sx/examples/generics/0211-generics-struct-alias-head.sx

// Generic-struct head aliases: `BoxAlias :: Box;` binds the alias to the
// SAME template — instantiation, methods, annotations, and alias chains all
// resolve through it. Cross-module, a facade's `Box :: r.Box;` re-export is
// the facade's OWN declaration, so it carries one flat-import level exactly
// like a plain-struct alias (companion files: -rich.sx authors the decls,
// -facade.sx re-exports them through a namespace alias).
// Regression (issue 0120): the alias head used to lower silently to an
// unresolved type and panic in the LLVM backend at instantiation.
#import "modules/std.sx";
#import "0211-generics-struct-alias-head-facade.sx";

LocalBox :: struct ($T: Type) {
    item: T;
    get :: (b: *LocalBox(T)) -> T { b.item }
}

LocalAlias :: LocalBox;
ChainAlias :: LocalAlias;

main :: () {
    // Same-file alias: instantiation + field + method.
    b := LocalAlias(i64).{ item = 3 };
    print("field: {}\n", b.item);
    print("method: {}\n", b.get());

    // Alias chain terminates at the template.
    c := ChainAlias(i64).{ item = 11 };
    print("chain: {}\n", c.item);

    // Alias as a type annotation head.
    a : LocalAlias(string) = .{ item = "ann" };
    print("annot: {}\n", a.item);

    // Cross-module re-exports carried one flat hop from the facade:
    // plain fn, plain struct (static method), and the generic head.
    print("helper: {}\n", helper());
    t := Thing.init();
    print("thing: {}\n", t.v);
    f := Box(i64).{ item = 7 };
    print("facade: {}\n", f.get());
    x : Box(string) = .{ item = "qq" };
    print("facade-annot: {}\n", x.item);
}