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//@ run-pass
// Test associated types appearing in struct-like enum variants.
use self::VarValue::*;
pub trait UnifyKey {
type Value;
fn to_index(&self) -> usize;
}
pub enum VarValue<K:UnifyKey> {
Redirect { to: K },
Root { value: K::Value, rank: usize },
}
fn get<'a,K:UnifyKey<Value=Option<V>>,V>(table: &'a Vec<VarValue<K>>, key: &K) -> &'a Option<V> {
match table[key.to_index()] {
VarValue::Redirect { to: ref k } => get(table, k),
VarValue::Root { value: ref v, rank: _ } => v,
}
}
impl UnifyKey for usize {
type Value = Option<char>;
fn to_index(&self) -> usize { *self }
}
fn main() {
let table = vec![/* 0 */ Redirect { to: 1 },
/* 1 */ Redirect { to: 3 },
/* 2 */ Root { value: Some('x'), rank: 0 },
/* 3 */ Redirect { to: 2 }];
assert_eq!(get(&table, &0), &Some('x'));
}
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