    does not import user modules). Fall back to direct
    module_user_fns lookup when prefix not in import_map. Both
    ends were independently typechecked before mono ran; the
    cross-module ref is created by mono not by source.

(c) lib.rs synth FreeFnCall arm: walked Type::Forall.constraints,
    substituted rigid vars with fresh metavars, pushed one
    ResidualConstraint per declared constraint. Without this,
    print f at Int -> Int would silently typecheck and fail with
    a confusing 'unknown variable: show' at codegen rather than
    fire the right typecheck-time NoInstance diagnostic.

NoInstance Float-aware arm in check/lib.rs:770-779 extended with
a parallel class == 'prelude.Show' branch that cross-references
DESIGN.md §Prelude(built-in) classes verbatim. Negative-fixture
test asserts code 'no-instance' + Show substring + Prelude-(built-in)-
classes substring.

DESIGN.md §Prelude(built-in) classes milestone-24 paragraph flips
fn print from 'ships in 24.3' to 'shipped in iter 24.3' with body
shape + pin file reference. §Float semantics gains a Show-Float
NaN-spelling cross-reference paragraph linking show 1.5 / show nan /
show inf to instance Show Float via float_to_str.

Roadmap P1 'Post-22 Prelude — Show + print rewire' flipped to [x]
with closing summary naming all three shipped iters (24.1 / 24.2 /
24.3). New P2 entry 'Retire io/print_int|bool|float effect-ops +
migrate example corpus to print' inserted at top of P2.

Tests: 556 passed (was 552 + 4 new). bench/cross_lang exit 0;
bench/compile_check + bench/check exit 1 on documented noise-class
metrics per the audit-cma lineage envelope (8th consecutive
audit-grade observation, baseline pristine per conservative-call).

Milestone 24 closes structurally with this iter. Standard audit
pipeline next.
This commit is contained in:
2026-05-13 04:07:36 +02:00
parent c04c07fe86
commit 246b5c7455
14 changed files with 858 additions and 43 deletions
+86
View File
@@ -0,0 +1,86 @@
//! IR-shape pin for milestone 24.3's `print` polymorphic free fn.
//!
//! Property protected: the post-mono `print__Int` `Def::Fn.body` is
//! structurally `Term::Let { name: "s", value: App(show__Int, [x]),
//! body: Term::Do { op: "io/print_str", args: [s] } }`. The explicit
//! let-binder around `show__Int x` is load-bearing for the heap-Str RC
//! discipline (eob.1 Str carve-out at `drop_symbol_for_binder` requires
//! a let-binder to attach the rc-dec to). If a future codegen / mono
//! refactor inlines the let-binder away, this pin fires and surfaces
//! the regression BEFORE the E2E runtime stats produce a confusing
//! "memory leak" diagnostic.
//!
//! Note: `FnDef.body: Term` is the *inner* function body — top-level
//! fns carry their parameter list separately on `FnDef.params`, so no
//! outer `Term::Lam` wraps the body. This contrasts with instance
//! method bodies (which carry a `Term::Lam` because they are anonymous
//! function values inside `InstanceMethod.body`).
use ailang_core::ast::{Def, Term};
use ailang_core::workspace::load_workspace;
use std::path::PathBuf;
fn fixture_path() -> PathBuf {
let mut d = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
d.pop();
d.pop();
d.join("examples").join("show_print_smoke.ail.json")
}
#[test]
fn print_int_body_preserves_explicit_let_binder() {
let ws = load_workspace(&fixture_path()).expect("workspace loads");
let diags = ailang_check::check_workspace(&ws);
assert!(diags.is_empty(), "typecheck diagnostics: {diags:?}");
let post_mono = ailang_check::monomorphise_workspace(&ws).expect("mono green");
let prelude_mod = post_mono
.modules
.get("prelude")
.expect("prelude module present");
let print_int = prelude_mod
.defs
.iter()
.find_map(|d| match d {
Def::Fn(f) if f.name == "print__Int" => Some(f),
_ => None,
})
.expect("print__Int mono symbol not found in prelude module");
// Body shape: Term::Let { name: "s",
// value: Term::App(show__Int, [x]),
// body: Term::Do { op: "io/print_str", args: [s] } }
let (let_value, let_body) = match &print_int.body {
Term::Let { name, value, body } => {
assert_eq!(name, "s", "let-binder name expected 's', got {name:?}");
(value.as_ref(), body.as_ref())
}
other => panic!(
"print__Int.body is not Term::Let — let-binder was optimised away or never inserted. Got: {other:?}"
),
};
// Inner App should reference show__Int (post-mono symbol).
