1 trait A: B + A {} 2 //~^ ERROR cycle detected when computing the super predicates of `A` [E0391] 3 4 trait B {} 5 6 impl A for () {} 7 8 impl B for () {} 9 main()10 fn main() { 11 let a: Box<dyn A> = Box::new(()); 12 let _b: Box<dyn B> = a; 13 } 14