Files
AILang/crates/ail/tests/polyfn_dot_qualified_branch_pin.rs
T
Brummel 4e8447d15d iter 24.tidy: close 5 actionable drift items from audit-24
Documents the three iter-24.3 strengthenings as load-bearing
invariants and tightens two error-handling sites:

T1: DESIGN.md gains new subsection §Cross-module references in
synthesised bodies (between Resolution-and-monomorphisation and
Defaults-and-superclasses) documenting three invariants installed
in iter 24.3 — (1) MonoTarget::FreeFn::type_args carries canonical
types post-collection via normalize_type_for_lookup; (2) post-mono
synthesised body cross-module refs may bypass the source template's
import_map (codegen falls back to module_user_fns / module_def_ail_types);
(3) FreeFnCall synth pushes one ResidualConstraint per declared
forall-constraint with rigid vars substituted by fresh metavars.

T2: codegen_import_map_fallback_pin.rs (integration test) asserts
the synthesised prelude.print__<IntBox> body references
show_user_adt.show__<IntBox> AND prelude module's imports do not
contain show_user_adt — proving the cross-module ref bypasses
import_map at codegen.

T3: polyfn_dot_qualified_branch_pin.rs (integration test) asserts
bare-name print f (f : Int -> Int) fires exactly one no-instance
diagnostic at typecheck with zero unknown-variable diagnostics —
proving the bare-name resolution reaches the dot-qualified synth
branch where the constraint-residual push fires.

T4: check/lib.rs:2858 unwrap_or_default() replaced with .expect()
carrying the registry-coherence message — class_methods index
drift now surfaces explicitly rather than rendering NoInstance
with an empty method name.

T5: mono.rs gains apply_subst_and_normalize helper (Option<Type>
return) extracted from two byte-identical call sites at
collect_mono_targets and collect_residuals_ordered. Each call site
retains its own rigid-var / unit-default policy in the None arm
(site 1: rigid → has_rigid+break, unbound → Type::unit; site 2:
non-concrete → Type::unit). Byte-identity invariant on mono-symbol
hashes enforced by construction.

Tests: 558 passed (was 556 + 2 new pins). No production semantic
change — pure documentation + test pin + error-handling tightening
+ helper refactor. bench/cross_lang exit 0; bench/compile_check +
bench/check exit 0 this run (latency.implicit_at_rc / latency.explicit_at_rc /
bench_list_sum.bump_s noise envelope unobserved, lineage continues
at 10th consecutive observation without firing this run).
2026-05-13 04:28:15 +02:00

72 lines
3.1 KiB
Rust

//! Pin for the iter-24.3 FreeFnCall constraint-residual-push
//! invariant (DESIGN.md §"Cross-module references in synthesised
//! bodies" invariant 3).
//!
//! Property protected: bare-name references to polymorphic free fns
//! that resolve through the auto-injected-prelude path AT THE
//! DOT-QUALIFIED SYNTH BRANCH push residuals for the fn's declared
//! constraints. The discharge loop then fires `NoInstance` at
//! typecheck if no instance ships for the unified concrete type.
//!
//! Failure mode this pin catches: a future refactor changes the
//! prelude auto-injection resolution path so that bare-name `print`
//! reaches synth via a different branch (e.g. locals, env.module_globals
//! direct hit) that does NOT push residuals. Without this pin, the
//! regression surfaces as `unknown variable: show` from codegen for
//! the negative case — confusing diagnostic, hard to bisect.
use ailang_check::check_workspace;
use ailang_core::workspace::load_workspace;
use std::path::PathBuf;
fn fixture_path() -> PathBuf {
PathBuf::from(env!("CARGO_MANIFEST_DIR"))
.join("../../examples")
.join("show_no_instance.ail.json")
}
#[test]
fn bare_name_polyfn_fires_typecheck_no_instance_not_codegen_unknown_var() {
// The fixture calls `print f` bare-name (no `prelude.` qualifier)
// where `f : Int -> Int`. The auto-injected-prelude resolution
// must route this through the dot-qualified synth branch so that
// the `Show a` declared constraint of `print` produces a residual,
// and the discharge loop fires `no-instance`.
let ws = load_workspace(&fixture_path()).expect("workspace loads");
let diags = check_workspace(&ws);
// Exactly one `no-instance` diagnostic — proves:
// (a) the bare-name `print` resolved (was not "unknown variable")
// (b) the resolution reached the dot-qualified synth branch
// which pushes the declared-constraint residual
// (c) the discharge loop ran with the residual and fired the
// NoInstance because no `Show (Int -> Int)` instance exists.
let no_inst: Vec<_> = diags.iter().filter(|d| d.code == "no-instance").collect();
assert_eq!(
no_inst.len(),
1,
"expected exactly one 'no-instance' diagnostic — got {} (all diags: {diags:?})",
no_inst.len()
);
// No "unknown variable" or other codegen-grade errors at typecheck:
// if the residual push did NOT fire, the typecheck would pass
// silently and the error would only surface at codegen.
let unknown_vars: Vec<_> = diags
.iter()
.filter(|d| {
d.code == "unknown-variable"
|| d.message.contains("unknown variable")
|| d.code == "internal"
})
.collect();
assert!(
unknown_vars.is_empty(),
"expected zero 'unknown variable' or 'internal' diagnostics at typecheck — \
got {} (all diags: {diags:?}). If this fires, the bare-name `print` \
resolution bypassed the dot-qualified synth branch and the constraint \
residual was never pushed.",
unknown_vars.len()
);
}