struct TestObj {
mut:
    a int
    b int
}

fn test_main() {
    x := &TestObj{
        a: 1
        b: 1
    }
    $for field in TestObj.fields {
        run_fn(fn [x, field] () {
            (*x).$(field.name) += 1
        })
    }
    assert x.a == 2
    assert x.b == 2
}

fn run_fn(f fn ()) {
    f()
}