let app_fn = match let_value {
Term::App { callee, .. } => callee.as_ref(),
other => panic!("print__Int let-value is not Term::App, got: {other:?}"),
};
let app_fn_name = match app_fn {
Term::Var { name } => name,
other => panic!("let-value's fn position is not Term::Var, got: {other:?}"),
};
assert_eq!(
app_fn_name, "show__Int",
"post-mono let-value should call show__Int, got: {app_fn_name}"
);
// Inner body should be a Do invoking io/print_str.
match let_body {
Term::Do { op, args, .. } => {
assert_eq!(op, "io/print_str", "let-body Do op expected 'io/print_str', got {op:?}");
assert_eq!(args.len(), 1, "io/print_str expects 1 arg, got {}", args.len());
}
other => panic!("print__Int let-body is not Term::Do, got: {other:?}"),
}
}
+51
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@@ -0,0 +1,51 @@
//! Pins the Show-aware `no-instance` diagnostic shipped in milestone 24.3.
//!
//! Property protected: calling `print` on a function type fires the
//! `no-instance` diagnostic with a Show-aware message that
//! cross-references DESIGN.md §"Prelude (built-in) classes", so the
//! LLM author immediately learns which types ship with built-in Show
//! and how to declare their own instance for a user type.
use ailang_check::check_workspace;
use ailang_core::workspace::load_workspace;
use std::path::PathBuf;
fn fixture(name: &str) -> PathBuf {
PathBuf::from(env!("CARGO_MANIFEST_DIR"))
.join("../../examples")
.join(name)
}
#[test]
fn print_on_fn_type_fires_show_aware_no_instance() {
let ws = load_workspace(&fixture("show_no_instance.ail.json")).expect("load");
let diags = check_workspace(&ws);
assert!(
!diags.is_empty(),
"expected NoInstance Show diagnostic, got no diagnostics"
);
let no_inst = diags
.iter()
.find(|d| d.code == "no-instance")
.unwrap_or_else(|| {
panic!("expected diagnostic with code 'no-instance', got: {diags:#?}")
});
// Must mention Show.
assert!(
no_inst.message.contains("Show"),
"expected Show-aware NoInstance diagnostic, got message: {:?}",
no_inst.message
);
// Must cross-reference DESIGN.md §"Prelude (built-in) classes"
// verbatim — that's the canonical anchor naming which types
// ship with Show.
assert!(
no_inst.message.contains("Prelude (built-in) classes"),
"expected DESIGN.md §Prelude (built-in) classes cross-reference, got message: {:?}",
no_inst.message
);
}
+74
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@@ -0,0 +1,74 @@
//! End-to-end tests for the `print` polymorphic helper shipped in
//! milestone 24.3.
//!
//! Each test compiles a `.ail.json` workspace via the `ail build`
//! subcommand, runs the resulting native binary, and asserts on stdout.
//!
//! Properties protected:
//! - `print_primitives_smoke_runs_end_to_end`: `print` at four primitive
//! types (Int / Bool / Str / Float) emits the expected textual
//! representation of each value via the prelude Show instances +
//! `io/print_str`. The four `print__T` mono symbols synthesise from
//! the prelude `instance prelude.Show T` bodies and route through the
//! corresponding `<T>_to_str` runtime primitive.
//! - `print_user_adt_runs_end_to_end`: `print` composes with a
//! user-declared `instance prelude.Show IntBox` to emit a user-ADT's
//! structural representation. Confirms that the post-mono synthesised
//! `print__<UserType>` body's nested `show x` call rewrites to the
//! user instance's `show__<UserType>` mono symbol and that the
//! cross-module reference from `prelude.print__<UserType>` to
//! `<user_module>.show__<UserType>` lowers cleanly through codegen.
use std::path::PathBuf;
use std::process::Command;
fn fixture_path(name: &str) -> PathBuf {
PathBuf::from(env!("CARGO_MANIFEST_DIR"))
.join("../../examples")
.join(name)
}
fn build_and_run(fixture: &str) -> String {
let src = fixture_path(fixture);
let out = std::env::temp_dir().join(format!("ail_{}.bin", fixture.replace('.', "_")));
let build = Command::new(env!("CARGO_BIN_EXE_ail"))
.args(["build", src.to_str().unwrap(), "-o", out.to_str().unwrap()])
.output()
.expect("ail build");
assert!(
build.status.success(),
"ail build failed for {fixture}:\nstdout: {}\nstderr: {}",
String::from_utf8_lossy(&build.stdout),
String::from_utf8_lossy(&build.stderr),
);
let run = Command::new(&out).output().expect("run binary");
assert!(
run.status.success(),
"binary exited non-zero:\nstdout: {}\nstderr: {}",
String::from_utf8_lossy(&run.stdout),
String::from_utf8_lossy(&run.stderr),
);
String::from_utf8_lossy(&run.stdout).trim().to_string()
}
#[test]
fn print_primitives_smoke_runs_end_to_end() {
let stdout = build_and_run("show_print_smoke.ail.json");
// print 42 → "42\n" (int_to_str + puts)
// print true → "true\n" (bool_to_str + puts)
// print "hello" → "hello\n" (str_clone + puts)
// print 3.14 → "3.14\n" (float_to_str / libc %g + puts)
// puts emits each Str + a trailing newline; trimmed output is
// "42\ntrue\nhello\n3.14".
