moo/
lib.rs

1use std::borrow::Cow;
2
3pub trait Moo {
4    fn moo(&self) -> ! {
5        panic!("Moooooooooo!")
6    }
7}
8
9impl<'a, T> Moo for Cow<'a, T>
10where
11    T: ToOwned + ?Sized
12{
13}
14
15#[cfg(test)]
16mod tests {
17    use super::*;
18
19    #[test]
20    #[should_panic(expected = "Moooooooooo!")]
21    fn it_moos() {
22        Cow::Borrowed("lol").moo()
23    }
24}