rust/tests/ui/specialization/specialization-default-item...

36 lines
831 B
Rust

//@ revisions: classic coherence next
//@[next] compile-flags: -Znext-solver
//@[coherence] compile-flags: -Znext-solver=coherence
//@[classic] check-pass
//@[classic] known-bug: #105782
// Should fail. Default items completely drop candidates instead of ambiguity,
// which is unsound during coherence, since coherence requires completeness.
#![feature(specialization)]
#![allow(incomplete_features)]
trait Default {
type Id;
}
impl<T> Default for T {
default type Id = T;
}
trait Overlap {
type Assoc;
}
impl Overlap for u32 {
type Assoc = usize;
}
impl Overlap for <u32 as Default>::Id {
//[coherence]~^ ERROR conflicting implementations of trait `Overlap` for type `u32`
//[next]~^^ ERROR conflicting implementations of trait `Overlap` for type `u32`
type Assoc = Box<usize>;
}
fn main() {}