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// check-pass
// compile-flags: -Znext-solver
#![feature(rustc_attrs, marker_trait_attr)]
#[rustc_coinductive]
trait Trait {}
impl<T, U> Trait for (T, U)
where
(U, T): Trait,
(T, U): Inductive,
(): ConstrainToU32<T>,
{}
trait ConstrainToU32<T> {}
impl ConstrainToU32<u32> for () {}
// We only prefer the candidate without an inductive cycle
// once the inductive cycle has the same constraints as the
// other goal.
#[marker]
trait Inductive {}
impl<T, U> Inductive for (T, U)
where
(T, U): Trait,
{}
impl Inductive for (u32, u32) {}
fn impls_trait<T, U>()
where
(T, U): Trait,
{}
fn main() {
impls_trait::<_, _>();
}
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