tests/ui/question_mark.rs

   1 fn some_func(a: Option<u32>) -> Option<u32> {
   2         if a.is_none() {
   3                 return None
   4         }
   5
   6         a
   7 }
   8
   9 pub enum SeemsOption<T> {
  10     Some(T),
  11     None
  12 }
  13
  14 impl<T> SeemsOption<T> {
  15     pub fn is_none(&self) -> bool {
  16         match *self {
  17             SeemsOption::None => true,
  18             SeemsOption::Some(_) => false,
  19         }
  20     }
  21 }
  22
  23 fn returns_something_similar_to_option(a: SeemsOption<u32>) -> SeemsOption<u32> {
  24     if a.is_none() {
  25         return SeemsOption::None;
  26     }
  27
  28     a
  29 }
  30
  31 pub struct SomeStruct {
  32         pub opt: Option<u32>,
  33 }
  34
  35 impl SomeStruct {
  36         pub fn func(&self) -> Option<u32> {
  37                 if (self.opt).is_none() {
  38                         return None;
  39                 }
  40
  41                 self.opt
  42         }
  43 }
  44
  45 fn main() {
  46         some_func(Some(42));
  47         some_func(None);
  48
  49         let some_struct = SomeStruct { opt: Some(54) };
  50         some_struct.func();
  51
  52     let so = SeemsOption::Some(45);
  53     returns_something_similar_to_option(so);
  54 }