22     struct Opt {  in required_argument()  struct
23         arg: i32,  in required_argument()
36     struct Opt {  in argument_with_default()  struct
38         arg: i32,  in argument_with_default()
51     struct Opt {  in auto_value_name()  struct
52         my_special_arg: i32,  in auto_value_name()
68     struct Opt {  in explicit_value_name()  struct
70         my_special_arg: i32,  in explicit_value_name()
87     struct Opt {  in option_type_is_optional()  struct
88         arg: Option<i32>,  in option_type_is_optional()
101     struct Opt {  in vec_type_is_multiple_values()  struct
102         arg: Vec<i32>,  in vec_type_is_multiple_values()