37 lines
878 B
Rust
37 lines
878 B
Rust
// run-pass
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trait Speak : Sized {
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fn say(&self, s:&str) -> String;
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fn hi(&self) -> String { hello(self) }
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}
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fn hello<S:Speak>(s:&S) -> String{
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s.say("hello")
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}
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impl Speak for isize {
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fn say(&self, s:&str) -> String {
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format!("{}: {}", s, *self)
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}
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}
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impl<T: Speak> Speak for Option<T> {
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fn say(&self, s:&str) -> String {
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match *self {
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None => format!("{} - none", s),
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Some(ref x) => { format!("something!{}", x.say(s)) }
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}
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}
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}
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pub fn main() {
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assert_eq!(3.hi(), "hello: 3".to_string());
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assert_eq!(Some(Some(3)).hi(),
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"something!something!hello: 3".to_string());
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assert_eq!(None::<isize>.hi(), "hello - none".to_string());
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assert_eq!(Some(None::<isize>).hi(), "something!hello - none".to_string());
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assert_eq!(Some(3).hi(), "something!hello: 3".to_string());
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}
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