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