rust/tests/ui/coherence/coherence-overlap-unnormalizable-projection-0.rs

43 lines
902 B
Rust

// Regression test for soundness issue #114061:
// "Coherence incorrectly considers `unnormalizable_projection: Trait` to not hold even if it could"
#![crate_type = "lib"]
//@ revisions: classic next
//@[next] compile-flags: -Znext-solver
trait WhereBound {}
impl WhereBound for () {}
pub trait WithAssoc<'a> {
type Assoc;
}
// These two impls of `Trait` overlap:
pub trait Trait {}
impl<T> Trait for T
where
T: 'static,
for<'a> T: WithAssoc<'a>,
for<'a> <T as WithAssoc<'a>>::Assoc: WhereBound,
{
}
impl<T> Trait for Box<T> {} //~ ERROR conflicting implementations of trait `Trait` for type `Box<_>`
// A downstream crate could write:
//
// use upstream::*;
//
// struct Local;
// impl WithAssoc<'_> for Box<Local> {
// type Assoc = ();
// }
//
// fn impls_trait<T: Trait>() {}
//
// fn main() {
// impls_trait::<Box<Local>>();
// }