// Author B's generic `Box` — two s64 fields (size 16) whose `tag` returns
// `self.x + 2`. Same template NAME as A's, different layout/body; it wins the
// global last-wins `fn_ast_map["Box.tag"]`, so the alias over `a.Box` must NOT
// dispatch to it.
Box :: struct($T: Type) {
    x: T;
    y: T;

    tag :: (self: *Box) -> T {
        self.x + 2
    }
}