1 trait X<'a> 2 where 3 for<'b> <Self as X<'b>>::U: Clone, 4 { 5 type U: ?Sized; 6 } f<'a, T: X<'a> + ?Sized>(x: &<T as X<'a>>::U)7fn f<'a, T: X<'a> + ?Sized>(x: &<T as X<'a>>::U) { 8 //~^ ERROR the trait bound `for<'b> <T as X<'b>>::U: Clone` is not satisfied 9 <<T as X<'_>>::U>::clone(x); 10 } 11 main()12pub fn main() { 13 f::<dyn X<'_, U = str>>("abc"); 14 } 15