// A typed array/slice literal head (`([N]T).[…]` / `([]T).[…]`) names its
// element type exactly like a declaration annotation, so an UNDEFINED element
// type name must be rejected with the same `unknown type '<name>'` diagnostic
// the declaration path emits — NOT silently compiled.
//
// Regression (issues 0173–0175 adversarial review): the 0173 fix taught the
// lowering's `resolveArrayLiteralType` to resolve a structural `[N]?T` head,
// but for an UNDEFINED element name the resolver returned a forward-reference
// empty-struct STUB instead of `.unresolved`. So `([2]?Undefined).[…]`
// compiled silently (exit 0, "ok") with a wrong empty-struct element, where
// `x: [2]?Undefined = ---` correctly errored. The unknown-type checker
// (`semantic_diagnostics.zig` `walkBodyTypes`) now validates the array
// literal's `type_expr` head through the same `checkTypeNodeForUnknown` walk a
// declaration uses, so a genuinely-undeclared head element name is a loud,
// located error (exit 1) — never a silent empty-struct compile or a raw panic.
#import "modules/std.sx";

main :: () {
    arr := ([2]?Undefined).[ null, null ];
    print("ok\n");
}