struct Node1 {
    data int
}

struct Node2 {
    data int
}

interface INode {
    data int
}

fn make_node(c int) !INode {
    match c {
        1 {
            return make_node1()!
        }
        2 {
            return make_node2()!
        }
        else {
            return error('invalid node type')
        }
    }
}

fn make_node_opt(c int) ?INode {
    match c {
        1 {
            return *make_node1_opt()?
        }
        2 {
            return *make_node2_opt()?
        }
        else {
            return none
        }
    }
}

fn make_node1() !&Node1 {
    return &Node1{
        data: 1
    }
}

fn make_node2() !&Node2 {
    return &Node2{
        data: 2
    }
}

fn make_node1_opt() ?&Node1 {
    return &Node1{
        data: 1
    }
}

fn make_node2_opt() ?&Node2 {
    return &Node2{
        data: 2
    }
}

fn test_main() {
    a := make_node(1)!
    dump(a)
    assert a.data == 1

    b := make_node_opt(1)?
    dump(b)
    assert a.data == 1
}