assert_eq!(stdout, "42\ntrue\nhello\n3.14", "got: {stdout:?}");
}
#[test]
fn print_user_adt_runs_end_to_end() {
let stdout = build_and_run("show_user_adt.ail.json");
// print (MkIntBox 7) → "7\n" (via user instance prelude.Show
// IntBox that unwraps via match + int_to_str).
assert_eq!(stdout, "7", "got: {stdout:?}");
}
+60 -1
View File
@@ -776,6 +776,23 @@ impl CheckError {
orderability per IEEE-754); see DESIGN.md §\"Float semantics\".",
d.message
);
} else if class == "prelude.Show" {
// Iter 24.3: Show-aware addendum on `NoInstance`. Fires
// for any type lacking a Show instance — most commonly
// a function type (`print f` where f is bare-fn-typed)
// or a user type the LLM-author forgot to give an
// instance for. Cross-references DESIGN.md §"Prelude
// (built-in) classes" so the author learns which types
// ship with built-in Show immediately.
d.message = format!(
"{} — `print` and `show` require a Show instance. \
Built-in Show ships for Int, Bool, Str, Float in \
the prelude; see DESIGN.md §\"Prelude (built-in) \
classes\". User types declare their own \
`instance prelude.Show <T>` in the type's defining \
module per Decision 11 coherence.",
d.message
);
}
}
d
@@ -2800,10 +2817,52 @@ pub(crate) fn synth(
// by bare name); the source-level `name` may be a
// dot-qualified form (`prefix.suffix`) the synth started
// with.
if let (Type::Forall { vars, constraints: _, body }, Some((owner, unqualified_name))) =
if let (Type::Forall { vars, constraints, body }, Some((owner, unqualified_name))) =
(&raw, &free_fn_owner)
{
let (metas, inst) = instantiate(vars, body, counter);
// Iter 24.3: push a residual for each declared constraint
// of the poly free fn with the rigid var substituted by
// its fresh metavar. The discharge loop at the enclosing
// `check_fn`'s post-synth phase resolves the residual
// against the workspace registry (fully-concrete after
// App-arm unification) and fires `NoInstance` if no
// instance ships for the unified type. Without this push,
// `print f` at a function type `f : Int -> Int` would
// typecheck silently — the `Show f`-shaped obligation
// would only surface at codegen as an `unknown variable`
// error from the synthesised mono body.
//
// The substitution mirrors `instantiate`'s body-side
// mapping: position-by-position pairing of `vars` with
// the freshly-generated `metas`. The discharge path
// post-`subst.apply` produces the same concrete type
// that the App-arm unified into the metavars.
let cmapping: BTreeMap<String, Type> = vars
.iter()
.cloned()
.zip(metas.iter().cloned())
.collect();
for c in constraints {
let c_class = qualify_class_ref_in_check(&c.class, owner);
let c_ty = substitute_rigids(&c.type_, &cmapping);
// Look up the class's method name via the workspace
// class index; we need it for the `ResidualConstraint`'s
// `method` field (used by `NoInstance`'s rendering).
let method_name = env
.class_methods
.iter()
.find_map(|((cls, m), _)| {
if *cls == c_class { Some(m.clone()) } else { None }
})
.unwrap_or_default();
residuals.push(ResidualConstraint {
class: c_class,
type_: c_ty,
method: method_name,
candidates: None,
});
}
free_fn_calls.push(FreeFnCall {
name: unqualified_name.clone(),
owner_module: owner.clone(),
+27 -2
View File
@@ -687,7 +687,24 @@ pub fn collect_mono_targets(
for m in &fc.metas {
let resolved = subst.apply(m);
if crate::is_fully_concrete(&resolved) {
type_args.push(resolved);
// Iter 24.3: normalise bare type-cons references to the
// canonical `<owner>.<bare>` form before they enter the
// MonoTarget. The synthesised body for a poly free fn
// lives in the fn's `owner_module` (e.g. `prelude` for
// `print`), but its `type_args` typically come from
// user-defining modules. If left bare, the synthesised
// body's `param_tys` carry bare references that later
// mono-walks (in the synthesised body's caller-module
// context — i.e. the fn's owner module) cannot resolve
// back to the registry's qualified instance key — and
// any nested class-method call (e.g. `show x` inside
// `print`'s body) silently produces no mono target,
// leaving the synthesised body referencing a bare class
// method that codegen later rejects.
