blob: 3bae0f1730994d50d4d69450ab309422938165eb (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
#![feature(type_alias_impl_trait)]
trait Static: 'static {}
impl Static for () {}
type Gal<T> = impl Static;
fn _defining<T>() -> Gal<T> {}
trait Callable<Arg> { type Output; }
/// We can infer `<C as Callable<Arg>>::Output: 'static`,
/// because we know `C: 'static` and `Arg: 'static`,
fn box_str<C, Arg>(s: C::Output) -> Box<dyn AsRef<str> + 'static>
where
Arg: Static,
C: ?Sized + Callable<Arg> + 'static,
C::Output: AsRef<str>,
{
Box::new(s)
}
fn extend_lifetime(s: &str) -> Box<dyn AsRef<str> + 'static> {
type MalformedTy = dyn for<'a> Callable<Gal<&'a ()>, Output = &'a str>;
//~^ ERROR binding for associated type `Output` references lifetime `'a`
box_str::<MalformedTy, _>(s)
}
fn main() {
let extended = extend_lifetime(&String::from("hello"));
println!("{}", extended.as_ref().as_ref());
}
|
