typedef list[T] = (
    count size,
    count capacity,
    T#[capacity]^ elements,
);

typedef incomplete pair[T,U] = (
    T first,
    U second,
);



list[int] a;
list[list[int]] b;
pair[list[int],list[int]]^ c;
pair[list[int],int] d;
pair[pair[list[int],list[int]], pair[pair[int,int],list[int]]] e;