blob: 222c754394569d2541cd008d10b8c1d7c86e9095 (
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
32
33
34
35
36
37
38
39
|
// run-pass
// Check that a trait is still object-safe (and usable) if it has
// methods that return `Self` so long as they require `Self : Sized`.
trait Counter {
fn new() -> Self where Self : Sized;
fn tick(&mut self) -> u32;
}
struct CCounter {
c: u32
}
impl Counter for CCounter {
fn new() -> CCounter { CCounter { c: 0 } }
fn tick(&mut self) -> u32 { self.c += 1; self.c }
}
fn preticked<C:Counter>() -> C {
let mut c: C = Counter::new();
tick(&mut c);
c
}
fn tick(c: &mut dyn Counter) {
tick_generic(c);
}
fn tick_generic<C:?Sized+Counter>(c: &mut C) {
c.tick();
c.tick();
}
fn main() {
let mut c = preticked::<CCounter>();
tick(&mut c);
assert_eq!(c.tick(), 5);
}
|
