rust/tests/ui/specialization/specialization-default-items-drop-coherence.rs

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// check-pass
// 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 {
type Assoc = Box<usize>;
}
fn main() {}