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23 lines
540 B
Rust
23 lines
540 B
Rust
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// check-pass
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// Allow this for now, can remove this UI test when this becomes a hard error.
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#![allow(implied_bounds_entailment)]
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use std::collections::hash_map::{Keys, HashMap};
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use std::marker::PhantomData;
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trait MapAssertion<'a, K, V, R> {
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fn key_set(&self) -> Subject<Keys<K, V>, (), R>;
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}
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struct Subject<'a, T, V, R>(PhantomData<(&'a T, V, R)>);
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impl<'a, K, V, R> MapAssertion<'a, K, V, R> for Subject<'a, HashMap<K, V>, (), R>
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{
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fn key_set(&self) -> Subject<'a, Keys<K, V>, (), R> {
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todo!()
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}
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}
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fn main() {}
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