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//@ run-pass
// Elaborated version of the opening example from RFC 738. This failed
// to compile before variance because invariance of `Option` prevented
// us from approximating the lifetimes of `field1` and `field2` to a
// common intersection.
#![allow(dead_code)]
struct List<'l> {
field1: &'l i32,
field2: Option<&'l i32>,
}
fn foo(field1: &i32, field2: Option<&i32>) -> i32 {
let list = List { field1: field1, field2: field2 };
*list.field1 + list.field2.cloned().unwrap_or(0)
}
fn main() {
let x = 22;
let y = Some(3);
let z = None;
assert_eq!(foo(&x, y.as_ref()), 25);
assert_eq!(foo(&x, z.as_ref()), 22);
}
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