@[heap]
struct Abc {
mut:
    n int
}

struct St {
    Abc
}

struct Qwe {
mut:
    f f64
    a Abc
}

fn pass_abc(q &Abc) &Abc {
    return q
}

fn pass_st(q &St) &St {
    return q
}

fn pass_qwe(q &Qwe) &Qwe {
    return q
}

fn get_ref_structs() (&Abc, &St, &Qwe) {
    a := Abc{
        n: 3
    }
    b := St{Abc{
        n: 7
    }}
    x := Qwe{
        f: 12.25
        a: Abc{
            n: 23
        }
    }
    aa := pass_abc(&a)
    bb := pass_st(&b)
    xx := pass_qwe(&x)
    return aa, bb, xx
}

fn overwrite_stack() f64 {
    a := 12.5
    b := 3.5
    c := a + b
    return c
}

fn test_ref_struct() {
    u, v, w := get_ref_structs()
    d := overwrite_stack()
    assert u.n == 3
    assert v.n == 7
    assert w.a.n == 23
    assert d == 16.0
}

fn return_heap_obj_value_as_ref(qpast Qwe) &Qwe {
    return &qpast
}

fn test_value_ref_heap_struct() {
    mut x := Qwe{
        f: -13.25
        a: Abc{
            n: -129
        }
    }
    y := return_heap_obj_value_as_ref(x)
    x.f = 22.0625
    d := overwrite_stack()
    assert typeof(y).name == '&Qwe'
    assert x.f == 22.0625
    assert x.a.n == -129
    assert y.f == -13.25
    assert y.a.n == -129
    assert d == 16.0
}

struct NotHeap {
mut:
    f f64
}

fn return_struct_value_as_ref(q NotHeap) &NotHeap {
    return &q
}

fn test_value_ref_struct() {
    mut x := NotHeap{
        f: -17.125
    }
    y := return_struct_value_as_ref(x)
    x.f = 91.0625
    d := overwrite_stack()
    assert typeof(y).name == '&NotHeap'
    assert y.f == -17.125
    assert x.f == 91.0625
    assert d == 16.0
}

fn get_int_ref() &int {
    i := 49154
    return &i
}

fn test_int_ref() {
    iptr := get_int_ref()
    assert typeof(iptr).name == '&int'
    d := overwrite_stack()
    assert *iptr == 49154
    assert d == 16.0
}

fn pass_f64_as_ref(f f64) &f64 {
    return &f
}

fn test_value_as_ref() {
    mut x := -31.75
    y := pass_f64_as_ref(x)
    assert typeof(y).name == '&f64'
    x = 23.0625
    d := overwrite_stack()
    assert x == 23.0625
    assert *y == -31.75
    assert d == 16.0
}