rust/tests/ui/question_mark.rs

55 lines
854 B
Rust
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2018-01-28 01:04:22 +01:00
fn some_func(a: Option<u32>) -> Option<u32> {
if a.is_none() {
return None
}
a
}
pub enum SeemsOption<T> {
Some(T),
None
}
impl<T> SeemsOption<T> {
pub fn is_none(&self) -> bool {
match *self {
SeemsOption::None => true,
SeemsOption::Some(_) => false,
}
}
}
fn returns_something_similar_to_option(a: SeemsOption<u32>) -> SeemsOption<u32> {
if a.is_none() {
return SeemsOption::None;
}
a
}
pub struct SomeStruct {
pub opt: Option<u32>,
}
impl SomeStruct {
pub fn func(&self) -> Option<u32> {
if (self.opt).is_none() {
return None;
}
self.opt
}
}
fn main() {
some_func(Some(42));
some_func(None);
let some_struct = SomeStruct { opt: Some(54) };
some_struct.func();
let so = SeemsOption::Some(45);
returns_something_similar_to_option(so);
}