let normalised = env
.workspace_registry
.normalize_type_for_lookup(module_name, &resolved);
type_args.push(normalised);
} else if contains_rigid_var(&resolved) {
has_rigid = true;
break;
@@ -1270,7 +1287,15 @@ pub(crate) fn collect_residuals_ordered(
.map(|m| {
let resolved = subst.apply(m);
if crate::is_fully_concrete(&resolved) {
resolved
// Iter 24.3: canonical-form normalisation — see
// matching site in `collect_mono_targets` for
// rationale. Must agree byte-identically with
// that site or Phase 3 rewrite cursor produces
// a mono-symbol name that differs from the
// Phase 2 synthesis name.
env
.workspace_registry
.normalize_type_for_lookup(module_name, &resolved)
} else {
Type::unit()
}
+52 -7
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@@ -1980,11 +1980,24 @@ impl<'a> Emitter<'a> {
// Logic identical to the typechecker (see `synth` for `Term::Var`).
if name.matches('.').count() == 1 {
let (prefix, suffix) = name.split_once('.').expect("checked");
let target_module = self.import_map.get(prefix).cloned().ok_or_else(|| {
CodegenError::Internal(format!(
"cross-module call `{name}`: prefix `{prefix}` not in import map"
))
})?;
// Iter 24.3: fall back to direct module-name lookup when
// the prefix isn't in the current module's import_map. A
// post-mono synthesised body may carry cross-module
// references to modules its source template didn't import
// (e.g. `prelude.print__<UserType>` synthesised in
// `prelude` calls `show_user_adt.show__<UserType>` even
// though prelude does not import user modules). See the
// matching fallback in `resolve_top_level_fn` for the
// companion change on the fn-pointer Var-resolution path.
let target_module = match self.import_map.get(prefix).cloned() {
Some(m) => m,
None if self.module_user_fns.contains_key(prefix) => prefix.to_string(),
None => {
return Err(CodegenError::Internal(format!(
"cross-module call `{name}`: prefix `{prefix}` not in import map"
)))
}
};
// iter 23.4: codegen-time poly-call dispatch removed. Post-mono
// every poly call site has been rewritten by `rewrite_mono_calls`
// to a monomorphic symbol, so the lookup-ladder below sees only
@@ -2200,7 +2213,22 @@ impl<'a> Emitter<'a> {
fn resolve_top_level_fn(&self, name: &str) -> Option<(String, FnSig)> {
if name.matches('.').count() == 1 {
let (prefix, suffix) = name.split_once('.')?;
let target = self.import_map.get(prefix)?;
// Iter 24.3: dotted form resolves through the current
// module's import_map first (the standard cross-module
// reference path). If the prefix isn't in import_map,
// fall back to a direct module-name lookup against
// `module_user_fns` — a post-mono synthesised body may
// carry cross-module references to modules its source
// template didn't import (e.g. `prelude.print__<UserType>`
// synthesised in `prelude` calls `show_user_adt.show__<UserType>`
// even though prelude does not import user modules; this is
// a valid post-mono construct because both ends were
// independently typechecked under their original module
// contexts before mono ran).
let target = match self.import_map.get(prefix) {
Some(m) => m,
None => prefix,
};
let sig = self.module_user_fns.get(target)?.get(suffix)?.clone();
return Some((format!("@ail_{target}_{suffix}_clos"), sig));
}
@@ -2748,7 +2776,24 @@ impl<'a> Emitter<'a> {
}
if name.matches('.').count() == 1 {
let (prefix, suffix) = name.split_once('.').expect("checked");
if let Some(target) = self.import_map.get(prefix) {
// Iter 24.3: try the current module's import_map
// first (standard cross-module reference), then
// fall back to a direct module-name lookup for
// post-mono synthesised cross-module references
// (see `resolve_top_level_fn` and the cross-module
// call arm in `lower_app` for matching fallbacks).
let target_opt: Option<&str> = self
.import_map
.get(prefix)
.map(|s| s.as_str())
.or_else(|| {
if self.module_def_ail_types.contains_key(prefix) {
Some(prefix)
} else {
None
}
});
if let Some(target) = target_opt {
if let Some(ty) = self
.module_def_ail_types
.get(target)