struct Fst {
mut:
    f fn () int
}

fn setfn(mut f Fst) {
    mut i := 0
    f.f = fn () int {
        return 5
    }
    defer {
        if i > 0 {
            f.f = fn () int {
                a := 0
                defer {
                    assert a == 0
                }
                return 7
            }
        }
    }
    i = 1
}

fn test_nested_defer() {
    mut g := Fst{}
    setfn(mut g)
    x := g.f()
    assert x == 7
}