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use std::borrow::Borrow;
use std::cmp::Ordering;
use std::marker::PhantomData;
#[derive(PartialEq, Default)]
//~^ ERROR conflicting implementations of trait `PartialEq<Interval<_>>` for type `Interval<_>`
pub(crate) struct Interval<T>(PhantomData<T>);
// This impl overlaps with the `derive` unless we reject the nested
// `Interval<?1>: PartialOrd<Interval<?1>>` candidate which results
// in a -- currently inductive -- cycle.
impl<T, Q> PartialEq<Q> for Interval<T>
where
T: Borrow<Q>,
Q: ?Sized + PartialOrd,
{
fn eq(&self, _: &Q) -> bool {
true
}
}
impl<T, Q> PartialOrd<Q> for Interval<T>
where
T: Borrow<Q>,
Q: ?Sized + PartialOrd,
{
fn partial_cmp(&self, _: &Q) -> Option<Ordering> {
None
}
}
fn main() {}
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