pub fn closure_param(a: i32, b: Box<dyn Fn(i32) -> i32>) → i32  :2-4
pub fn deep_generics(v: Vec<Box<dyn Fn(i32) -> i32>>) → usize  :5-7
pub fn nested_result(x: Result<Option<Vec<i32>>, String>) → usize  :8-10
