fn make_closure<'a, T>() -> Box<dyn Fn(&'a i32)>
where
    T: std::fmt::Debug + CreateFromI32Ref<'a>
{
    Box::new(move |i32_ref: &i32| {
        T::create_from_i32_ref(i32_ref).process()
    })
}

trait CreateFromI32Ref<'a>: Sized {
    fn create_from_i32_ref(i32_ref: &'a i32) -> Self;
    fn process(self) {
        println!("processing...")
    }
}

impl<'a> CreateFromI32Ref<'a> for i32 {
    fn create_from_i32_ref(i32_ref: &'a i32) -> i32 {
        *i32_ref
    }
}

impl<'a> CreateFromI32Ref<'a> for &'a i32 {
    fn create_from_i32_ref(i32_ref: &'a i32) -> &'a i32 {
        i32_ref
    }
}

fn main() {
    make_closure::<i32>()(&100i32);
    make_closure::<&i32>()(&100i32);
}