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// run-pass
#![feature(try_trait)]
use std::ops::Try;
enum MyResult<T, U> {
Awesome(T),
Terrible(U)
}
impl<U, V> Try for MyResult<U, V> {
type Ok = U;
type Error = V;
fn from_ok(u: U) -> MyResult<U, V> {
MyResult::Awesome(u)
}
fn from_error(e: V) -> MyResult<U, V> {
MyResult::Terrible(e)
}
fn into_result(self) -> Result<U, V> {
match self {
MyResult::Awesome(u) => Ok(u),
MyResult::Terrible(e) => Err(e),
}
}
}
fn f(x: i32) -> Result<i32, String> {
if x == 0 {
Ok(42)
} else {
let y = g(x)?;
Ok(y)
}
}
fn g(x: i32) -> MyResult<i32, String> {
let _y = f(x - 1)?;
MyResult::Terrible("Hello".to_owned())
}
fn h() -> MyResult<i32, String> {
let a: Result<i32, &'static str> = Err("Hello");
let b = a?;
MyResult::Awesome(b)
}
fn i() -> MyResult<i32, String> {
let a: MyResult<i32, &'static str> = MyResult::Terrible("Hello");
let b = a?;
MyResult::Awesome(b)
}
fn main() {
assert!(f(0) == Ok(42));
assert!(f(10) == Err("Hello".to_owned()));
let _ = h();
let _ = i();
}
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