mirror of https://github.com/rust-lang/rust
50 lines
1.1 KiB
Rust
50 lines
1.1 KiB
Rust
enum DropOption<T> {
|
|
Some(T),
|
|
None,
|
|
}
|
|
|
|
impl<T> Drop for DropOption<T> {
|
|
fn drop(&mut self) {}
|
|
}
|
|
|
|
// Dropping opt could access the value behind the reference,
|
|
fn drop_enum(opt: DropOption<&mut i32>) -> Option<&mut i32> {
|
|
match opt {
|
|
DropOption::Some(&mut ref mut r) => { //~ ERROR
|
|
Some(r)
|
|
},
|
|
DropOption::None => None,
|
|
}
|
|
}
|
|
|
|
fn optional_drop_enum(opt: Option<DropOption<&mut i32>>) -> Option<&mut i32> {
|
|
match opt {
|
|
Some(DropOption::Some(&mut ref mut r)) => { //~ ERROR
|
|
Some(r)
|
|
},
|
|
Some(DropOption::None) | None => None,
|
|
}
|
|
}
|
|
|
|
// Ok, dropping opt doesn't access the reference
|
|
fn optional_tuple(opt: Option<(&mut i32, String)>) -> Option<&mut i32> {
|
|
match opt {
|
|
Some((&mut ref mut r, _)) => {
|
|
Some(r)
|
|
},
|
|
None => None,
|
|
}
|
|
}
|
|
|
|
// Ok, dropping res doesn't access the Ok case.
|
|
fn different_variants(res: Result<&mut i32, String>) -> Option<&mut i32> {
|
|
match res {
|
|
Ok(&mut ref mut r) => {
|
|
Some(r)
|
|
},
|
|
Err(_) => None,
|
|
}
|
|
}
|
|
|
|
fn main() {}
|