src/test/ui/generic-associated-types/trait-objects.stderr

   1 error[E0038]: the trait `StreamingIterator` cannot be made into an object
   2   --> $DIR/trait-objects.rs:10:21
   3    |
   4 LL | fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize {
   5    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `StreamingIterator` cannot be made into an object
   6    |
   7    = help: consider moving `Item` to another trait
   8 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   9   --> $DIR/trait-objects.rs:4:10
  10    |
  11 LL | trait StreamingIterator {
  12    |       ----------------- this trait cannot be made into an object...
  13 LL |     type Item<'a> where Self: 'a;
  14    |          ^^^^ ...because it contains the generic associated type `Item`
  15
  16 error: aborting due to previous error
  17
  18 For more information about this error, try `rustc --explain E0038`.