iter 22b.3.2: mono_symbol — primitive surface forms + hash for compound

crates/ail/tests/typeclass_22b3.rs

@@ -5,6 +5,7 @@
 //! `examples_dir()` pattern — `cargo test`-cwd is the crate dir,
 //! the fixtures live in `<repo>/examples/`.
 
+use ailang_core::ast::Type;
 use std::path::PathBuf;
 
 fn examples_dir() -> PathBuf {
@@ -93,3 +94,44 @@ fn monomorphise_workspace_is_identity_when_no_concrete_call_sites() {
         );
     }
 }
+
+#[test]
+fn mono_symbol_primitive_types_use_surface_form() {
+    // Primitive-type forms must be human-readable in diagnostics
+    // and ABI symbols. Per the spec's mono-symbol naming guidance:
+    // <method>#<surface-name> for primitives.
+    let int_ty = Type::int();
+    let bool_ty = Type::bool_();
+    let str_ty = Type::str_();
+    let unit_ty = Type::unit();
+
+    assert_eq!(ailang_check::mono::mono_symbol("show", &int_ty), "show#Int");
+    assert_eq!(ailang_check::mono::mono_symbol("eq", &bool_ty), "eq#Bool");
+    assert_eq!(ailang_check::mono::mono_symbol("show", &str_ty), "show#Str");
+    assert_eq!(ailang_check::mono::mono_symbol("foo", &unit_ty), "foo#Unit");
+}
+
+#[test]
+fn mono_symbol_compound_type_uses_hash_suffix() {
+    // Compound types fall through to canonical type_hash with an
+    // 8-hex-char prefix. Stability matters more than legibility
+    // here — same input must produce the same name across runs.
+    let pair_ty = Type::Con {
+        name: "Pair".into(),
+        args: vec![Type::int(), Type::bool_()],
+    };
+    let name = ailang_check::mono::mono_symbol("show", &pair_ty);
+
+    // Format: `show#<8-hex-chars>`.
+    assert!(name.starts_with("show#"), "name = {name}");
+    let suffix = &name["show#".len()..];
+    assert_eq!(suffix.len(), 8, "compound suffix is 8 hex chars: {suffix}");
+    assert!(
+        suffix.chars().all(|c| c.is_ascii_hexdigit()),
+        "compound suffix must be hex: {suffix}"
+    );
+
+    // Stability: a second call with the same type produces the same name.
+    let again = ailang_check::mono::mono_symbol("show", &pair_ty);
+    assert_eq!(name, again, "mono_symbol must be deterministic");
+}